Arguments
Economic Growth and Climate Change Part 1 - Factors Influencing CO2 Emissions
Posted on 23 November 2011 by perseus
Environmentalists have long argued that we should adopt more sustainable models of living due to the limitations of natural resources and the environmental problems resulting from their exploitation. Probably the most serious environmental threat is climate change caused mostly by human activity in the form of greenhouse gases. We are currently on track for a warming of between 4 to 7.1 deg C over pre-industrial levels by 2100 according to Hadley centre projections. This level of temperature rise would threaten the stability of the global ecosphere as we know it.
The concentration of the most important anthropogenic greenhouse gas carbon dioxide (CO2) has been steadily increasing in the atmosphere since the 19th century, with the rate of emissions of this gas from human activities increasing by 45% between 1990 and 2010, and fossil fuel combustion being mainly responsible.
The so-called Kaya identity can be used to conveniently describe the key factors which determine fossil fuel CO2 emissions from an economic perspective
CO2 ≡ population x [energy/GDP] x [CO2 /energy] x [GDP/population]
Where energy refers to primary energy, energy/GDP the energy intensity, CO2/energy the carbon intensity, GDP/population the (economic) output per capita and GDP the gross national product. So this identity reduces to:
CO2 ≡ population x energy intensity x carbon intensity x output per capita
We shall briefly consider the potential for reductions in each one of these terms, although these can be interdependent.
Population
The InterAcademy Panel Statement on Population Growth, which was ratified by 58 member national academies in 1994, called the growth in human numbers "unprecedented", and stated that many environmental problems, such as rising levels of atmospheric carbon dioxide, global warming, and pollution, were aggravated by the population expansion.
Over most of human history, high birth rates have almost been balanced by death rates. However, as agriculture, sanitation and medicine improved, death rates, and particularily infant mortality reduced, this led to a more rapid population expansion. More recently, the global fertility rate (the number of children born per female) has fallen rapidly, halving between 1950-1955 and 2000-2005 to 2.65. Unfortunately, this reduction will take time to feed through to birth rates since fertility rates are also dependent on the proportion of women of child bearing age which is higher in a rising population. Therefore, global population is still expected to grow substantially before peaking. According to United Nation estimates it may have recently passed 7 billion and could reach 10.1 billion by 2100.
Whilst a reduction in fertility due to family planning and cultural changes have been partially successful in many developing countries, these changes have generally not been extended to Africa, and some Middle Eastern states, which still exhibit very high fertility rates. These countries may produce little fossil fuel based CO2 at present, but they can still contribute appreciably to other global warming pollutants such as black carbon and methane. Their populations may also aspire to the standards of the richest countries, potentially storing up severe environmental problems for the future.
A number of factors limit the efficacy of interventionist measures for controlling population growth. First of all sustained increases in longevity increases population. Secondly because the number of births per population tend to lag fertility changes, to halt population growth quickly it would be necessary to initially restrict fertility rates to well below two, which is a difficult policy to enforce. Even in authoritarian countries such as China, where this policy has been successfully used to control population, this can lead to social and economic problems due to the lack of young people to support the old in subsequent generations.
Energy Intensity [primary energy/GDP]
Energy intensity can be thought of as the efficiency we can turn primary energy into GDP. Methods of reducing energy intensity include improving thermodynamic or process efficiencies, such as increasing industrial plant and commercial building insulation properties. This shouldn’t be confused with simply using less energy, since some changes could reduce GDP by still more and therefore increase energy intensity.
The efficiency at which certain energy processes can be improved is at least at a basic level, limited by thermodynamic laws, however, changing the nature of economic activity is not subject to these limitations. For example, intellectual property would require very little energy whilst contributing to GDP.
Economic status strongly influences energy intensity. Generally countries with dominant, high value service economies such as Switzerland have a low energy intensity, whilst major petroleum economies such as Canada, Russia and Saudi Arabia have a high energy intensity. However, some developing countries such as Bangladesh have the lowest energy intensity of all since they are very efficient at translating energy into GDP.
Many developed economies have reduced their production based energy intensity as they introduced more efficient industry and moved towards a service economy importing products from abroad. However, when measured on a consumption basis this is usually higher
Some economists have proposed that increasing energy efficiency makes the use of energy relatively cheaper thereby fuelling economic growth, which could lead to increased use of energy and emissions of CO2. One version of this theory is sometimes better known as the Jevons' paradox. The degree of this rebound effect is uncertain but it can’t be ignored entirely, so efficiency improvements may have to be used in conjunction with taxes or emission caps to limit any significant effect.
Carbon Intensity [CO2/primary energy]
Large reductions in the carbon intensity of energy use can be made by switching to lower carbon fuels, such as from coal to natural gas, or from any fossil fuel to nuclear and renewable sources of energy such as wind and solar. Other greenhouse gases such as Nitrous Oxide and Methane, which can be translated to equivalent units of CO2 global warming potential, can also be reduced by changing agricultural processes.
Many countries tend to use the cheapest energy source available, which unfortunately for the two largest CO2 emitters, the USA and China is high carbon coal, and there appears to be substantial reserves of this fuel left. Fitting carbon capture and sequestering technology to coal power stations would reduce the carbon intensity of GDP by reducing carbon and increasing energy. Of course this might increase the output/capita term as well, reducing some of the benefit.
Replacing petroleum with some first generation biofuels will be more carbon intensive relative to fossil fuels due to the effects of deforestation for plantations, and emissions from nitrogen fertilisers. However, biofuels made from sugar cane, lignocellulosic feedstock and biogas from anaerobic digestion can reduce the carbon intensity of energy use relative to petroleum fuels.
Output per Capita [GDP per population]
The output of an economy is sometimes measured in terms of the Gross Domestic product (GDP) whilst output per capita is often considered an indicator of a country's standard of living.
The countries with the highest output per capita have historically been generally concentrated in three main economic blocs, the US, the European Union and Japan which between them have been responsible for the majority of global CO2 emissions. However, the expanding economies of China, Brazil and India have more recently become major emitters. This is due to their population size combined with a rapid increase in economic growth, although their output/capita has still a long way to grow before they reach the levels of fully developed economies. It is possible this will be repeated for the rest of the developing world later this century unless economic growth becomes limited by resources or environmental factors.
Economic growth dominates contemporary political and economic thinking, and this is reflected in our consumer oriented culture. Businesses attempt to expand, and individuals are encouraged to work longer to earn and consume more. Since world economies are so dependent upon fossil fuels for energy, fertilisers and a wide range of synthetic consumer products, increases in CO2 emissions have historically been correlated with economic growth.
In part 2 of this series we shall examine whether we can meet recommended CO2 targets by reducing the energy and carbon intensity alone as most economists and politicians desire, or whether we need to target economic growth as well.
It's not just the number of children that needs to be the focus. It's the age of first-time mothers and spacing bitrhs thereafter. In many countries, and in some areas within many more countries, this age is far too low. There would be a huge impact on population numbers worldwide if age of first child bearing were increased by 5 or even 10 years.
This is also related to longevity. The biggest population challenge is to reduce the number of years of generations overlapping alive at the same time. China is a classic example of restricting the number of children born without attending to a cultural preference for 4 generation families among significant parts of the population.
There's no need to say that 4 generations is bad. It's perfectly OK for grandpa to see a great-grandchild born. The big issue is how many years of life of the oldest and youngest generations overlap.
Increasing average age of first mothers .... by encouraging education and paid work (or at least work other than simple housework) .... can bring a population down quite quickly in areas where the average is currently below say 22, 24, 26.
Is the 2.3 based on the record fossil fuel consumption or is that going to hit next year's figures ?
I bet there are levels of material sufficiency that are lower than the developed world's current profligacy, but which could actually enrich us all in that most precious commodity - that of human happiness.
We do need to reduce carbon intensity, and fast. But reducing GDP, however taboo, is both necessary, and potentially hugely rewarding. Necessary, because even if we 'solve' the carbon intensity issue, our endless striving for economic growth is exhausting most of the world's ecological resources.
Hugely rewarding because, in a society where 30-50% of our labours is no longer required, just to fill the coffers of landowners; where the mass-consumer beast is finally dead and buried; where real needs are met, and false ones are no longer inflated -- in that society, we might all actually be able to achieve that fabled work/life/security balance.
(And no I don't mean 'going back to the Stone Age'!)
Climate change is just one part of the jig-saw, and it isn't even really the problem - it is just a symptom of the real problem.
Over-exploitation of resources, wildlife habitat fragmentation, climate change, pollution - these are all symptoms of there being too many people. I have seen it over and over again where a species undergoes exponential growth because of lack of predation, disease or competition. And in every single case such growth is simply unsustainable, and the population eventually crashes because of lack of resources and because their environment becomes virtually uninhabitable.
Humans are not different. And the result WILL be inevitable unless we change our ways - which we won't or can't.
You're right, and we must recall that, according to the last IEA WEO 2011 report (commented on SkS previous week) "over the next 25 years, 90% of the projected growth in global energy demand comes from non-OECD economies; China alone accounts for more than 30%, consolidating its position as the world’s largest energy consumer"
Main driver of world economic and energy growth is no more OECD, but the development of emerging countries in Asia, Africa and Americas.
I'll enjoy to read the 2nd part of your text.
The spectacular record rise in CO2 emissions in 2010 were really due to the recovery from the reduced emissions of 2009, although I should stress the trend over the last decade (averaging 2.4% per annum) iis seriously bad news. See graph down this link
Graph of carbon emissions
The news that atmospheric CO2 had risen 2.3ppm over the year 2010 was but conicidence. The 2010 record rise in emissions comprised 0.5 million tons of carbon above 2009 emission totals. That 0.5 million into the atmosphere would add roughly 0.1ppm to the CO2 level. As the WMO news release said, annual rises has been averaging 2ppm per annum. Again CO2 concentrations do wobble about but the trend is increasingly upwards. See graph down this link.
Graph of CO2 concentrations
(I will now have a try at posting them onto here as graphs but I'm not sure of their size & my record with web links is not good.)
[DB] The comment box field can accomodate image widths up to 500 pixels, if need be. Image posting advice is located here.
Not sure what you mean by that 'coincidence'; nor does data from MLO show 2010 was a record year for CO2 concentration increase:
year delta (ppm)
1998 2.93
1999 0.93
2000 1.62
2001 1.58
2002 2.53
2003 2.29
2004 1.56
2005 2.52
2006 1.76
2007 2.20
2008 1.62
2009 1.88
2010 2.42
Those figures suggest that global economic activity (both up and down) is a factor in the year-to-year rate of change.
Absolutely true. 2010 was not a record year for CO2 level increase. The coincidence was simply this above average 2.3ppm (or 2.42) increase coincided with record emissions.
I cannot agree with your final statement however. The wobbles you tabulate & shown in the lower graph are climatic wobbles not economic ones. They match the wobbles in ENSO pretty convincingly.
I'm not sure why this has to be an oversimplistic either-or. Clearly the two largest factors in CO2 level are going to be:
1) Economic activity which directly generates CO2
2) Ocean surface temperatures that directly impact the ability of the ocean to absorb (or even release) CO2
More activity generates more CO2 -- a lot more.
Higher temperatures retard the ability of the ocean to absorb CO2 -- a lot more.
Why must one completely displace the other?
I don't think one displaces the other. Surely they just have different impacts. The short-term wobbles from the climate are going to be there whatever the emissions. It's the emissions, driven by economics, that ramps up the CO2 over the longer term.
And to hone my graph-upliading skills, a wobble graph for you. (Hey, spot the volcanoes!)
Sphaerica is, of course, correct; the growth of atmospheric CO2 is modulated by both economic activity and the absorption by the oceans. But emissions are clearly driven by economics and global events:
data from CDIAC, graph source
Finer scale graphics reveal no coincidences in this behavior. The annual increment in atmospheric CO2 bumps up and down, but tracks emissions very consistently.
--source
I see a lot of major disconnects in your graph between MEI and CO2, which clearly points to MEI being only one factor, and not in any way the major short term factor in comparison to emissions. Clearly there is something missing, and changes in actual emissions are the obvious candidate.
You should amend your graph to clearly include a third line demonstrating actual human emissions each year.
My apologies but I'm at a loss what you mean by "a lot of major disconnects." This leads me to wonder what you are defining as "short-term".
The CO2 increase trace is characterised by a series of wobbles superimposed onto a rising trend of increasing slope. With the exception of the volcano years (63, 82 &91) the MEI matches the CO2 wobble for wobble with perhaps the exception of 2005-8. If the wobbles are the short-term features, surely ENSO represented by MEI is "the major short term factor."
That's where I'm coming from. Until I can grasp where you're coming from, thoughts of "a third line" (which will require the use of annual data on a month graph) would be premature.
What about 2002 on? What about amplitude, as well as an apparent "lag" in some cases but not others.
Your eyecrometer seems to be malfunctioning. You are seeing strong correlation and stopping your thought process dead because, in your mind, it's "close enough."
Again, why only include those two variables on your graph? Add emissions, then you can make your case more clearly and completely.
I'm not seeing the point of this wobblometry. Hansen and Sato's 2004 analysis was reproduced here by D. Kelly O'Day.
If you are suggesting there's some sort of causal relationship between MEI and deltaCO2, what is it and why does it work? And why would that be important, as it is little more than an oscillation on a rising trend?
You're asking a bit too much here. The lag (always present) is variable in length and perhaps could be due to the season the El Nino/La Nina occur in. Also the ampitude. Or whatever. That use of an index like MEI comes so close to the CO2 rises with only a starightforward linear re-scaling I fine pretty impressive. And getting a better fit would require a step into the modelling arena, a major piece of work.
The “2002 on” section – I wonder that if the next El Nino sees CO2 rises passing well above 3ppm pa, those wobbles wouldn't then look so odd.
Your requested 'third line' will require a mix of annual data & monthly data so this is a little more of a task than something done over a cup of tea. And I do wonder what would be gained by plotting CO2 emissions as a separate line. If this does gain a place on my to-do list, I would see more to be gained by subtracting the emissions increase to leave the wobble without the trend.
(Of course, it doesn't have to be me that creates the graph when the data is available to all.)
MEI data
monthly CO2 data
CO2 emissions – FF & cement
CO2 emissions – land use
Hansen & Sato 2004 see the wobbly soak-up rate as important enough to spend one page of a six page paper discussing it. It is as you say but an oscillation on a rising trend but big enough to reduce annual increases by 70% in consecutive years. The causal link – high MEI will restrict ocean absorption of CO2, low MEI will assist it setting the CO2 wobble in motion.
(One comment – I was surprised to see the 55% figure for CO2 remaining in the atmosphere on your second graph @14. 40% is a more usual number. I linked back to the graph's origin & CO2 data source & saw two problems. The USEIA CO2 data is a bit low but more worrying, the emissions for land use change appear not to be included in the analysis.)
The links have picked up extranious characters.
They are in order:-
http://www.esrl.noaa.gov/psd/enso/mei/table.html
http://cdiac.ornl.gov/trends/emis/meth_reg.html
You are aware that ENSO affects atmospheric CO2 because of the extra rain that falls over land during La Nina stimulates vigorous plant growth, and cooling of sea surface temperatures?
Conversely El Nino warms the sea surface (particularly the equatorial Pacific) which increases CO2 outgassing from the ocean, and the marked drying of the tropical basins diminishes plant growth, and therefore they too give up CO2 to the atmosphere.
Volcanic eruptions tend to ramp up CO2 uptake by land-based plants because the diffraction of sunlight enables light to better penetrate the forest canopy.
If none of this has anything to do with what you guys are debating, please disregard.
Not so much. Here's H&S' main point on that question:
Year-to-year fluctuations of atmospheric CO2 growth must reflect fluctuations of the land and ocean sinks for CO2 and the biomass-burning source.
Most of the rest is about other GHGs.
"40% is a more usual number"
Is it? Again H & S:
Fig. 5A shows the CO2‘‘airborne fraction,’’ the ratio of the annual increase in atmospheric CO2 to annual fossil fuel CO2 emissions. Despite large year-to-year fluctuations, the airborne fraction has been remarkably constant at ~60% of emissions during the post World War II period
Nor is there any mention of ENSO or either NinX in this paper. Again, I'm not seeing the point of this wobblometry.
Adelady. Yes there are other factors affecting population growth. In India the low proportion of females to males born is yet another, which will of course reduce population growth. However, it is notable that all of the methods if overdone could lead to social or economic instability in later years.
I fear that in placing all our eggs in the same environmental technology basket we risk the same over optimism as when we predicted 'cheap' nuclear energy, routine space flight and artificial intelligence. I'm not saying these won't happen eventually but we need to combat AGW now to avoid tipping points, and our best chance is to tackle it on several fronts.
Good points in posts 4 and 5. However, austerity tends to be relative not absolute. We already have more than enough in the developed world. It is hardly unreasonable to expect people to avoid waste and excess and a great deal of our GDP is just that, it adds little of true value but creates environmental problems. Even the so called green technologies can generate pollution especially if it is done on the cheap:
pollution casts shadow over Chinese solar
rare earth metals technology boom
Yes carbon is not the only issue, we live on a finite earth with limited resources and sinks, perhaps we also have a responsibility to other species as well and the more we consume the greater stress we place on these habitats.
So instead of sitting back and waiting for better health and increasing prosperity to advance the causes of lower birth rates and improving women's status, you do the status and education first. And this always leads to better health for children and the community at large. Hey presto. Fewer children born further apart and all much healthier than before.
There's at least one program working very well in Africa where the focus is on education for girls and later marriage for both men and women. One surprising outcome of this, then not so surprising when you think about it again, is that the boys are tremendously relieved that they don't have to take on the burdens of providing for a family as soon as they leave school.
Everyone wins.
Again, I agree with you. We all remember nuclear energy "too cheap to meter" and other unrealistic optimist projections, very usual in energy litterature since the XIXth century. Energy transitions are slower than we like to imagine, and that's true since the first wood to coal transition of industrial period. We can accelerate the pace by political will, but there are heavy constraints from the installed energy infrastructure and their socio-economic implications. Furthermore, electricity is just a small part of the problem because fossil fuel are also used for transport and heat, and they are uneasy to substitute in metallurgy, production of cement, plastic, glass, etc. Of course, scientists work on alternative solutions in all process, but the deal for a 450 ppm scenario is not just to replace a coal plant by a wind or solar farm.
In last resort, such considerations also depend on the total energy production we aim, which itself depends on material quality of life and growth targets (your paper!). Humanity consume now approx. 500 EJ/year so, if you wish it consumes 250 EJ/year in 2050, it will be far more easy to achieve a zero carbon economy. But if you target 750 EJ/year at the same year, no hope with current technologies – we are not even sure there would be enough cheap fossil reserves to reach and sustain this level!
Concerning "austerity" (we will probably discuss it with the 2nd part of the paper), the problem seems to me on first approach : who decide of the 'fair' level of individual, national or global austerity ? As we can observe in climate negociations rounds, it's as uneasy to convince emerging countries that they are already sufficiently "rich" as it is to convince rich populations policymakers that they must downsize their GDP for climatic reasons. And as we observe in everyday life, few people diminish spontaneously each year their carbon or energy footprint so as to divide it by 4 in 30 years.
I didn't ask for a line showing CO2 levels, I asked for the change in emissions (you know, the other factor that contributes to the wobble in CO2 levels).
#28, #29 : I don't clearly understand the issue... there are annual variations of CO2 atm. concentrations due to variability of climate (efficiency of biological-physical pump) and of economic activity (for example 2008-2009 recession), but the long term trend is due to economic activity, and it is correlated to the multidecadal growth of our fossil-based economy.
If you are going to show CO2 atmospheric variation then you must also show CO2 emissions variation, and scaled proportionately to allow for a fair visual comparison. Compare apples and apples, not apples to miniaturized oranges rolling up a ramp.
And what exactly is the point of "40% emissions subtracted?" That seems like a rather arbitrary and unnecessary adjustment.
And why is this graph suddenly so very, very different from the one posted in comment 12? You have some explaining to do.
The blue line is the annual CO2 emissions scaled by 40% and reported in terms of change in ppmv to give it the same unit as the mauna loa data.
As such, the two lines @28 break the annual CO2 increase into two components - a variation due to human emissions and that due to natural fluctuations. In order to do this, it is necessary that the human emissions be scaled to account for the average absorption of the emissions by the oceans and biosphere. That the 40% scaling is approximately correct is shown by the fact that the black line @28 looks like it has been detrended. As such MA Rodger's graph shows much the same information as Hansen and Sato's graph @17 except that MA Rodger shows the MEI, and also includes emissions from cement manufacture and land use change.
I believe Hansen and Sato's presentation to be better. If MA Rodger was to continue graphing this data I would suggest he adopt the Hansen and Sato presentation, except showing the linear trend of the airborne fraction instead of the seven year mean. He could then show the detrended airborne fraction (mauna loa data) against the MEI, and idealy the VEI (and both together). Another interesting plot would be against the detrended global mean sea surface temperature.
So perhaps if I present a calculation of the maximum size of the blue wobbles that we should expect to see @28, that will settle this matter one way or the other (being off topic and all). If my calculation contains error, then I'm a blithering idiot and apologise. (I've no problem with that, but I'm not that often wrong.)
(1)When shed of seasonal changes, the CO2 level MLO data exhibits a wobble and a rising trend.
(2) The wobble's size is up to 2ppm peak to peak (as seen in graphs @12 (use left hand scale) & table @9). Less unusual in size, the 2006/10 wobble is some 0.75ppm peak-to-peak.
(3) I contend that these wobbles are overwhelmingly natural. Three folk on this thread assert/suggest that I am wrong.
(4) The largest variation in human emissions (twice the size of any other) is the change from 2009 to 2010 (as in red line in upper graph @8). This totals +512 - -122 = 634 million tons of carbon (or 0.634GtC).
(5) Not all this carbon will remain in the atmosphere. The graph @28 uses 40% of all CO2. As land emissions are assumed for 2006-10 and treated as flat, I shall be very generous and use 60% in this calculation (so the wobble we are calculating here should be 50% bigger than the @28 graph). Thus Atmospheric CO2 wobble due to human emissions would be 0.634 x 0.6 = 0.3804 GtC.
(6) It requires 2.13 GtC to raise atmospheric CO2 by 1ppm. So the 2009/10 wobble will be 0.3804 / 2.13 = 0.179ppm.
(7) In comparison with the total wobble maximum p-t-p in graph @12, the maximum peak to peak wobble from emissions is thus 0.179ppm / 2ppm = 9%. The 2009/10 emissions wobble occurs during a total wobble of about 0.75ppm p-t-p, so for this one instance on the 50 year record, the human emission wobble almost manages a quarter of the total and would be less than a sixth if 40% was used in (5). The graph @28 does use this 40% & the graphed wobble is an expected 0.11ppm p-t-p. The impact on the residial wobble in the graph @28 is thus hard to spot.
I do hope we can reach a resolution here in this off-topic point. (And I will leave it there without direct reply to @33 or @34) As ever, I am happy to own up to being a blithering idiot if I am in error.
Yes. My simple complaint (without directly stating it) is that the atmospheric CO2 line appears to be detrended while the CO2 emissions line is not, and then they are presented with vastly different scales, masking the wobble in one while exaggerating it in the other.
35, MA Rodger,
Picking one year is pointless. That's not how one does statistics. Honestly, your point isn't worth arguing, but you have had several posts with which to prove it and all I see evidence of there is an effort to sell your point rather than to clearly present the data. I'm not saying that you're wrong or right, I'm saying that you've used very unclear and ill-chosen graphics and numbers, with what appear to be rather arbitrary choices that wind up masking the relative factors, and so you have failed to prove your point.
By this point, however, I'm simply bored with the issue. It's not worth this much discussion.
1) The annual change in total emissions from year to year in GTC (GigatonnesCarbon);
2) The annual change in atmospheric CO2 from year to year in GTC; and
3) The annual change in atmospheric CO2 minus the change in total emissions in GTC.
If you would do so, the argument between you and Sphaerica should be settled. I believe that such a graph will show conclusively that your interpretation is correct. I am unsure whether Sphaerica is misunderstanding you as saying natural variation dominates the long term trend (which is of course false), or whether he believes the short term variation in human CO2 production to be large.
If the later, it would be because he is unaware just how little major economic shocks actually effect the actual productive capacity (and production) of the global economic system. Those shocks are not brought about by failings in fundamental economic capacity, but by failings in the superstructure of capitalism. As a result, unless they are left to fester (as in the Great Depression), they have little overall impact on actual production. Even the great depression reduced CO2 annual emissions by only around 15% (and hence involved only a 15% reduction in productive capacity). In terms of lost productive capacity, the Global Financial Crisis which still included massive economic growth in India and China, was barely a wimper. (This is not to downplay the real suffering it has caused for many people, but that suffering is not due to a loss of economic capacity, but due only to a loss of willingness to deploy that economic capacity by the holders of capital.)
This graph (and others on more suitable scales) dispute that.
"Even the great depression reduced CO2 annual emissions by only around
15%26%"That is not a little effect; it is plainly visible on the CO2 emissions curve, as are the Arab oil embargoes, the post-Gulf War recession and even the GWB recession of 2001. Zooming in further, changes in US emissions very visibly drop during these economic stress points:
tamino addressed this entire question here.
He models the CO2 growth curve remarkably well from a combination of the linear trend and MEI:
Engelbeen also produced this graph, demonstrating a remarkably consistent slope (percentage of cumulative emissions remaining in the atmosphere) of 0.53:
Oh so, we can go back to the real topic of perseus post: if (fossil-based) economic growth is the major driver of CO2 emissions' upward trend since 1850, can we break the correlation in the future (keep the growth up with CO2 down) and if we can't, should we break the growth itself? (But these core questions will probably be treated in the part 2, so may be it is better to wait for the next perseus post? I don't know when (s)he plans to post).
I believe that this graph shows conclusively that natural variation is the major component in changes from year to year in atmospheric CO2 concentration.
To avoid misrepresentation it should be noted that the graph does not show the annual emissions of CO2, but the change in the emissions from one year to the next. Had it shown the annual emissions, they would clearly have been much larger than the year to year fluctuations. Indeed, the first graph in post 40 shows exactly that. Therefore, and without any doubt, anthropogenic emissions are responsible for the long term trend in the graph of CO2 concentration.
Last week I made this very point to a group whose arguments on population were degenerating along racist lines. I was the only male arguing that education and womens rights were the key to population control, a surreal experience!
This was broadly encompassed under the term 'family planning and cultural changes' in the text. Perhaps it would have been best to mention female education and rights more explicitly!
Sir David Attenborough recently covered these issues in the documentary 'How Many People can Live on Planet Earth'
http://topdocumentaryfilms.com/how-many-people-can-live-on-planet-earth/