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(Fahrenheit) 451 ppm

Posted on 11 December 2011 by Bob Lacatena

A Chilling Thought

The recent Schmittner paper on equilibrium climate sensitivity, estimated by using a simple climate model and a comparison with the Last Glacial Maximum, led me to a new and thought-provoking perspective on exactly what man is doing.  One can use an even simpler model — a simple rule of thumb — to frame exactly what is happening and what we might expect.  One need not even go as far as a simple computer climate model to arrive at an unsettling conclusion. 

Scientists have attempted to define a minimum safe global mean temperature increase, above which we are really taking our chances and rolling the dice.  To stay within this they have computed a threshold of CO2 levels beyond which we should not go.  Based on a best estimate of climate sensitivity of 3˚C per doubling of CO2 and a target temperature increase of 2˚C, the CO2 target level is 450 ppm.

But 451 ppm is just as important a number.

Of Knobs and Levers

CO2 is termed the Earth's biggest control knob.  It hadn't been until now, because a knob implies something that someone can turn to control things.  In a normal, natural world and on relatively short timescales, say tens of thousands of years, carbon dioxide is interlocked with global mean temperature and other variables.  Temperatures can drive carbon dioxide levels up or down, which in turn drive temperatures further up or down.

Carbon dioxide acts as a feedback that enhances temperature changes.

Figure 1: Vostok ice core records for carbon dioxide concentration and temperature change.

Figure 1: Vostok ice core records for carbon dioxide concentration and temperature change.

This is most obvious during the transitions between glacial and interglacial periods, when temperatures rise or drop and CO2 seems to follow along like a happy puppy.  What is not obvious when looking at the readings is that while orbital forcings cause the initial change in temperatures, and CO2 levels rise or fall in accordance with that initial change, the subsequent temperatures themselves also rise and fall in accordance with the changing CO2 levels.

The basic formula behind a glacial termination is that something (orbital forcings) starts the increase in temperature.  Actually, what really starts it is a change in the length and severity of northern hemisphere summers, without changing the overall amount of radiation reaching the planet at all.  That stays fairly constant.  

These seasonal changes in turn cause the ice sheets covering the northern hemisphere land masses to begin to melt.  This reflects less sunlight back into space, and that really does change the amount of energy that the planet receives from the sun, which leads to warming.  It also results in the release of methane, another powerful greenhouse gas, which warms the planet even further.

Then CO2 kicks in.  The oceans warm.  Warmer water cannot hold as much dissolved carbon dioxide and so the oceans release some CO2 into the atmosphere.  CO2 in the atmosphere causes warming.  The increased warming causes the ice sheets to retreat further, and the oceans to warm further, and more CO2 to be released.

This continues, but with limits.  There is (or had been) only so much CO2 that could make its way into the atmosphere.  The system only pushes this cycle so far.   The many previous glacial terminations in the past 2.5 million years (a period known as the Pleistocene Epoch) have seen lows of about 180 ppm of CO2, and highs between 250 ppm and 300 ppm.

The main point is that temperatures and CO2 are interlocked, or at least had been until now.  Temperature changes had to get the ball rolling, so on a graph they will lead the way, but the two work in concert.  One is not pulling a leash to drag the other along.  They each push and pull the other, working their way from low to high, or high to low, as an integrated system.

CO2 does not "lag" temperature.  That's a simplistic, inaccurate and indiscriminate view of a complex interaction.

Turning the Knob

Unfortunately, contrary to recent natural history, man has learned how to remove the regulator and to dial up a far higher level of CO2 in the atmosphere.  CO2 has become the climate's biggest control knob in the last two centuries or so, in the sense that it is in fact a control that mankind can twist, turn, tweak and, sadly, overdo.

A glacial termination happens on very, very long timescales relative to man.  What we have done in the past two centuries, however, applies a change to CO2 levels — implying an equivalent change in climate — that would otherwise take nature 10 to 12 thousand years.

CO2 was once interlocked with temperature.  In the past 200 years we have instead taken 337 gigatonnes of carbon out of the ground and injected it into the atmosphere and the oceans.  Nature spent the better part of several hundred million years converting that carbon into new forms (coal, oil, gas) and sequestering it deep under the surface of the earth.

Figure 2: Human CO2 emissions (blue, left y-axis, Source: IEA) vs. atmospheric CO2 concentration (red, right y-axis, Source: Mauna Loa record)

Figure 2: Human CO2 emissions (blue, left y-axis, Source: IEA) vs. atmospheric CO2 concentration (red, right y-axis, Source: Mauna Loa record)

Man will be able to undo in 200 years what took nature hundreds of millions of years to accomplish, and in so doing, in that same time frame, we are duplicating a feat that normally takes nature 10,000 years to accomplish (i.e. increasing atmospheric CO2 levels by two thirds).

And, as an important point, we have no idea if we are capable of duplicating nature's feat of again sequestering that carbon underground.  We have far too easily turned the knob in one direction, but with no capacity whatsoever to turn it in the other.

An Ice Age

For the past two and a half a million years this planet has been locked in an Ice Age, the Pleistocene Epoch, during which the poles are always covered with ice caps.  During glacial periods those ice caps extend much further down in the northern hemisphere, covering much of the land and oceans above the 34th parallel.  During interglacial periods, such as the one we are in now, the globe warms, the ice retreats and life gleefully expands to fill the space that opens up.

The common man on the street, however, uses the term "ice age" to refer to that glacial period where the permanent (year round) ice sheets extend as far as Michigan, Ohio, and Germany.

The transition out of such an "ice age" to our current world involves an appropriate temperature increase and an interlocked change in carbon dioxide from 180 ppm to 285 ppm.  It took an increase of 105 ppm, or a factor of 1.6, to get us from an "ice age" into the world in which we currently not only live, but thrive.

We have now, as a matter of the natural development of our own civilization and technology, unlocked vast stores of carbon that have been unavailable to the system throughout the Pleistocene Epoch.

By releasing that carbon — by burning fossil fuels and converting the long carbon chains into carbon dioxide — we have dramatically altered the system.  For 2.5 million years it has been seemingly impossible to naturally raise CO2 levels above 285 ppm.  It hasn't happened in dozens of glacial terminations.

We are now at 390 ppm and rising at an average of 2 ppm per year.

Imagine if we were to apply the same change to our world as was required to shift the planet from a glacial to an interglacial period (or in incorrect but layman's terms, from an "ice age" to our current climate). What if we were to raise CO2 levels from 285 ppm by an equivalent factor of 1.6?

That would mean raising CO2 levels to 451 ppm.

We're at 390 ppm now.  Moving from 390 ppm to 451 ppm is a change of a mere 61 ppm.  At the current rate of 2 ppm per year, with no further growth in emissions, that means we will reach 451 ppm in just 31 years.  By 2042 — by the time a 2 year old today turns 33 — we will have released forces equivalent to the transition from glacial period to an interglacial, from an "ice age" to our current "green age."

A Fire Age

What, then, will this new age, the one that follows our "green age," look like?  Various efforts at modeling and climate science attempt to develop a clear picture of the ecosystem, climatic and weather changes that will result, but while it may be important to anticipate the details, the final answer in a more general sense must at the minimum be very different from the world in which we live now.

If, in common parlance, a glacial period is termed an "ice age," while the world we live in today might be termed a "green age," then I would suggest that we are now heading into a "fire age."

Deserts are expected to expand with the growth of the Hadley Cells.  Droughts and wild fires are expected to increase.  Crops will be less productive.  Sea levels will rise as more and more ice melts.

During the Eemian, an interglacial period that began roughly 130,000 years ago and lasted 16,000 years, temperatures in Europe north of the Alps were roughly 1-2˚C higher than today.  Sea levels were 4 to 6 meters higher.  CO2 levels were roughly at 300 ppm.

Going further back, during a warm period 3 million years ago within the Pliocene epoch, temperatures were a mere 2-3˚C warmer than today (see here and here and here).  Sea levels were 25 meters higher.  CO2 levels were between 360 ppm and 400 ppm.

How much will the world change if we increase CO2 levels to 451 ppm?  Time will tell, but one way or the other we may be duplicating in strength in just 200 years what nature itself requires 10,000 years to do.  We are applying that forcing beyond the point at which nature has always stopped.

We are duplicating within that short time period the greatest single force on this planet that nature alone has wielded for the past 2.5 million years.  But nature does so slowly, carefully and predictably.

We are doing so rapidly, erratically, and without awareness or understanding of the consequences, or even taking long enough to recognize that what we are doing does indeed have an irreversible effect.

A Fire Extinguisher

There are some important points to make to temper this realization.

The first is to recognize that in a glacial termination there are forces at work that are not present in today's world.  The retreat of the vast ice sheets account by some estimates for 54% of the global temperature change during glacial termination.  These changes in ice sheets also have huge effects on ocean currents which in turn affect climate.

In today's world, with ice only covering much smaller areas at the poles, that particular influence on climate change is greatly reduced.  As such we should not expect the same response in temperature, and hopefully in overall climate change, with the same relative increase in CO2.

Best Estimates of Climate Sensitivity

Figure 3: Various estimates of climate sensitivity (Knutti and Hegerl 2008).

 On the other hand, this is a new paradigm and one without equal in natural history.  During a glacial termination, the spread of vegetation actually helps to hold CO2 levels down by drawing it out of the atmosphere and using it for plant growth as the forests of the world reclaim the land once covered by glaciers and ice.  In our world, if things get too bad, huge swaths of vegatation may die, for instance if the Amazon rain forests turn in whole or in part into savanna or if the deserts of the world expand due to changes in precipitation patterns and the growth of the Hadley Cells.  This will have the opposite effect, adding even more CO2 to the atmosphere rather than drawing it down.

It's difficult to predict where things will go.  That's what science and climate models and paleo studies are all trying to determine.  There is some reason to hope that the overall temperature and climate change will not be dramatic, but there's also good reason to believe that the effects will be more than strong enough to adversely affect billions of lives.

Ice Age Fauna of Northern Spain

Figure 4: Now extinct fauna from the last glacial period in Northern Spain (image courtesty Wikipedia Commons).

Decades, Centuries or Millenia

Another major difference is that in the case of a glacial termination the changes in both temperatures and CO2 levels are very, very slow, taking more than 10,000 years, and changing continuously in concert.

In our situation we have ratcheted up the CO2 levels in a blink of an eye from nature's perspective.  In 1800 CO2 levels were approximately at 285 ppm.  By 1900 they were closer to 290 ppm.  As of 2010 they were at 390 ppm and rising fast.

So how fast will temperatures rise? This is another area of study and debate in climate science.  There is a lot of variability in the system.  There is a vast amount of water in the oceans capable of absorbing a lot of energy before the planet reaches a new equilibrium temperature.  The ultimate, final equilibrium temperature also depends on feedbacks, and those kick in at different rates.  How quickly will the Amazon transition to savanna, if at all?  How quickly will deserts expand?  How much natural CO2 will be released and add to anthropogenic sources?  How great and how important will the melting of Artic ice become?  How much methane will be released, and how quickly, from the permafrost regions of the Arctic?

We will reach 451 ppm at the current rate by 2042, but that doesn't mean we'll change the planet that quickly. By 2042 we will have "set the thermostat" to the new setting, but it could take anywhere from decades to hundreds to thousands of years for the planet to reach its final, new equilibrium temperature.  No one alive today will live to see what we have utlimately done to planet.

The one thing we do know is that we are turning the thermostat up with no ability to turn it back down.  We are commiting the planet to a 451 ppm scenario with no firm idea of what that is going to mean and absolutely with no ability to draw CO2 levels back down to their natural 285 ppm levels.


It is a pure but poignant coincidence that the number discussed here — 451 ppm — is so close to another number that has been bandied about in recent days — 450 ppm.

450 ppm is — given a proposed, best estimate of climate sensitivity of 3˚C — the target level of CO2 that we must not pass if we want to maintain a reasonable chance of restraining climate change to a mere 2˚C increase.  2˚C has been chosen as a maximum "safe" upper bound to avoid truly dangerous climate change.  Any increase beyond that is deemed to be, by mere rule of thumb, unacceptable.

The math is simple, based on the logarithmic relationship between CO2 levels, climate sensitivity and temperature increase:

Ttarget = Tsensitivity • log2 ( CO2-target )

In English, this means that given a starting level CO2-initial of 285 ppm, a climate sensitivity (Tsensitivity) of 3˚C, and a temperature increase (Ttarget) of 2˚C, we arrive at a CO2-target of 450 ppm.

2 = 3 • log2 ( 450 )

Sadly, we may well find that even 2˚C itself is quite far from acceptable.

451 ppm is, as explained here, the forcing that implies a change from our current climate, a "green age," to a new and foreign world, just as it accompanied a change from an "ice age" (i.e. a glacial period) to our current climate.  That forcing caused a change in global mean temperatures of 3˚C to 5˚C, and completely recast the surface of the planet from one of sheets of ice to flourishing green.

One does not need a fantastic education in science or climate science to make a fairly basic, rule of thumb observation of where we may be headed.

One has to look at the similarity in these two numbers, 450 and 451, and wonder if nature isn't, in some small, intelligent-design kind of way, trying to tell us something.

CO2 Targets

Figure 5: Target CO2 levels.

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Comments 51 to 100 out of 106:

  1. #34 muoncounter : ‘Imagine the cost when those 'capacities' need to be developed and brought online at short notice because we sat around, pacified by those who claim 'its not bad,' and did nothing.’ The problem is not to say ‘it is not bad’ – just to observe that the ‘it could be worse than all you imagine’ strategy is pragmatically unfruitful for the last 10 years, beside the fact this strategy is usually biased with a selective presentation of what models actually produce in their projections or IPCC reports actually acknowledge in their conclusions. If somebody tells me ‘we’re nearly sure Amazon will become a savanna before the end of the century’ while science tells me ‘we don’t really know how Amazon will evolve during this century’, I’ve no reason to trust the first statement from an evidence-based perspective. And the same is true if you select just one or two publications among the whole literature. If SkS wants to be trusted, it’s necessary to rely strictly on what science says, including the mention of divergence among scientists teams and uncertainties in models, and to avoid ‘simplistic, inaccurate and indiscriminate view’ on climate change, to paraphrase Sphaerica. Skepticism about 'doom and gloom' discourse does not translate in approbation of optimistic statements (unfounded) and 'nothing-to-do' conclusion (undesirable). We fail to act seriously for now and we need to diagnose this failure, a misdiagnosis will just protract our collective failure. (Thanks for explanations about Climate Wizards). #35 Tom : ‘no national representative at Durban may deny the 2 degree C, 450 ppmv target, yet they have all just signed of on a deal that almost guarantees that we will exceed that target’ Yes but again, the good question is : why? I suggest here that the interpretation ‘climate negotiators do not fully think about the whole range of climate risks’ is wrong. They know the existence of low probability / high consequence events as we all know that. My hypothesis is that such events are not limited to climate change, but also of concern for economy and energy changes. #43 phila : ‘Foresight and planning, for instance. Unfortunately, these capacities tend to require accurate risk assessment, which is lacking on the "skeptical" side of the argument.’ That’s probably true if by ‘skeptic’ you mean ‘denier’. If not, it is false. An ‘accurate risk assessment’ is precisely what IPCC is committed to produce, so you must refer to IPCC reports. You produce a bad assessment if you prefer to rely selectively on a part of the literature or a particular hypothesis. That’s true for all domains, not just climate. You do not decide a health policy by focusing on the worst but unlikely hypothesis for a powerful emerging virus, because if you choose to do so, you forbid transport and trade so as to minimize human contacts, but you produce more harm than you avoid if your first hypothesis is wrong (or not the most probable when you have to decide in uncertain conditions). Further, a credible risk assessment includes the costs, benefits and uncertainties of the two terms of a choice. Everybody remember the large debates among specialists after the Stern report was published in 2006. Unfortunately, WG2 and WG3 are far less precise than WG1 when it comes to the evolution of human society under different boundary conditions for energy use. After all, human society is a complex system too and if we are rationally coherent, we should also fear the effects of brutal changes, poorly known ‘tipping points’, ‘black swans’, etc. The ‘grandeur nature’ experience of human history is a call for caution, isn’t it? For 20 years I read on climate and energy subjects, I’m really tired of the naive and over-optimistic ‘win-win’ discourses. If we want a climate decision, we need to first tell the truth to population about the difficulty of the task. For example, nearly all commentaries on Durban explain how sad it is not to extend immediately the Kyoto Protocol. But few recall that Kyoto Protocol did not achieve its very modest targets when grey energy from imports are considered. Do we really want to extend uncritically such a failure? It is totally irrational for me to proceed with such double discourses, wishful thinking and ignorance of reality. The most ambitious target (2 K / 450 ppm) decided at Copenhague and Cancun is supposed to be a 'victory'. But if it translates in a persistent blocking of climate diplomacy, that's just a defeat. The basic reality I observe is that we gave up more modest targets, like a progressive carbon tax on fossile producers or an immediate Green Fund for the third world, and wait for the 'ideal' solution that could never come, because many countries never ratified the Kyoto Protocol after 1997 and many still risk to act samely for the 2015 post-Kyoto Protocol. Again, the best is the enemy of the good and I tend to think the more radical postures are just the expression of impotence. (Sorry, most of my considerations are now OT here and I should have written them under the recent post about 2010 Carbon emissions. That's because the Sphaerica article coincided with the Durban conclusion, and it illustrates a type of perspective I can't agree with. Each element of this perspective is correct, with some conditional precisions, but IMO the agregate result is not convincing except for those who are already and intimely convinced that the worst issue is the most probable and that climate should the first concern in human affairs.)
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  2. angliss@12 "...that the cross correlations are so broad means that, as a function of lead and lag in a control system..." First, let me be perfectly clear that I am not interested in engaging in any arguments here. My response is intended only to clarify (and in one case amplify) what I meant, nothing more. I use the structure "x leads (or lags) y" only in terms of statistics of time series and never (or almost never) in direct relation to a dynamic system (or control system, as you call it). The time series data may result from observations of nature or may result from running a simulation model of a dynamic system. Within a dynamic system, I might speak of "delayed responses" and "time-lagged feedbacks" or "delayed feedbacks." I consider "simplistic" to be an inherent characteristic of a statistic. Simulation models of real dynamic systems are also "simplistic," some more so and some less so. I have had some small experience with simulation models of varying degrees of simplicity in various fields (demography, economics, politics, hydrology, urban and regional planning, etc.). I expand on my comment about discrimination being related to purpose, although it is off topic. I took a useful lesson from Anatol Rapoport about 1970. If we are interested in the biomass of small (not tiny, not large) mammals in our forest and want to know how it varies in time, then we trap some four-footed furries (FFFs), weigh them to determine their average mass, and conduct some surveys to estimate the total population of FFFs in our forest. We do this year after year and find that the FFF biomass seems to be at a stationary equilibrium. On the other hand, if we become interested in the life cycles of individual FFFs, then we may find it useful to discriminate between long-eared, short-tailed FFFs and short-eared, long-tailed FFFs. We may then find not a stationary equilibrium but a dynamic equilibrium (with an orbit in the phase space) and may even be led to discover a predator-prey relation between foxes and rabbits. The point is that how much (and what) we aggregate and how much (and what) we discriminate should bear a useful relation to our purpose in studying something and frequently has a direct impact on what we can discover. A small thought experiment: Suppose we have developed a perfect paleoclimate simulation model that with the proper initial data exactly reproduces all the available relevant time series data for the time period 799000 BC to 1000 AD. Will this model be able to correctly predict our future climate? I tend to doubt it. If we had such a model, then I think we would know more than we do now about some of the complex interactions we should take into acouunt. Nevertheless, we may be in an entirely new ball game with a new set of rules. Using the analogy with a business firm, we have taken a huge amount of long-term fixed assets (buried hydrocarbons, for example) and converted a small portion of them into current assets (plastics and crops, for example) and the vast majority into liquid assets in circulation (CO2 in the air and water). That may take us outside the applicability domain of our perfect paleoclimate model. Moreover, we appear to have started a long-term rapid warming episode with CO2 as the initiating GHG and with no large ice sheets in the NH. This also may take us outside the applicability domain of our perfect paleoclimate model. I frankly expect the next few thousand years to be very interesting with many new things to be learned about the climatology of Earth. We might even be able to observe what happens in a chaotic region of the system phase space.
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  3. "The problem is not to say ‘it is not bad’" Look at the 'Most Used Climate Myths' in the upper left of every SkS page. 'It's not bad' is #3. "the ‘it could be worse than all you imagine’ strategy is pragmatically unfruitful for the last 10 years" And thus you would counsel abandonment of this strategy? "what models actually produce in their projections or IPCC reports actually acknowledge in their conclusions." AR4 is from 2007. Research and data continue to accumulate. Contexts which were 'projections' then are coming into focus (see Arctic ice melt faster than expected, for example). "If somebody tells me ‘we’re nearly sure Amazon will become a savanna before the end of the century’" Such focus on a specific prediction about a specific area and a specific time frame tends to make one blind to the larger issues. There are still those in the denial-world who focus on 'the Himalayas will be free of snow by 20xx' as a 'failure,' entirely missing the point that worldwide glaciers and snowpacks are dwindling before our eyes. This is not about predicting specific events; 'the trend's the thing.' "If SkS wants to be trusted, it’s necessary to rely strictly on what science says," Please provide an example where that is not the case; in this, the 'fire age' discussion is very clearly an extrapolation: What, then, will this new age, the one that follows our "green age," look like? ... I would suggest that we are now heading into a "fire age.". "Skepticism about 'doom and gloom' discourse..." Turn this premise around: Failure to discuss an increase in the frequency/intensity of extreme events would be gross negligence indeed.
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  4. BillEverett@50: Methane is a potent greenhouse gas (20-30x CO2) because its concentration is so low. It's on the steep initial (non-logarithmic) part of the absorption vs concentration curve. On the other hand, the obvious oxidation channel, CH4 + 2O2 -> CO2 + 2H2O, makes three greenhouse-gas molecules out of 1. This is oxidation by combustion, of course, but even if there are other reaction channels, you're still going to manufacture more GHG than you started with. So the stuff is quite potent.
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    If somebody tells me ‘we’re nearly sure Amazon will become a savanna before the end of the century’ while science tells me ‘we don’t really know how Amazon will evolve during this century’...
    With this comment you've demonstrated that you clearly missed the underlying point of my post, and so cannot seem to comprehend its value (at least, as I perceive it). My point is that the details (such as if and when the Amazon will transition) are very important on one level, but completely irrelevant on another. If you need details like that you are never going to be convinced, because that is your nature. [As an aside, if a doctor told you that you had terminal cancer but couldn't tell you the exact time and date of your demise, would you than ignore his diagnosis?] But the point of this post is that we don't really have to work out that many of the details to see that what we're doing is very, very risky. We are applying a force of nature that has continually reshaped the world more than a dozen times in the past million years alone. We're playing with fire, plain and simple. Do I guarantee we'll get burnt? No. Can I guarantee that letting a child play with matches will hurt them? No. Do I let children play with matches? No.
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  6. #53 muoncounter : "And thus you would counsel abandonment of this strategy?" It will decline by itself. Nobody need fuzzy and scary pictures: deniers are totally immune, believers are already convinced, policymakers henceforth search precise projections in climate and creative solutions in energy. "AR4 is from 2007" "Failure to discuss an increase in the frequency/intensity of extreme events would be gross negligence indeed" SREX is from 2011: its conclusions are supposed to be the IPCC synthesis of recent scientific literature about extreme events and how to cope with them. Of course we must discuss that. By the way, does SkS wait for the full report? I was amazed to find no article when the SPM was released.
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  7. Sphaerica: Kudos on a very well written article. Having said that, perhaps you should add a paragraph or two about the impact that the ever increasing levels of CO2 released into the atmopshere by the activites of mankind is having, and will have, on the the pH of the world's ocean system.
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  8. Sphaerica : As an aside, if a doctor told you that you had terminal cancer but couldn't tell you the exact time and date of your demise, would you than ignore his diagnosis? This question shows that you miss my point, as I'm supposed to have missed yours! We would call here that a dialogue de sourds. The correct metaphor would be in my mind: if a doctor diagnose a cancer, I don't want him to give me a broad description of the disease and the agony, but a realist prediction of the symptom I'll suffer, a precise assessment of my chance of remission at diverse conditions, the treatments I can access, their costs, their side-effects, etc. And I think it is the usual way we deal with adverse condition. Of course we're "playing with matches". That could be a succinct and symbolic definition of Anthropocene, beginning with the agricultural Neolithic according to Ruddiman, with the industrial Watt's engine commercialization according to Crutzen. (Sooner for me, with the first megafauna extinction of Paleolithic—notably due to fire use, for staying on the metaphor). I take the Anthropocene hypothesis seriously. We affect the whole Earth system, and we know that, so time is to fix the rules of the game. That does not mean to forbid the game. And we won't discuss these rules from the nature's point of view, but from humans' point of view. That's why the consequences of our act on ecosystem services must be precisely adressed, so as to allow their acceptation or rejection.
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  9. En francais, "sourd" = "deaf". (Sorry about the circumflex). I do have the sense that you two are on the same wavelength, but not hearing what the other guy is saying. On a besoin d'un appareil auditif? This is a really good discussion. Keep it up, both of you.
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  10. " The problem is not to say ‘it is not bad’ – just to observe that the ‘it could be worse than all you imagine’ strategy is pragmatically unfruitful for the last 10 years .... Again, the best is the enemy of the good and I tend to think the more radical postures are just the expression of impotence. " Not quite. This is the expression of an unsuccessful communicator bewailing the failure of earlier communications. The correct communication strategy is unfortunately not well-suited to the sound-bite era. The right message is 'We can get ourselves out of trouble so long as we get started on it right away.' Unfortunately, apart from this message being a bit hard to get across, it's being shouted down by other messages. Think of getting a lazy teenager to clean up their room. Yes, you will get smells and mould, and moths, and cockroaches, and mice, maybe even rats into this house if you don't clean up your food waste and your dirty clothes. See! Your favourite sneakers are ruined by mould and moisture! And as you get more and more frustrated, the teenager in question doesn't even notice because of the headphones blaring and blocking any message you might want to get across.
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  11. Sphaerica, I also hope we do not see 450ppm in 2042. And I agree with your critique of my analysis of emissions surpassing 2ppm a year on average in years to come. I would be nice if they stayed at 2ppm, but that seems unlikely considering the amount of carbon being dumped in the atmosphere. I agree also that by the late 2020's our climate will have deteriorated so much with increasing violent events, droughts, fires and increasing human suffering- that these nations will be forced into doing something to reverse the hellish path we are on. I hope C02 will peak at 650ppm, and begin a slow decline- but even that figure is going to cause our society to change dramatically. The biggest question mark is at what level C02 does all that permafrost begin to release methane.
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  12. BillEverett #52:
    Suppose we have developed a perfect paleoclimate simulation model that with the proper initial data exactly reproduces all the available relevant time series data for the time period 799000 BC to 1000 AD. Will this model be able to correctly predict our future climate? I tend to doubt it. If we had such a model, then I think we would know more than we do now about some of the complex interactions we should take into acouunt. Nevertheless, we may be in an entirely new ball game with a new set of rules.
    Wrong, the Laws of Physics, which determine climate, were exactly the same 800,000 years ago as they are today. They have not changed. Increasing forcings by increasing CO2 will have the same effect on temperature as a similar forcing due to orbital variation. Temperature will go up and feed backs will come into play.
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  13. Ian Forrester@62: The reason for my skepticism about the ability of my hypothetical "perfect" paleoclimate model to predict our future correctly, in general, has to do with the simplicity of models. More specifically, I see no reason for my hypothetical paleoclimate model, for example, to include arctic permafrost as a source of CH4. "Applicability domain" of a model is a standard concept in theoretical physics. In our current situation, I see several reasons for thinking that we are or soon might be outside the applicability domain of the "perfect" paleoclimate model. This has nothing to do with the universal validity of fundamental physical laws. Without examining a climate model in detail, I can nevertheless say that many of the couplings in the model are phenomenological approximations, i.e., they are not equations derived from fundamental physical laws. It is very often the case that an increase in the order of a coupling approximation is necessary for increasing the applicability domain of a model.
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  14. BillEverett - "Without examining a climate model in detail, I can nevertheless say that many of the couplings in the model are phenomenological approximations, i.e., they are not equations derived from fundamental physical laws..." I believe the proper term here is "talking through your hat". I would suggest actual study of global circulation climate models before making such unsupported statements. The whole point of global climate modelling is to take physical laws, compute fine detailed effects (as fine as the computing time and memory allows), and see what happens. Your statement is quite simply unsupportable, reflecting a lack of knowledge (and a surfeit of opinion) on your part.
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  15. BillEverett - My previous post is/was strongly worded, perhaps too much so. But I would have to note that your "hypothetical paleoclimate model" with bears little resemblance to what you are criticizing. Hence your statements are really a strawman argument, a logical fallacy.
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  16. KR, Bill : I'm not sure that there's a real basis for your dissent. Of course climate models, even AOGCMs of AR4 and the future Earth System Models of AR5, are "approximations" because many phenomenons on small scale are semi-empirically parametrized. And many others are poorly known or unknown (eg all details of the biogeochemical cycles, for example future behavior of CH4 sources). Gavin Schmidt once precised this fact in an introduction to the physics of climate modeling (my emphasis): Current climate models yield stable and nonchaotic climates, which implies that questions regarding the sensitivity of climate to, say, an increase in greenhouse gases are well posed and can be justifiably asked of the models. Conceivably, though, as more components — complicated biological systems and fully dynamic ice-sheets, for example — are incorporated, the range of possible feedbacks will increase, and chaotic climates might ensue. So, the fact that climate is non-chaotic does not appear so much as a robust and intrinsic physical property of climate, but rather just as a provisional conclusion from the current physics of models. Jsquared : ah, on finira bien par s'entendre :D
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  17. Sphaerica : to continue with the playing matches / Anthropocene debate, and to understand our divergence, you seem to assume that climate stabilization would be good thing in itself. In the same spirit, Steve L @6 also suggested that you ‘over-anthropomorphized nature’. Maybe I’m wrong, but this the impression I have. It is clearly not the way I approach the question : climate change is not a good or bad thing in itself, the ultimate qualification of good/bad relies on human evaluation about the consequences of climate change on human society. I assume this is an anthropocentric point of view, and I think such an anthropocentrism is the rule for a majority of humans in their personal and collective choices. It does not mean nature has no value at all, to the contrary. A majority of humans can value biodiversity (for example) but this value is ultimately human-based. That is the sense of the Millenium Ecosystem Assessment , which analysed changes in ecosystem in the perspective of human (not animal or vegetal) well-being. So, I’m not satisfied at all with fuzzy predictions / estimations that warming may be 2 to 8 K, biodiversity loss 10% to 70%, crops productivity change +5% to -40%, ultimate cost-accessible fossil reserve from 600 to 6000 GtC, climate equilibrium sensitivity pace decades to millenias, 2100 sea level change 40cm to 160 cm, and so on. Because usually, the lower and the higher extremes of these ranges have not the same consequences for the human choices in term of evaluation of well-being. Usually, I’m answered something like : “OK but the only fact that there is a X% probability for the most adverse hypothesis should be the guide of our action”. But that could be true until you prove that the action in question has not itself a higher probability of adverse effect on human well-being. If your prior assumption is that action is risk-free, your value judgment is unbalanced. If you assume (as I do) that the fossil-based development during the last two centuries is one of the most astonishing accomplishment in human history, and a huge amelioration of human well-being for those who have benefited of it, the simple idea that we must cut very fastly the fossil (80%) basis of this long term trend is to be analysed very carefully. And particularly when the majority of humanity just begins to access the welfare Westerners already enjoy. Because a bad idea could easily produce a bad outcome, and human history is very clear on that point (for example near thirty million Chinese died of famine in 1959-1961 because of Mao’s delirium about agriculture, Hitler’s ascent because Germany was stupidly humiliated after 1918 and because of 1929 crisis, etc. Unintended consequences are unhappily a constant of human fate, and that’s not just true about externalities of fossil use!) Of course, the secular progress I refer to is due to energy, not fossil in itself. And to many other factors like democracy, education, trade, etc. But fundamentally, I believe economy and society depends on their energy basis, if you have just biomass and human-animal muscles as sources of energy, you’ll just produce something like a feudal society, with no means to transform nature and society, to create wealth and all the interesting things we can do with wealth (for example sophisticated study of climate). That’s why I say that climate challenge depends now mostly on energy challenge : you have to produce a mostly non-carbon base for the development of 7 billion humans now and 9 billion in 2050, you have to convince now the less-developed societies that their well-being will be more affected by a future climate change due to the use of a certain quantity fossil rather than by a present socio-economic change due to the non-use of the same quantity of fossil, etc. For that purpose, proposals like ‘There will be more droughts, floods, species losses (and whatever you want)’ is a far too undefined threat, you need to specify the ‘more’ in question and translate it in a kind of human welfare equivalent. That is the IPCC WG2 and WG3 assignment, by the way. So, I hope these points have specified the way I interpret your article and the objections I formulated to it. To be clear, I strongly favour energy transitions toward non-carbon economy, with some constraining instruments to achieve that goal, but I don't think the 'obsession' of a particular (450 ppm) target is of real utility. I'm sure everybody here is already convinced that this concentration will be exceeded, so we need to understand more precisely why it will be, so as to prevent far higher concentrations in the future. We must not be fatalistic and w climate casualties is the sole argument for change (eg things like 'there will be megadroughts in the 2020s or 2030s, and then maybe humans will understand') PS : for more precise dilemma in the new era of climate negotiation, like the concrete Indian choices for 2012-2030, see for example my comments in the other thread about Global carbon emissions .
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  18. 67,,
    ...over-anthropomorphized nature...
    Anthropomorphization is a literary and rhetorical tool. Nothing more. I don't really think it can be "overdone" because it's niether good nor bad... it's just a writing style.
    ...the ultimate qualification of good/bad relies on human evaluation...
    If you believe this, then you really do not understand either the science or the implications. Please understand this, even a result that only takes us 1/4 of the way to the sort of change implied by my article will be very, very bad for a whole lot of people. Human beings adapt, but they do not deal well with adaptation. Adaptation means death and suffering. Resource pressures mean wars and suffering. Major, outwardly forced change means economic and social upheaval -- and suffering. Throughout human history this has been the case. If you actually believe climate change will be even remotely good for civilization or for most individuals, you need to study the science more and you need to think it through more completely. You are stopping at the obvious, easy, pleasant conclusion without getting all the way to the end. Man does not deal well with change. Climate change will mean suffering. There is no way around that.
    ...fossil-based development during the last two centuries is one of the most astonishing accomplishment in human history...
    Absolutely, yes! Industrialization advanced civilization and society by leaps and bounds, but at the same time it lead to the suffering of masses and masses of people in the 18th century. It was a good thing that came with a lot of evil. Fossil fuels (and other advanced technologies) freed us from much of that burden. There is no question that the use of fossil fuels for the past century were a tremendous boon to quality of life and the advancement of our civilization. It does not, however, logically follow that we must then insanely follow that course to the point where it damages or even destroys the very same civilization that it advanced.
    ...fundamentally, I believe economy and society depends on their energy basis...
    Absolutely, yes. But that basis can no longer be fossil fuels. Unfortunately, the investment and infrastructure for fossil fuels is so entrenched in our civilization that it will take many decades to replace it all... unless we try to do so in a too-rapidly painful way that will be as disruptive as climate change itself. It will take a very long time to replace all of the power plants, engines, vehicles (cars/ships/planes), fuel-transport systems and more. But replacement is ultimately necessary anyway, because machines age and require replacement. It's just a question of what you replace it with, starting soon enough, and having viable things to use in their stead (such as hybrid cars, which have been readily available for a decade and yet are woefully uncommon on the roads). And that's why we have to start now, and that's why people who now say (this is you) "it may not be bad" or "it's not happening" or "we can't afford to change" are only making the problem far, far worse than it already is or needs to be. The world does not need more excuses to fly someone across the ocean for a 1-hour meeting (my brother used to do that regularly), or to drive 3-ton SUVs 1 mile to the store to pick up one loaf of bread after that loaf was baked 500 miles away using grain that was grown 1,000 miles from there, only to throw away half of the loaf because it got a little stale, all using an energy source that we know is (a) near exhaustion and (b) dangerously dirty... it's insanity!!!!
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  19. Sphaerica : Absolutely, yes. But that basis can no longer be fossil fuels. Unfortunately, the investment and infrastructure for fossil fuels is so entrenched in our civilization that it will take many decades to replace it all... unless we try to do so in a too-rapidly painful way that will be as disruptive as climate change itself. Oh nice, we perfectly agree on that and so was my main point ! When you speak of a ‘painful’ and ‘disruptive’ decarbonization, that is exactly what I mean by ‘human evaluation of climate change’. You accept the fact that a part of the climate change is tolerable because a too abrupt energy change would be comparatively less tolerable. By doing so, you evaluate what is (more or less) good or bad for human society exactly as I suggest we should do. This does’nt mean you consider climate change as good in itself, but better (or not worse if you prefer) than an abrupt energy shortage. About climate, you’re projecting death and suffering in a possible and future world, but when it comes to human welfare, I’m personally speaking of death and suffering in our present and real world, for which certainty is 100% from observations, not X% from models. I confess that I‘m suspicious (and often irritated) toward climate-centered views that seem to ignore or relativize the other problems of humanity, the orders of magnitude of human needs in our world, the potentially damaging conflict between climate goals and energy supply, as I gave a concrete example with Indian dilemmas after Durban. But if your position is a realistic one, as it seems to be with this quote, there’s no problem : we agree. When it comes to solution, you must note that even if OECD divides by two its carbon emissions, what I hope we’ll do as fast at possible but what will already be a great challenge, this leave us with a 2 PgC decrease each year : but this quantity is what is henceforth added to annual emissions from developing countries in less than 10 years (see Peters et al 2011 in the carbon discussion) and this development is just the beginning of the great leap forward modernization of their societies. So let’s be clear : if we don’t want a ‘disruptive’ and ‘painful’ carbon plan, it will be very difficult to prevent a CO2 doubling. That’s why the very first priority is to ease the access to non-carbon energy everywhere it is possible, to reinforce the R&D in that domain and before all to price carbon externalities so as to give the good signal and improve RE competitiveness. At least I prefer this kind of clear way that to lose precious years with discussions around an unrealistic world 450 ppm target, not even mentioning the 350 ppm Hansenian ideal. PS : You point out the risk of fossil ‘near exhaustion’ : I suggest this could be another very good argument for a huge effort in decarbonization – and perhaps the future deus ex machina for a rapid (but if so difficult) energy transition. Tom Curtis seems to be very optimistic about fossil reserves, when suggesting in #44 we’ve enough for CO2 4600 ppmv, and CO2 1000 ppmv in this century. These ‘geologic’ quantities from USGS Survey (or ‘cornucopian’ estimates of Lomborg’s style) are IMO far from the real quantities we can extract and use at a sustainable cost for our economy. But we'll check that point well before 2050, or even 2030.
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  20. 69,, I want to find some common ground, but you're putting words into my mouth, or at best over-interpreting what I am saying. Specifically, I do not "accept the fact that a part of the climate change is tolerable". I simply accept the reality that too an abrupt a transition from fossil fuel use would be just as intolerable as climate change. What I do not agree with at all, however, is your seemingly blasé and sluggish attitude towards getting started. Forgive me if I am misinterpreting your attitude, but "the very first priority is ... to reinforce the R&D..." is exactly my problem. This is an excuse for doing nothing else, for waiting while fossil-fuel magnates make trillions of dollars and the clock ticks ominously. R&D, yes. Application of available clean technologies on a much broader scale, right now, yes. Quick and meaningful changes in societal and individual behavior against grotesque and unnecessary waste, yes. And none of these solutions would in any way damage economies. They would help economies. They would mostly create jobs. But the profits would shift away from national and global conglomerates and into the hands of the people that actually do most of the work, because you'd be eliminating that international middleman that packages and transports the goods thousands of miles across continents for little reason other than the fact that it seems to be cheap... but it appears cheap because the externalities of the expenses are not applied now, to the transaction at hand. That is left to you and I to pay ten, twenty or fifty years down the road. But it's not that the expense isn't there. It just isn't obvious yet. It's rather like one of those deals with the devil where the poor guy is all shocked and upset when the devil shows up at the end to collect. The USA is abysmally behind in every possible tangible approach to the problem. In the USA, it is very rare to see a car more than 10 years old. If people had been serious about the problem, 80% of the personal vehicles in the USA could already be hybrids, just as a matter of people having purchased them as they retired their old vehicles, and this could have come with accompanying advances in the transportation of goods and a reduction in costs due to mass production and volume. But people aren't serious about doing things. They want to do what you propose, which is to pretend to invest in R&D. What they'd like is for scientists and engineers to work for decades on finding easy, painless, and virtually expense-free solutions so that they can keep living their lives in oblivious — but expensive — bliss. That may not be what you intend, but it is the ultimate outcome of your position and your attitude. You can say that you want action — but do nothing of meaning for far too long. And if you wait, you will find that both climate change and the economic catastrophe that you so fear will both fall upon you at the same time.
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  21. #70 Sphaerica : one step back ! Clearly, we disagree. Forgive me if I am misinterpreting your attitude, but "the very first priority is ... to reinforce the R&D..." is exactly my problem. I also write just after : and before all to price carbon externalities so as to give the good signal and improve RE competitiveness. So, unless my English is still more incorrect than I imagine, you retain what you mostly disagree with, but you do not correctly represent what I wrote. (As a citizen of UE, I’ve no problem with high tax on gasoline, Kyoto, etc. we have an energy-climate plan for 2050 with a first step in 2020 and the ultimate target of 1 tCO2/c/y. Your concerns for inaction in my case are strawman, and I would add that I personally and already produce less than 1tCO2 each year). For R&D, it is a urgent necessity because RE have quite poor energy and power densities, storage, etc. They are not sufficient in their current technologies for providing enough energy to the world in 2050 (best estimate of RE in the mix in 2050 : 250 EJ/y according to median value of IPCC SRREX 2011 scenarios, current production approx. 500 EJ/y). Facts are stubborn things, that’s true for climate, that’s true for energy too. Specifically, I do not "accept the fact that a part of the climate change is tolerable". De facto, you accept this situation if not you would simply require the global prohibition of fossil extraction. It is by far the simplest solution of you want to stop carbon emissions and climate change induced by the emissions. If you tell me that fossil prohibition would have too many adverse effects, it means that you implicitly prefer a fossil-fuelled world with a changing climate than a non fossil-fuelled world with a stabilizing climate. So do I, but I’m coherent and I explain my position, or at least I try. For the rest, I’m all but at ease with your discourse. Peters et al 2011 graph is crystal clear : 7 billion people need fossil energy, and mainly the poorest 5 billion that engaged recently in development and that are responsible of nearly all the 49% increase of emissions from 1990 to 2010 (the poorest among the poorest haven’t been involved in these emissions, and for this reason among others, their quality of life is generally tragic). A discourse that doesn’t address precisely this reality and doesn’t explain how to deal with these energy needs is a dangerous discourse, the fact that it pretends to avoid another danger doesn’t make it less dangerous. Indian citizens are basically unconcerned by US wastes, they have a mean 25 GJ per capita per year and a decent quality of life would imply rather 75 GJ (US citizens have 330 GJ, you observe that my target is far from imitating Western wasteful way of life). So, unless you explain precisely (not with effortless rhetoric on ‘magnats’) how to produce this energy without the abundant coal in India ground, you cannot have the lesser hope for a drastic change in carbon emissions. And secondarily (forgive me if I misinterpret you attitude), you cannot convince me that you’re really interested in the development of the second and the third world.
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  22. 71,, Apologies. I read "and before all to price carbon externalities" as meaning do R&D before any carbon pricing schemes, when I think you are saying you meant to do the carbon pricing first. It would have been more clear (more common phrasing) if you had said "but before that to price carbon externalities." Still, my apologies for misunderstanding. On everything else... this is really all OT concerning the original post, but you are painting two extremes as the only options, either get off fossil fuels instantly, or stay addicted in an effort to turn the second and third worlds into carbon copies of the first. Both paths are paths to ruin. My position is that 451 ppm is far more dangerous than people admit. We cannot go cold turkey off of fossil fuels, but we don't have to, and we're currently not trying in the slightest to do anything at all. We will never live in a world where 7 billion people live like American citizens do today, and any attempt to do so guarantees that we will massively exceed 451 ppm, with an end result that is to horrible to contemplate. Fast, immediate but moderate and considered action is the only viable course, with the necessary goal being sustainable economies and cultures globally, whatever sacrifices that may ultimately entail. Our current track — ignoring the problem — is destined to end badly.
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  23. Going back to Sphaerica's list # 23 of countries that may win/loose from warming consider the following mix: Pakistan is vulnerable to changes in Monsoon patterns and glacial melt reducing river flows - OK, not by 2035. And they have Nuclear Weapons. India is just as vulnerable as Pakistan and they are on track to be the Earth's most populace country. And they are churning through their groundwater resources at an impossible rate - pumping water from 1 kiolmeter underground while some farmers stop growing food and just sell water because the government subsidises pumps and electricity. And they are Nuclear Armed. China basically subsists on Rice from its south & wheat from its north. The Yiangtse produces 1/2 China's rice crop. And you guessed it. Its sources are Himalayan Glaciers and Monsoonal rains. In Norther China rivers have a bad habit of not reaching the sea. And they are fed by Glaciers. And much of the wheat grown across the plains of Northern China is irrigated by ground water that is also declining. Unlike India where if they just stopped using groundwater for a few decades (and stopped eating for the same period) their aquifers would recharge, the aquifers of Northern China take centuries to recharge. And China has Nuclear Weapons too. Then to the North there is Russia, and all the expanses of Siberia. Currently Birch Forest, Tundra and Permafrost. But with warming, it starts to bloom (if you can ignore the fact that much of the soils are acid). And Russia is Nuclear Armed. And the population of Siberia is definitely not Asian, and has a long history of being provincial and quite parochial (Fiddler on the Roof is actually a story about the marginalised in rural Russia). So lets let AGW start to mess things around and play geo-politics. Is India stealing Pakistans water as Pakistanis starve? What will the people of Eastern India think about the idea of moving into the fertile areas of China like Szechuan? Maybe starving Northern Chinese will start to wonder what a few 100 million good chinese peasant farmers could do with all that birch forest and tundra - we can grow rice anywhere if we try. Imagins your average Siberian russian welcoming columns of Han Chinese 'immigrants' onto their land. And all these people will expect their governments to support them. If those governments aren't leading the push. Who pushes the red button first. Or maybe it is just the old fashioned method - when America was going through the agony of its civil war, thinking that 500,000 dead was a horror, at the same time in China, the Taiping Rebellion saw 20,000,000 dead. The old fashioned ways always work. But if someone does push the button - old books about Nuclear Winters with titles like 'The Cold & The Dark' may suddenly gain currency. Global Warming would immediately be on hold. Till the smoke and dust settles. Then it comes back with a vengeance, thanks to all those burning Birch Forests and Peat pumping out CO2. And in such a world, how is everyones mental health doing? No matter what the climate/environmental consequences may be, the Social/Political/Military/Psychological consequences will likely magnify all of this.
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  24. #72 Spaherica : apologies accepted… but in fact probably undue, as you mention, my English is confusing and so was probably the expression of my priorities for carbon mitigation. I agree that a sustainable future is still to be invented, for carbon cycle, water cycle, nitrogen cycle and more broadly the ecosystem services that we’re disrupting too fastly and too profoundly. The same is true for inequality between the North and the South, or the 10% and the 90%, but it would be OT to continue on that matter. #73 Glenn Tamblyn : there are many motives of conflict between nuclear armed countries. And don’t forget that in the worst recent genocide (Rwanda 1994), sophisticated weapons were not required, the ‘primitive’ machete killed hundred of thousands. Your point is true for climate (example of risks associated with monsoon and glaciers melting in overcrowded countries) but notice it is also true for all abrupt changes in human societies : that’s why the precautionary principle must not be adressed to one problem in particular (climate), but to all known problems simultaneously. Food and water disruptions have probably always been the main threat for human societies (with disease), and this will remain true for the predictable future. Climate change will make the problem more difficult. See Godfray 2010 and Foley 2011 for recent analysis of the ‘9 billion feeding problem’ in a sustainable view. The good new is that solutions exist, the bad that they will be tough to implement. On that question, see also the interesting paper of Hsiang et al 2011 on ENSO-related civil conflict casualties (another example of climate change externality).
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  25. As for communication. Both Republicans and Democrats are more and more believe the theory of AGW - as reported by this report. We skeptics are (not only in the U.S.) "in retreat". I am skeptic, "a specific". I think that 9? % of the planned action - "fight" with AGW - are useful for us and the Earth. Why then the world has not accepted the "road map" postulated by the IPCC? Just lack of money. Extreme events. It is precisely analyze the latest IPCC document: part Climate extremes and impacts: “Global-scale trends in a specific extreme may be either more reliable (e.g., for temperature extremes) or less reliable (e.g., for droughts) than some regional-scale trends, depending on the geographical uniformity of the trends in the specific extreme.” “There is medium confidence that some regions of the world have experienced more intense and longer droughts, in particular in southern Europe and West Africa, but in some regions droughts have become less frequent, less intense, or shorter e.g., in central North America and northwestern Australia.” Amazonia. In former times warm - indeed savanna occupied much of the current tropical forests. Savannah in their biomass and soil contain only (on average) half of the carbon contained in tropical forests. It is, however still many more than analogy to deserts. In former times in the Holocene warm, savannah occupied areas of tropical and subtropical deserts the current in Africa and Asia. Savannah moved - as a result of climate change - hundreds of miles to the north and south of the equator. We do not need to use only models here. More and more is a paleo-studies and the results of scientific experiments. Eg. Françoise Gasse Sr. , CNRS-France, writes: “All data indicate an intensification of the monsoon and a northward migration of 500-600 km of the tropical rainfall belt.” „Between ca. 11.5-11 and 6-5 ka BP (early-mid Holocene), the Sahara was wet and green, with numerous lakes and rivers.” “Many records document, however, a short-term but marked arid event around 8.5-8 ka BP possibly linked to a minor cooling recorded in Greenland ice cores.” When we reach 451 ppmv of CO2 in the atmosphere? Unfortunately, we do not know - I recommend the text with extensive analysis of Nature: „Many lines of evidence show that the variations in the CO2 growth rate are mainly caused by terrestrial effects, in particular the impacts of heat and drought on the vegetation of western Amazonia and southeastern Asia, leading to ecosystem carbon losses through decreased vegetation productivity and/or increased respiration.” “On the other hand, the biological processes underlying respiration are assumed to respond to temperature in an exponential way but are not affected by the CO2 concentration ...” “The fundamental simplifying assumption behind this reasoning is that above-ground assimilatory processes (plant photosynthesis) and below-ground heterotrophic respiratory processes (for example, decomposition by fungi and respiration by animal and bacterial life in the soil) can be conceptually isolated and analysed separately. Although this conceptual model has provided valuable guidance for experimental and model design, evidence has accumulated in recent years that above- and below-ground processes are intimately linked, constituting a complex and dynamic system with non-negligible interactions. Hence, the situation is much more complicated than previously thought and might result in unexpected dynamics through interactions between physical, chemical and biological processes within the ecosystem — particularly in the soil.” “Unfortunately, empirical evidence for global carbon-cycle–climate interactions on the timescale pertinent to current global climate change, that is, decades to centuries, is much scarcer.”( dedicates this sentence critics M. Salby) “As long as there is no fundamental understanding of the processes involved, simulations of coupled carbon-cycle–climate models can only illustrate the importance of, but do not show, a conclusive picture of the multitude of possible carbon-cycle–climate system feedbacks.” - and < a href => this figure of the cited analysis. Uncertainty range is huge - about the same. As for methane. At present also its content in the atmosphere has risen before CO2. To explain the increase of methane in the atmosphere are not needed (since at least 55 million years) clathrates. I recommend this paper : “The methane isotope change accompanying the jump in concentration confirmed that the emission was not from clathrates, but from ecological sources such as wetlands.” Stocks of C in permafrost according to current estimates (up to 4-5 times higher than estimated for the 2009) completely enough ( 1, 2, 3, 4 , 5 ).
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  26. Glenn T#73: Exactly why's assertion and subsequent euphemisms of 'winners and losers' is not just total nonsense - it is very dangerous nonsense.
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  27. For sure, let’s oblige China, India, Pakistan, Russia and neighbors to leave / not exploit rapidly their coal, oil and gas so as to save climate by lowering emissions at 50% of their current level in one generation, because we (responsible citizens without nonsensical and dangerous ideas) are pretty sure this decision will necessarily reinforce peace, security and welfare for these nearly 3,5 billion citizens in 2050. It is well known climate is the only source of war, suffering and death in all human history, as it is well known energy and its correlates in society are just trivial details.
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  28. - Odd, I don't see a /sarcasm marking in your last post... Climate change is a slow-motion train in progress. Over the next 100-150 years with business as usual (BAU) we're looking at any number of consequences: * No summer ice in the Arctic - loss of albedo increasing heating rates, killing off polar bears, etc. * Loss of most of the Western US pine forests due to migrating pests (in my personal view a terrible shame). * Considerable reduction in crop productivity over much of the worlds currently developed agricultural lands (est. >50% loss in California Central Valley, source of 8% of US produce). * Ongoing conversion of the Amazon into savannah. * Ongoing rises in extreme heat events, droughts, floods. * Sea level rise - perhaps 1-2 meters, perhaps much more. * Loss (by submergence and erosion) of the majority of Pacific atoll islands. * Catastrophic loss of coral reefs (acidification, temperature rise) leading to major extinctions. * Probable collapse of ocean food productivity - see the various ocean acidification threads - as the base of the ocean food pyramid collapses. And these consequences hold whether warming rates are at the high or low end of current climate sensitivity estimates - only slight changes in how fast they hit. And yet - you seem to repeatedly call for "go slow" approaches, to minimize economic shifts or disruption, to 'tone down' the urgency. This despite the (acknowledged) lead time required to shift energy production from fossil fuels. When a train is approaching, it's perhaps wise to get off the tracks!
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  29. 75, Arkadiusz Semczyszak,
    Many lines of evidence show that the variations in the CO2 growth rate are mainly caused by terrestrial effects...
    Citation please. Otherwise this is mere assertion. Even with a citation... where do you propose all of the CO2 can be coming from, year after year, from "Nature." Your premise here is laughable. The CO2 "budget" is closed, and we know we are the cause and what the rate of incline is. To suggest that we don't know when we'll reach 451 ppm is downright laughable. Your supplied citation, on the otherhand, contradicts your own statements. The paper studies uncertainties in the continued uptake of CO2 by ecosystems, and the probability (as I stated in my post) that this uptake may reverse and instead release CO2. The opening line:
    Recent evidence suggests that, on a global scale, terrestrial ecosystems will provide a positive feedback in a warming world, albeit of uncertain magnitude.
    From the conclusion:
    Overall, it is likely that, at least on a global scale, terrestrial ecosystems will provide a positive, amplifying feedback in a warming world, albeit of uncertain magnitude.
    Your comments on methane are a non sequitur. As I already stated clearly in my post, there are obviously known differences between a glacial termination and our current situation. No one, anywhere, ever said that the methane feedbacks that we expect are in any way comparable to what was experienced in the last glacial termination, so the fact that the mechanisms are different makes no difference whatsoever. Really, Arkadiusz, you can do a better job of expressing complete and total denial than this.
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  30. #78 KR : I write here on a web site called Skeptical Science. As Stephen Schneider once nicely put it in his famous reflexion about the 'double ethical bind', "as scientists we are ethically bound to the scientific method, in effect promising to tell the truth, the whole truth, and nothing but — which means that we must include all the doubts, the caveats, the ifs, ands, and buts." (my underscore) So either SkS is bound to this scientific ethic, and for the long list of climate effect you mention (or Sphaerica in his text), it must also be precised the doubts, caveats, ifs, ands, buts. Or SkS is bound to a layman / militant ethic, and then it is ruled by the second part of Schneider quote : "On the other hand, we are not just scientists but human beings as well. And like most people we'd like to see the world a better place, which in this context translates into our working to reduce the risk of potentially disastrous climatic change. To do that we need to get some broadbased support, to capture the public's imagination. That, of course, entails getting loads of media coverage. So we have to offer up scary scenarios, make simplified, dramatic statements, and make little mention of any doubts we might have." (my underscore). I already gave some precise examples for the Sphaerica 451 ppm world, notably the Fire Age metaphor that is not supported by vegetation-AOCM coupled model on a global scale and is misleading as such, without precision that the "fire" in question concerns some regions (and usually not at 451 ppm concentration in literature, rather a doubling CO2 a minima for model projections ; if I recall correctly 451 ppm is even under the SRES B1 concentration in 2100, and best estimate of the transient sensitivity for such forcing is quite low). And there are others. If you read carefully climate literature, you perfectly know that there is still divergence among AOGCMs on the amplitude and frequency of changes related to precipitation and temperature, and it is even more true for regional projections. Climate science is not just made of Hansen or Rahmstorf papers (whatever their quality), that's why IPCC exists. So, if you speak of droughts, you must recall that IPCC SREX 2011 just give of "medium confidence" for their increase ; if you speak of crops productivity, you must recall that IPCC AR4 WG2 suggest it will continue to increase with a 1-2K warming on low latitude and a 1-3K warming in high latitude, and that, with medium confidence, 'the marginal increase in the number of people at risk of hunger due to climate change must be viewed within the overall large reductions due to socio-economic development' (chapter 5). And so on. These are the 'buts', 'ifs', 'ands' of Schneider's scientific ethic. From an ethical stance, I can no more accept a 'end justify the means' approach, which is implicit in many critics of my position including yours. From a pragmatic stance, I observe the 'doom and gloom communication' strategy is a failure, either for changing personal / societal behaviors or to engage a world policy at successive COPs. These are two sufficient reasons to explain my point. Maybe some here are very happy to reiterate each year the game of COP hope-followed-by-delusion, I'm not. Maybe some here are happy with eternal complaining about 'human-selfishness-that-ignore-the-bad-consequence-of-his-action', without any perceptible effect on the selfishness in question, I'm not. I added a third point : human welfare is my ultimate concern, I don't think a climate-centered assessment of risk on this welfare is fair as we all know that climate mitigation is causally bound to fossil energy limitation. 'Euphemisms' (muoncounter) are everywhere in this debate: in current technology (no CCS available), the only method for not exceeding 450 ppm is to fix now a maximal quantity of fossil for each country and to forbid its use beyond this limit, including many non-OECD countries. Do you want that, yes or not? If yes, I tend to think that you defend a dangerous target for humanity, at least I wait a strong justification that adverse effects of a constrained energy shortage will not be more harmful that adverse effects of the avoided level of climate change. If not, you're probably somewhere in my zone of interrogation: what are the better solutions to promote now (and not in 2020, 2030, etc.)? As I already suggested, my fear is that the 2K/450 ppm target is a Pyrrhic victory for those who are interested in climate mitigation. I foresee a stagnation of climate diplomacy which ultimately profits to the "business as usual" scenario. Sphaerica insistance on the 451 ppm world seems to me a caution to this very likely failure. Maybe I'm totally wrong, maybe 194 countries will adopt without problem the post-Kyoto treaty in 2015, maybe energy transition will be easy and no country will abandon the treaty as some did for Kyoto.... In one sense, I hope so, but I've no rational argument to justify such a hope.
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  31. - "From an ethical stance, I can no more accept a 'end justify the means' approach, which is implicit in many critics of my position including yours." I would have to disagree most strongly with your interpretation, I do not believe I have ever stated anything of the sort, and consider that an unjustified Strawman distortion. My position is that climate change has significant, negative impacts, that addressing emissions will not cost too much, and will in fact actually save money over the mid to long term. And from that, that any delay in addressing CO2 emissions and climate change increases the cost of dealing with it. That doesn't by any means justify making stuff up, or running around like Chicken Little. But it certainly means being very clear what the range of likely climate impacts and costs are when discussing the matter. I would agree that drawing lines in the sand, lines that (given the observed intransigence of the fossil fuel industry and conservative politicians) are likely to be crossed - that is perhaps not terribly productive. But neither is soft-pedaling the cost of not acting, which appears to be what you would prefer (here, here, here, for example).
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  32. 80,, I am now officially beginning to tire of the latest denial tactic, which is to purport to have this huge interest in the welfare of the poor in third world countries, and that the only humanitarian way out for them is through more and more and more use of fossil fuels. You complain that my "fire age" metaphor is a scare tactic, and then calmly resort to the same by over and over implying that anything less than wanton, remorseless use of fossil fuels to lift the third world countries from the sludge would be a crime against humanity. Then you say there are lots of uncertainties in the science. Then you imply that fear-mongering is the business of certain climate scientists. Your words (and anyone here is free to go back and review them) call for delay, delay, delay for any reason you can think of — we're not sure, they're fear-mongering, it will hurt the poor. You seemingly want to mollify your conscience by saying you are in favor of pricing carbon externalities, and yet 99% of your words instead say "do nothing." I think you need to stop pontificating, state clear priorities and goals, and then start generating comments that are actually in line with those goals, rather than generating whatever stream of comments will help you arrive at the same, tired conclusion that "we really should wait on this whole get-off-of-fossil-fuels thing."
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  33. #81 KR : OK, my apologies for the misinterpretation of your sentence : "And yet - you seem to repeatedly call for "go slow" approaches, to minimize economic shifts or disruption, to 'tone down' the urgency. This despite the (acknowledged) lead time required to shift energy production from fossil fuels." It sounds to me as if I was supposed to leave or silence all my doubts because of a urgency to act. But it was not your thought, so sorry. "given the observed intransigence of the fossil fuel industry and conservative politicians" No. Like the Sphaerica's "magnats", this is a typical misinterpretation of reality. Look at Peters et al 2011 article I already quoted, nearly all the increase of CO2 emissions since 1990 come from non-OECD countries who're escaping poverty. And so for the projected decades, as IEA WEO 2011 put it : "The dynamics of energy markets are increasingly determined by countries outside the OECD. Non-OECD countries account for 90% of population growth, 70% of the increase in economic output and 90% of energy demand growth over the period from 2010 to 2035." So even if the last 15 years US blockage to climate decision is a pity, partly due to lobbies, you should IMO leave this Western-centric view of the energy-climate problem for the future, because even US is henceforth a small part of this problem. (At least, carbon intensity of US economy made small progress, this is not at all the case when a poor country begins its development.) In real choices for developing countries, the problem is not the fossil fuel industry (not speaking of Western conservatives), it is the incapacity of wind and solar industries in their current technologies to provide the regular, large and if possible cheap basis for an energy infrastructure needed at a national scale. And also to provide fuel for transportation, of course. BRICs and other developing countries are not foolish, if non-fossil solutions were the most interesting for their energy mix, their would have chosen this way for a long time: no pollution, no dependency of foreign providers, no climate warming... # 82 Sphaerica : the French expression for your repeated claim is "procès d'intention", I don't know the English counterpart. I'm tired too. But I think I have now a clearer idea of how skeptic is "Skeptical" Science. Readers will appreciate how clearly my different points and concerns have been answered here.
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  34. - Side note: I can understand being tired of a particular discussion, but I do not believe that excuses the rather snarky tone of your post. Yes, most increases are coming from developing nations. But currently the 10 largest emitters (here, pg. 13) are in order China, the US, India, Russia, Japan, Germany, Iran, Canada, Korea, and the UK - together accounting for >65% of world emissions. Action by these nations (most of which _cannot_ be considered to be 'developing nations') can have significant effects on the rate of climate change. China has some of the largest investments in renewables in the world. In the US wind and solar are the fastest growing segments of the energy market - hardly an indication of lacking economic viability. In regards to baseline power (somewhat off-topic here), I would suggest looking at (and commenting upon) the Can renewables provide baseload power thread, where this myth is discussed. Considering fossil fuel 'cheap' power depends on ignoring the real, total costs of fossil fuels - including the external costs. Costs that will be paid by all (including developing nations) regardless of your accounting. Developing nations are growing rapidly, and will be an increasing part of the issue - but not yet. Hmm... wouldn't it be a good idea to head the problem off, and work together to minimize the high growth developing nation energy use impact on climate change? Helping all to create new power systems, increasing power availability, that don't pollute? Rather than throwing ones hands in the air, claiming (as you have) that limiting fossil fuel usage will crush developing nations? I think renewable energy development can be a definite win-win scenario. It unfortunately represents a redistribution of wealth away from some vested interests, who are spending rather large sums lobbying for Business As Usual, along with ideological interests who feel that any regulation of even potential freedoms for the common good is untenable - the situation here, at least, in the US. From that come the 'skeptics', pushing inconsistent and contradictory hypotheses that don't account for the facts, and from that come things like RealClimate and SkS - where the facts are (as best they can be) discussed. --- And yes, I would agree with you that "Readers will appreciate how clearly my different points and concerns have been answered here". Although I expect that my opinion on their reactions will differ from yours...
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  35. 83,,
    But I think I have now a clearer idea of how skeptic is "Skeptical" Science.
    Let's see. Some people disagree with you, and say that you have failed to make a coherent point, therefore this entire web site dedicated to presenting and clarifying the science is disingenuous. Yes, that makes sense. And your agenda is now crystal clear to everyone.
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  36. KR-
    It unfortunately represents a redistribution of wealth away from some vested interests, who are spending rather large sums lobbying for Business As Usual...
    It needn't be that way,in my view,if those vested interests would throw their considerable capital investment power behind alternative energy development.That way they can immediately drop their disinformation campaign,and keep all that money that they are funneling to politicians and advocacy groups,and go full bore into a cleaner future,and a safer world for themselves,their children,and grandchildren,and be genuinely proud of the business that they are in,instead of having to manufacture artificial advocacy using deceitful tactics.
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  37. #84 KR But currently the 10 largest emitters (here, pg. 13) are in order China, the US, India, Russia, Japan, Germany, Iran, Canada, Korea, and the UK - together accounting for >65% of world emissions. Your count adds apple (USA, Japan) and orange (India, China), not all these countries have the same real GDP per capita! Look at Peters et al 2011 figure for a comparison of developed and developing country. And above all, loo at the curve, one linear and flat, the other exponential and up. By the way, here in Europe we accept our historical responsibility and we're committed to GHG cuts, even if there is no international agreement in this sense. Considering fossil fuel 'cheap' power depends on ignoring the real, total costs of fossil fuels - including the external costs. That is exactly what I say. And so, why we do not implement immediately a global carbon tax, that is what I called "pricing carbon externalities"? It is very easy to implement (directly on coal, gas and oil producers, or deforesters) and quite easy to adapt (part of the tax will help specifically low and medium GDP countries that will be more affected by higher prices). (-Snip-) Rather than throwing ones hands in the air, claiming (as you have) that limiting fossil fuel usage will crush developing nations? When South Africa open a mega coal plant in 2010, the point of its policymakers is clear : “To sustain the growth rates we need to create jobs, we have no choice but to build new generating capacity — relying on what, for now, remains our most abundant and affordable energy source: coal.” What you call "my" claim is just what South-African, Indian, Chinese and other climate-energy plans are claiming, the escape of poverty will not be sacrificed. For example in the Chinese's National Climate Change Program, you can read : In the development history of human beings, there is no precedent where a high per capita GDP is achieved with low per capita energy consumption. With its ongoing economic development, China will inevitably be confronted with growing energy consumption and CO2 emissions. (…) To place equal emphasis on both mitigation and adaptation. Mitigation and adaptation are integral components of the strategy to cope with climate change. For developing countries, mitigation is a long and arduous challenge while adaptation to climate change is a more present and imminent task. China will strengthen its policy guidance for energy conservation and energy structure optimization to make efforts to control its greenhouse gas emissions. Meanwhile, China will take practical measures to enhance its capacity to adapt to climate change via key projects for ecosystem protection, disaster prevention and reduction and other key infrastructure construction » So if you understand the diplomatic language, beside the fuzzy promises of future effort for decarbonization, it means : mitigation is not our priority. (-Snip-) I think renewable energy development can be a definite win-win scenario I already gave above the numbers from IPCC SRREN 2011 concerning real capacities of RE in 2050 according to the median estimate of energy-economy scenarios. So you have to be specific : in a 450 ppm target in 2050, RE are planned to likely produce something like 250EJ/y, half of what we need now for 7 billion (500 EJ), not to say what we will need tomorrow for 9 billion. If you personally think that RE will produce 500 EJ or 750 EJ in 2050, you’ve to explain why the majority of 164 IPPC scenarios does not produce at all such a quantity. (-Snip-) #85 Sphaerica Some people disagree with you, and say that you have failed to make a coherent point, therefore this entire web site dedicated to presenting and clarifying the science is disingenuous. You're right. I clearly doubt your skepticism.
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    [DB] Inflammatory, political and argumentative snipped.  Please acquaint yourself with the Comments Policy of this venue.  And do also please attempt to ameliorate the inflammatory tone. 

    Modeling that which you seek others to emulate is best (good advice to all).

  38. @83, I am very disturbed by your repeated attempt to position the various authors and comentors at Skeptical Science as being insufficiently skeptical. It calls into question the bona fides of your entire discussion. It seems to me that what is missing from your discussion is two crucial perspectives. The first is simply time. It takes time to transition from a high carbon to a low or zero carbon economy. With the best will in the world it could not be done in less than twenty years, and ideally it would be phased in over 40 to 50 years (ie, through the natural cycle of replacement of obsolete power plants). Anything faster incurs significant increased costs. Given that a thirty year transition to a low carbon economy already commits us to around a trillion tonnes of cumulative emissions, and hence to a 50% probability of a 2 degree C rise over the preindustrial average, that already represents a problem. There are of course, caveats. We may get lucky and climate sensitivity may be in the lower half of the IPCC range, in which case we may have 40 rather than 30 years to make that transition. Of course, an equally important caveat which you neglect entirely is that the climate sensitivity may be in the upper half of the IPCC range, meaning that even with our best efforts we are looking at 2.5 to 3 degree increases. In other words, the risk we face with determined action against climate change is that we are already to late to stop a change in climate which will significantly reduce future agricultural productivity. As it happens, we are not making our best efforts. The world as a whole has reluctantly agreed that they should talk about making an agreement that they will consider signing in 6 years and which will come into effect in 9 years. In the meantime several major emitters (including the second, third and fourth largest) will accept no significant reduction targets, nor even significant carbon intensity targets. That means we are facing 10 years of increasing growth of emissions, which means that by 2020, to meet the 2 degree C target that is considered safe, we will not have 20 years in which to act, but 10 or less. What that means in practical terms is that instead of a 1-3 degree probable warming range, we are now looking at a 2 to 4 degree warming range if an effective agreement is implemented in 2020, an assumption that requires rampant optimism. In other words we are already on target for probable levels of warming that even you acknowledge as dangerous. If you like analogies, we are in a car approaching a solid looking wall. We do not know if the wall is far enough away for us to break in time or not. Nor do we know if it is solid enough that our car will be completely destroyed, or merely severely damaged. Our response, in the face of this uncertainty has been to step on the accelerator. The second perspective you appear to lack is that the current policy response is well below that recommended by all the various balanced studies that look at exactly this issue and which show that on balance, mitigation preserves a higher proportion of future economic growth than does adaption alone. Current policy response is behind the curve of recommended action, based on all the caveats. It is not ahead of it. So while you can glibly quote Schneider about the nature of scientific skepticism, it is you who are ignoring the caveats that should be on your position, rather than we that are ignoring those on ours. I have not seen any caveats from you about the likely effects of rising fossil fuel prices (especially petroleum products)in the near future. On your logic, which with I agree, that represents a massive risk to the welfare of future generations. It is, however, a risk that is significantly reduced by a transition to a low carbon economy. Nor have I seen your caveats about the relative importance of energy to well being (or is that thesis sacrosanct for you, and beyond disputation). I agree that energy is important for development, but that is not a tautology. Finally, your "caveats" on renewable energy have a catastrophic strain that is unsupportable. The standard of economic well being in 1950's USA was very high even by current world standards. Yet it was sustained at an energy cost far below that of the current economy. Given known economics of commercial solar and wind power stations, that standard of living could certainly be maintain that 1950's standard of living. Remember, the dispute about renewables is not whether they can produce commercial power, but whether they can produce enough to maintain current, Western standards of living. If they fail at that, they do not maintain nothing, but a standard 5 or 10% lower than current Western standards. While not ideal, an increase of third world standards of living only to the level of 1950's USA, and a (slow) retreat of Western standards to that level is no catastrophe. In light of this, you are failing to see the caveats implicit in the positions of your debating partners only because you have not placed appropriate caveats on your own objections.
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  39. @87:
    "But here it is, we have the faaaaamous 2K/450ppm target, at least 9 years of bureaucratic diplomacy open to all the lobby influences. Bravo!"
    Are you suggesting, perhaps, that we should adopt Hansen's scientifically supported target of 350 ppmv? No, of course not. A caveat that Hansen may be right goes in the wrong direction for you, and is consequently ignored. If you had paid any attention to it, you would not be so sarcastic about a 450 ppmv target. Your sarcasm, however, captures perfectly how one sided your skepticism is.
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  40. Tom Curtis: Having followed this comment thread from the get-go, I believe skept fr ‘s posts suggest that he/she is a disciple of Bjorn Lomberg.
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  41. #88 Tom, please to read you here. 1) Although a layman, I myself always question my own skepticism, because I know our judgements (including mine) are so easily biased by poor information, prejudices, emotions, beliefs, etc. And I’m happy your critics drive me to such a questioning. But that is critics, not strawman about my supposed hidden goals. I hope you make the difference and you understand why, for my part, I doubt the bona fides of some of my interlocutors. 2) I do not neglect the caveat that climate sensitivity may be high, I’ve strictly no idea about that and I believe what models produce. We’re obliged to do so, AOGCMs and tomorrow Earth System Models are our sole instrument for such projections. Paleoclimates do not guarantee that CS in past conditions is the same that CS in current conditions, as it has been acknowledged in Schmittner et al discussion (for example on Real Climate). We are obliged to take decision under uncertainty : I consider the best choice is to rely on what models consider as their best estimate (eg 3 K). Of course, you can choose a lower or higher estimate. It depends on the perception of risk. If the choice of the higher sensitivity was cost-free and risk-free, it would be the most rational solution. But it is not, so the higher you choose a sensitivity, the more rigourous and precise you must be to estimate and justify the cost / risk that are the consequences of your choice. 3) I consider all level of warming as potentially ‘dangerous’, I’ve no reason to invent a treshold that would separate a dangerous and a non-dangerous warming (the same would be true for cooling, by the way). I don’t think the 2 K value has a sense, it’s purely conventional and IPCC never defined this value (it is recognized as a political choice, as the definition of 'dangerous' is not a scientific task). So, the less we warm the atmosphere, the ocean and the surface, the better it is. But I add : as long as the effort to lessen warming doesn’t produce more harm than it prevents. And here is the Gordian knot of our discussion : I don’t want a vague description of what is ‘dangerous’, I want a costs-benefits analysis of climate change compared to energy-economy change. My demand has nothing to do with denialism, and by no way it should be considered as particularly strange : Stern, Nordhaus, Tol and many other scholars are working on this question, in these terms. Maybe you dislike CB analysis, but as you know I’m a consequentialist, you won’t be surprised by this kind of request. 4) I dislike analogies and try to avoid them. But yours is interesting. You speak of a car (neutral) and a wall (harm). Your analogy is uncorrect as there is no cost to avoid the wall : the motorist is just stupid. In fact, a correct analogy would be something like : I’ve a house and I’m very attached to it, but there are floods threatening it and some suggest there could even be a tsunami. At which conditions must I leave my house for another one ? Here you have a real choice with costs on the two sides. And in real life, if you're obliged to leave your house, I bet you'll very strictly examine the details of the assertion about floods and tsunami, and the possibility to protect your house without leaving it. 5) I do not lack at all your second caveat concerning the fact that our current policies are not coherent (and in retreat) with the goal they defined themselves (remember the 2K/450 is a policy goal, not scientific one, point 3). In fact, it is precisely what I show : we clearly act as if the fossil benefits far outweigh the climate costs. Some say we do so because of lobbies, of conservatives, etc. I don’t agree with these kind of explanation, as I explained and illustrated by some examples. I suggest we act in this sense for many reasons, some bad (eg incapacity to project in the future, discount rate favorable to short term, 'know-nothing' and denialism of AGW, etc.) and some good (eg produce the material condition of decent life, create and trasmit wealth to future generations, etc.) 6) The rising price of fossil fuel is not a particular caveat of my position and it is a strange argument for those who want to increase by a mean or another the carbon price (by tax or by cap-and-trade like Kyoto). In fact, rising price of fossil fuels is a caveat of most SRES or RCP pathways, because none of them consider there could be a massive shortage in fossil supply during all the 21th century. It is a well-known critics of IPCC from Peak Oil defenders (like Jean Laherrère). This argument (I suppose against my position) is all the more so strange that a) I do not specially favor an inertial position on RE energy, because it is already competitive and would be more with a carbon price, and b) the example I gave for fossil fuels mainly concerned the ethical choices for less developed countries that have fossil fuel as a national ressource (India, South Africa, China, etc.). There are immune to great changes in fossil price if they exploit their own reserves. 7) The relative importance of energy to well being is not a sacrosanct point for me. It is an empirical observation we alreday discuss here on SkS and I’m totally open to a debate about that. If you show me a low energy period or country that could be reasonably considered as a model of welfare and a desirable example for policymakers and citizens, I would be happy to examine this case. Precision : the period or country in question should be on an enough long term to judge the diverse aspect and evolution of the quality of life. (For example, Cuba since the end of Soviet oil is a too short period, that is a classically bad example because all infrastructures of Cuba had been fossil-fuelled and we don’t know if the post-fossil Cuba will manage the replacement and modernization). 8) I think you have not the orders of magnitude in mind when you speak of the 1950’s USA standard as a universal goal. I’ve not the precise number for 1950 but as you can see on this graph , 1960 energy per capita was 5,5 tep. To be conservative, let’s imagine 3 tep in 1950, ten years before (in fact, the form of the curve suggest it should be more, probably 5 tep). 3 tep equals 126 GJ/c/y. A globalization of that condition would imply, for 8 billion persons (2030-2050), a 1008 EJ/y production. Of course, no energy scenario imagine such a high production, twice more than now. And certainly not without a huge part of fossil.
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  42. - "And so, why we do not implement immediately a global carbon tax, that is what I called "pricing carbon externalities"? It is very easy to implement (directly on coal, gas and oil producers, or deforesters) and quite easy to adapt (part of the tax will help specifically low and medium GDP countries that will be more affected by higher prices)." (emphasis added) I would, and do, support that. It's unfortunate that conservative ideologies (anti-tax) refuse to even consider this as a possibility. Hence (as an important note) my concern for informing such folks of the consequences of their (in)actions...
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  43. #89 Tom Are you suggesting, perhaps, that we should adopt Hansen's scientifically supported target of 350 ppmv? No, of course not. A caveat that Hansen may be right goes in the wrong direction for you, and is consequently ignored. If you had paid any attention to it, you would not be so sarcastic about a 450 ppmv target. Your sarcasm, however, captures perfectly how one sided your skepticism is. I haven’t seen this point. Again, we can choose a 350ppm, a 450ppm, a 550ppm target... this is ultimately a policy choice of what we, humans, define as a level of climate change we can tolerate when we're correctly informed by science. If my neighbor decides that 650ppm target is its ideal, he has the fundamental right to do so and to try to convince policymakers that he's correct. The same of another neighbor that would prefer 250ppm as the correct level. That is not relativism, that is democracy, as far as a policy goal which impacts everyday life is subjet to the citizens' evaluation in a democratic system. If Hansen et al consider in their 2008 paper that, concerning climate, the 350ppm target would be a good one, they’ve their scientific reasons. And this will be normally discussed by their pairs, as it is the case in climate sciences for decades, and all sciences for centuries. IPCC AR5 will integrate and evaluate this work among others; I've not the competence to judge if James Hansen is right or wrong, that is a scientific debate among specialists, and notably modelers. But when it comes to policy, I can observe that Hansen and co-authors are not specialists of energy, economy, health, sociology, agronomy, and many domains of expertise that are concerned by the energy supply and use in human societies (eg WG3 job). I suppose you’ll agree that we cannot choose a CO2 target for humanity on the sole basis of one paper concerning one aspect (climatic) of the consequences of such a target. All that is just a variation on the points 2 and 3 of the previous message. Beside this point, I was sarcastic in this deleted (and poorly inspired by irritation) sentence, but I'm opposed to the 'sacrosanctification' of the 450 ppm target for rational reasons I developed previously in the thread. And I profit to suggest fellow readers the interesting Andy Revkin recent article about COP Durban, with all its link, notably the William R. Moomaw and Mihaela Papa op-ed. #90 John : He not she. And he is not 'disciple' (horror) of Lomborg (but critical reader of some of his books).
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  44. @93, it is no more a democratic right to decide that 350 ppmv, or 450 ppmv or whatever target is ideal than it is a democratic right to decide that pi should equal 3. What is a limited democratic right is the decision to accept a certain level of harm. Having done so, it then is a matter of science as to what temperature increase (if any) will result in that level of harm, and what CO2 concentration will result in that temperature increase. As to what is an acceptable level of harm, here is the basic data: Note that the increase in temperature is from 1990 levels. From a < a href="">more detailed study we learn that:
    "The number of people living in water stressed countries, defined as those using more than 20% of their available resources, and is expected to increase substantially over the next decades irrespective of climate change. Particularly in the next few decades population and other pressures are likely to outweigh the effects of climate change, although some regions may be badly affected during this period. In the longer term, however, climate change becomes much more important. Exacerbating factors such as the link between land degradation, climate change and water availability are in general not yet accounted for in the global assessments. ... Over 2 C warming appears to involve a major threshold increase in risk. One study shows risk increasing for close to 600 million people at 1.5 C to 2.4-3.1 billion at around 2.5 C. This is driven by the water demand of mega-cities in India and China in their model. In this study the level of risk begins to saturate in the range of 3.1-3.5 billion additional persons at risk at 2.5-3 C warming [42, 48]."
    Now, you may think it is OK to democratically decide that it is better that 3 billion people go without adequate water than that they lose 3% of their income, but as the people being so democratic are not among those risking the loss of water, I don't think so. Hence a limited democratic right. The key point here, however, is that there are many scientific studies which show that the negative impacts of climate change rise sharply above 2 degrees C. You showed in your sarcastic sentence, and again in your comment above that you are unfamiliar with that literature. It you where not, your comment about a target only set as policy and by politicians would be actively deceptive. You critique Hansen and co-authors for not being economists, and it is true that they do have that virtue. An economist is, after all, a person who "knows the price of everything and the value of nothing", a fact shown by the repeated failure of the cost benefit analyses you are so fond of to include the costs of the loss of ecosystems. However, Hansen et al did not just pull a target out of their hat. Rather, they built on the work of Danny Harvey who showed that:
    "The allowable radiative forcing ratio depends on the probability of significant harm that is tolerated, and can be translated into allowable CO2 concentrations given some assumption concerning the future change in total non-CO2 GHG radiative forcing. If future non-CO2 GHG forcing is reduced to half of the present non-CO2 GHG forcing, then the allowable CO2 concentration is 290–430 ppmv for a 10% tolerance (depending on the chosen pdfs) and 300–500 ppmv for a 25% risk tolerance (assuming a pre-industrial CO2 concentration of 280 ppmv). For future non-CO2 GHG forcing frozen at the present value, and for a 10% risk threshold, the allowable CO2 concentration is 257–384 ppmv. The implications of these results are that (1) emissions of GHGs need to be reduced as quickly as possible, not in order to comply with the UNFCCC, but in order to minimize the extent and duration of non-compliance; (2) we do not have the luxury of trading off reductions in emissions of non-CO2 GHGs against smaller reductions in CO2 emissions, and (3) preparations should begin soon for the creation of negative CO2 emissions through the sequestration of biomass carbon."
    Here a 10% risk threshold represents (conservatively estimated) "... allowing for a risk of death to individuals that is 100- to 1000-fold greater than the one-in-one-million threshold adopted by the US EPA and NRC." A 25% risk, ie, the 450 ppmv threshold, represents a risk of death from global warming that may be as high as 1 in 400. Not adverse impacts, mind, but death. As indicated before, these studies consistently show adverse impacts across a range of measures rise sharply above 2 degrees C. Of course, there is a caveat here. The studies may be in error and the sharp rise in negative impacts may follow 3 degrees C, or 1 degree C. But taking a central estimate of a 2 degree C threshold, and assuming significant encroachment beyond that threshold is at least as bad as the upper range for 2 degrees, then pushing global temperatures to 2.5 oe 3 degrees C will only be 1 tenth as bad as the 1985 Ethiopian famine (death rate of 1 in 40). Of course, that 1 tenth as bad averaged across the entire globe, and will be much worse in particular places and at particular times. So, my "democratic" right is to decide between a 3% loss of my income, or an additional 1 in 400 chance of premature death for my grandchildren and all their contemporaries. Of course, the cost benefit analyses have this covered, and handle it very elegantly. They notice that most of those deaths will be in the third world, and that a third world life is not worth as much as a first world life - so the benefit of saving those future lives (another important factor in making the lives less important) does not weigh much against the cost of a loss of 3% of my income (which may mean I need to go a week without pizza). (Please note, Richard Tol is on record as defending exactly that analysis for his cost benefit analysis, which he is also on record as saying Lomborg distorted by using a different and prejudicial discount rate for when compared to other alternative for meeting the worlds needs. I'm not sure Tol is on record about Pizza, though.) Returning to Hansen, what he has argued is that the previous work on thresholds have used only the Charney sensitivity, and that a target set on that basis will result in the long term in significantly higher temperatures due to the long term feedbacks.
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  45. #94 Tom : I would have prefer a counter-argument on my 8 points in #91, but let's go. Your answer first brings us to another of my concern about Sphaerica’text. Why IPCC exists ? Because there are thousands of science papers each year, because there are dozens in independant climate models and enery-economy models, beacause we need a global assessment of the confidence of climate scientists about the robustness of their results. As it has been noted by SkS , ‘The IPCC was formed to report on a broad range of scientific enquiries into the climate, and our effects on it, and to summarise the science for laypeople. The science they summarise is published so it is simple to compare the primary science with the IPCC reports, and compare both to what actually took place.’ In this paper, SkS suggested : ‘Claims that the IPCC is alarmist are not supported by evidence, and there are clear indications that the opposite may be the case.’ I don’t know what means the ‘opposite’, but if it is suggested that we must not believe the IPCC reports because they are too ‘non-alarmist’ (the logical meaning of the sentence above), it would be particularly devastating in my point of view. IPCC has always been the target of deniers because the doubt on the quality on statements from IPCC reports would imply a disruption in the public trust in climate science conclusions, as it would be very easy to say ‘oh scientists disagree, all that is matter of debate, we’ll see later’. Previous point explains why I’ve problem with reference like Smith 2009 in PNAS. Why? Because it’s the job of the whole climate community (and not 17 of its members) to assess the reasons for concern from the whole literature (and not just part of this literature). For example, one of this reason for concern is the risk of extreme weather impacts. But there is a recent IPCC report dedicated to this specific question, SREX 2011 (quoted above), so we should refer primarily to such a report. At least, a reference to this report will have more weigh than a reference to a particular study in the thousand of studies among literature. Of course, you have the (democratic) right to select your references and to determine from them you own level of risk or dangerous change. It was my point, so feel free to refute or endorse it, but be coherent in your choice. For my part, I suggest the good choice would be to refer to IPCC. And I observe it is the typical denialist strategy to distrust IPCC and to cherry-pick the studies that minimize sensitivity, sea-level rise, icesheets melting, etc. Of course, from a skeptical point a view, a symmetric and opposite cherry-picking is of no value. That’s why the SREX reference is correct for our level of understanding about extreme events projections impacts, vulnerabilities, etc. And the future AR5 2013 will be the correct reference for broader conclusions about climate change. The same is true for Bill Hare 2005 paper : not only it is a one-man work, but it has been written before the AR4 2007 publication. So at least, you must refer to WG2 and WG3 2007 conclusion concerning the impact or mitigation, as I did above when criticizing some Sphaerica’s proposals. And the same for Danny Harvey 2007 Clim Change paper. More broadly, you’re speaking of the future deaths in the third world due to climate change. But nowhere you speak of present deaths in the third world due to non-climatic reasons and nowhere you critically assess the carbon consequences of policy choices for preventing these present deaths. As the long as this blindness to present problems is the rule in climate mitigation debates here, don’t expect any trust in the conclusions from such a one-sided approach. The 20 years CO2 rise is mainly due developing countries. So look at another publication from UN experts, the Millenium Development Goals report. What is said for example in the latest fact sheet about the first concern, Eradicate Extreme Poverty and Hunger ? : ‘Over a 25-year period, the poverty rate in East Asia fell from nearly 60 per cent to under 20 per cent. Poverty rates are expected to fall to around 5 per cent in China and 24 per cent in India by 2015 (…)The World Bank estimates that the effects of the economic crisis will push an additional 64 million people into extreme poverty in 2010, and that poverty rates will be slightly higher in 2015 and beyond than they would have been without the crisis, mostly in sub-Saharan Africa and Eastern and South-Eastern Asia. (…)Between 1990 and 2008, the proportion of underweight children under five declined from 31 per cent to 26 per cent in developing regions with particular success in Eastern Asia, notably China. Despite such improvements, progress is currently not fast enough to reach the MDG target, and particular focus is required in Southern Asia.’ So it easy to see how our economy and energy decisions will affect the quality of life in the world : million of children in China have benefit from the carbon-intensive policy of their government. A 3% of negative growth is not just about ‘pizza’, it is about damaging consequences for such million of people now, and billion from now to 2050. That is the reality we must all cope with : million of people now escape each year poverty, hunger, disease, illiteracy thanks to policy choices founded on carbon-intensive energy supply for the national infrastructures. The denialist attitude toward such a reality is no more sustainable as there is an exponential growth of emission from non-Annex B countries. As defender of an egalitarian agenda, the problem for me is not just the share of wealth, but the very first creation of the wealth we can share in the present and the future. Your involuntarily bad but so suggestive example of 1950 USA standard (point 8 above) showed how difficult it is to universalize what is perceived here in Western contries as a medium quality of life without the supply of huge amount of energy. This is not about pizza, this is about the present and next generation life. And this is about my main point of concern in the present discussion : if we are to prevent a too sharp CO2 rise, we must first understand the origin of the rise from a human needs perspective and we must assess our policy choices for their realism in that purpose of satisfying human needs. Not just draw scary but impotent scenarios for the second part of this century. Not just defend a 450ppm target as an unquestioned mantra. Let's say that Smith at al 2009 are correct and preclude the future IPCC AR 2013 conclusions, or that your 3 billion citizens water-disrupted estimate in 2070 or 2090 (for a 2,5-3K transient warming) is correct. In this eventuality, what must we do? Must we cut CO2 emissions at any cost, or must we cut these emissions in so far we can replace the carbon energy service they provide by another service of the same quality? Must we ultimately forbid or strictly limit the fossil supply even if we know that a non-fossil source cannot provide the same amount of energy for population needs? Is the urgent good choice a 450 ppm target or a progressive carbon tax or another strategy? What if tomorrow India or another giant simply leaves climate negotiations they perceive as a threat for their national development and the world sink in a selfish strategy of separate energy choices? How can we accelerate the deployment of RE energy now and not in 10 or 20 years? That are non trivial questions waiting for non-trivial answers. Hope you have the time to look at the Revkin's links, some of these deal with such new perspective of the climate mitigation strategy.
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  46., You continually present a false dichotomy. You require a choice of either "abandon fossil fuels 100% immediately" or "stay on fossil fuels until the entire world is safe from poverty." This fails because obviously there are solutions in between. The key point, however, is that any transition away from fossil fuels is going to take a lot of time so we have to start now. In Tom's words:
    It takes time to transition from a high carbon to a low or zero carbon economy. With the best will in the world it could not be done in less than twenty years, and ideally it would be phased in over 40 to 50 years (ie, through the natural cycle of replacement of obsolete power plants). Anything faster incurs significant increased costs.
    You are repetitively ignoring this reality by continually falsely representing the problem as an either/or choice between all or nothing. This is not the case.
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  47. @95, I am not interested in re-arguing the whole case with you. My intervention was simply to point out your biases and prejudices behind whose ramparts you where criticizing SkS as being insufficiently skeptical (a refrain you keep on returning to regardless of evidence). One key bastion of your fortress of bias was the claim that the 2 degree C (450 ppmv) guard rail was not based on science but on political discussions and decisions. I have comprehensively demolished that pretense above. You now retreat behind a further bastion, that we can ignore particular scientific discussions of the preferable target because it is not part of an IPCC summary, and hence not part of the consensus of climate science. However even this bastion is shadow rather than rock. If you wish to maintain the IPCC has provided no guidance on this issue, you need to explain the purpose of the updated reasons for concern and the discussion of mitigation strategies in Working Group 2. While doing so you would do well to note their opinion that:
    "...quantifying market-based damages associated with MOC changes is a difficult task, and current analyses should be interpreted as order-of-magnitude estimates, with none carrying high confidence. These preliminary analyses suggest that significant reductions in anthropogenic greenhouse gas emissions are economically efficient even if the damages associated with a MOC slowing or collapse are less than 1% of gross world product. However, model results are very dependent on assumptions about climate sensitivity, the damage functions for smooth and abrupt climate change and time discounting, and are thus designed primarily to demonstrate frameworks for analysis and order-of-magnitude outcomes rather than high-confidence quantitative projections."
    Fairly obviously a cost/benefit analysis that only demonstrates "orders of magnitude outcomes" has no inherent superiority to guard rail analyses, or analyses of stabilization targets. More crucial to this point,however, is the discussion in WG 3, in which they state:
    "[S]ignificant benefits result from constraining temperature change to not more than 1.6°C–2.6°C above pre-industrial levels. These benefits would include lowering (with different levels of confidence) the risk of: widespread deglaciation of the Greenland Ice Sheet; avoiding large-scale transformation of ecosystems and degradation of coral reefs; preventing terrestrial vegetation becoming a carbon source; constraining species extinction to between 10–40%; preserving many unique habitats (see IPCC, 2007b, Chapter 4, Table 4.1 and Figure 4.5) including much of the Arctic; reducing increases in flooding, drought, and fire; reducing water quality declines, and preventing global net declines in food production. Other benefits of this constraint, not shown in the Table 3.11, include reducing the risks of extreme weather events, and of at least partial deglaciation of the West Antarctic Ice Sheet (WAIS), see also IPCC, 2007b, Section 19.3.7. By comparison, for ‘best guess’ climate sensitivity, attaining these benefits becomes unlikely if emission reductions are postponed beyond the next 15 years to a time period between the next 15–55 years. Such postponement also results in increasing risks of a breakdown of the Meridional Overturning Circulation (IPCC, 2007b, Table 19.1)."
    The prospect of 10-40% of all species on Earth going extinct illustrates the severity of the risk imposed by AGW, a risk which increases with increasing temperatures. Of course, what you won't find in the IPCC reports is an explicit statement as to the appropriate temperature for a guard rail. That is because the IPCC reports are advise to policy makers, not policy making themselves. However, the clear advise of AR4 WG3 is that in the range of 1.6 to 2.6 degrees C, impacts are severe but potentially not catastrophic, where as beyond that all bets are of. In other words, the IPCC may indicate that there will be massive ecosystem collapse at temperature increases greater than 4 degrees C, with a minimum species loss of 35% (making global warming potentially the second or third largest ever mass extinction, and significantly worse than the K-T extinction event that destroyed the dinosaurs), but it is still open to policy makers to decide that life in a greater than K-T extinction event is an acceptable option. Of course, as citizens, they have no doubt that anybody who would take that option either is secure in the fact that they will not witness it, or are insane. Returning to the primary, and very simple point. You have indicated very forcibly that the 2 degree guard rail is simply a manufactured number for political convenience. I have demonstrated that, on the contrary it is a figure based on science, and science reported by the IPCC. The final decision was made by policy makers, but it was an informed decision. The question is, then, will you withdraw your objection to the 2 degree C guard rail as a reasonable basis of discussion? Or will you instead show by your intransigence that when the science is against you, you just ignore it?
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  48. Why on earth does SkS allow someone like "skept fr" to completely hijack a comment thread like this one and turn it into his/her personal blog site?
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  49. John Hartz - Personally, I'm a fan of less moderation, not more. While has put quite a lot of volume on this thread (and others), with an unfortunate tendency to use several hundred words where a few would suffice, I still consider this discussion worth having, and quite revealing/educational. * Skept.ft's objections have been shown to be a False Dichotomy between shutting down the world economy - and unchanged business as usual (BAU), claiming that any action leads directly to crushing the developing world. (S)he has simply ignored the middle ground, of replacing current power generation with renewables as quickly as possible. Even a 1 for 1 replacement of aging power plants would lead to a significant (if not, perhaps as speedy as we might hope) cut-back in CO2. But appears reluctant to even consider the middle range. * has also neglected the very real costs of continuing climate change, insisting that any limits on power generation are hugely more detrimental than mitigating climate change - again, a false dichotomy, and a strawman argument as well (as every plan I have seen includes ongoing increases in total power generation). This despite multiple studies indicating that mitigation will be far more cost effective than adaptation! * Finally, the ongoing focus on and criticism of any targets appears to be simple avoidance - 'No target is reasonable, so we shouldn't have any targets - take it easy, don't emphasis the risks, or you sound crazy', to paraphrase. This is simply a call for inaction. False dichotomies, strawmen, ignoring information on climate change impacts (It's not bad) - I see these as frequent 'skeptic' approaches that all should be familiar with.
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  50. #96 Sphaerica : "You continually present a false dichotomy. You require a choice of either "abandon fossil fuels 100% immediately" or "stay on fossil fuels until the entire world is safe from poverty." Wrong. I observe how humanity behave (in energy-climate question) and try to understand why. If you consider the nearly 10 PgC/y emission in 2010 as a problem, you cannot just treat this problem by its future consequences, but you're obliged to discuss its present causes. I don't understand why such a simple idea is problematic here. At least, I understand it is a bit OT, but your reactions are not on this ground. Sea after, answers to Tom are relevant for your point. #97 Tom Curtis : The question is, then, will you withdraw your objection to the 2 degree C guard rail as a reasonable basis of discussion? Or will you instead show by your intransigence that when the science is against you, you just ignore it? Of course 2 K is a reasonable basis of discussion! And even the 350ppm Hansen target is to be discussed. But a) a basis of discussion is not a dogma in policy affairs ; b) as you say, science advises policymakers but does not replace them (happily, unless you dream of kind of 'expert government' where the diversity of human values, beliefs, convictions and consequently policy goals is ignored) ; c) if a basis of discusion is not sustainable, it will be abandoned after having losen a precious time in the wrong direction, and you gave me zero argument for suggesting this basis is sustainable (whereas I put at several moment some orders of magnitude for local (eg Indian) or global energy needs, potentially non compatible with the basis of discussion) ; d) you have totally ignore my major points, notably my 8-points response about my supposed "caveats" in #91 and after my different questions in #95. Such avoidance is sad for me, I've done the best to answer your own arguments against my case ; e) I consider (without any amenity) neither you nor Sphaerica offered convincing argument when you're questioned about the dilemmas between present problems / future problems solutions. I suggest you must have a reflexion on that because it is an argumentative weakness when advocating climate mitigation strategy, and will be more and more in the coming years. #98 John Hartz : Don't know, if there are rules for the number of posts in a discussion, please indicate them to me and I'll respect this number. Anyway I suggest to stop here this endless debate, I'm really tired of it. (-snip-)
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    [DB] Argumentative snipped.  Let's all rein in all points not specifically germane to the topic of the OP of this thread.  This has descended to the point of "Yes it is" and "No it's not" and detracts from the dialogue on this thread.

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