Arguments
Myth of the Mini Ice Age
Posted on 4 January 2012 by Rob Honeycutt
Peter Sinclair at Climate Denial Crock of the Week takes on the myth that sprang up again a few months ago suggesting that we were headed into a new mini ice age because of a new Maunder Minimum. This video features an interview Peter did at the American Geophysical Union (AGU) conference in San Francisco with Dan Lubin of the Scripps Institute of Oceanography.
Thanks once again to Peter.
Suggest that you embed a link to Sinclair's blog in the first sentence
I'm sorry if this is a little off-topic but I don't have any other way of communicating with Skeptical Science. I have been 'made aware' of this a paper which looks extremely suspicious to me and I wondered what your take on it is.
Natural Science, Vol.3 No.12, December 2011
Scrutinizing the atmospheric greenhouse effect and its climatic impact
by Gerhard Kramm, Ralph Dlugi
It seems to conclude that "energy-flux budgets for the Earth-atmosphere system do not provide tangible evidence that the atmospheric greenhouse effect does exist" - which strikes me as nonsense. Any more enlightened opinions than my own would be very welcome.
Thank you.
The crucial point here is that although Berger and Loutre 2002 found no example of a new glacial (ice age) under known orbital forcings with a CO2 concentration equal to preindustrial levels, with a CO2 concentration of 210 ppmv they found renewed glaciation. That is an intriguing number, for while CO2 levels may have stayed above that level in the absence of man, it is by no means certain that they would have. Indeed, given that CO2 levels would fall with falling sea surface temperatures, it is probably more likely than not that, absent the presence of man the Earth would now be entering its next glacial stage.
It should be noted that Berger and Loutre did not set out to, and do not claim to refute this possibility. Rather, they set out to refute belief among some paleoclimatologists in 1972 that "a slide into the next
glacial seemed imminent", ie, that given 1970's CO2 concentrations a new ice age was imminent but for industrial emissions.
Short answer is that the paper as a whole is pseudo-scientific nonsense.
A short comment for Tom Curtis @8: Note that the hypothesis that human activities influenced the rise of atmospheric CO2 after 7500 BP is highly controversial. For a rebuttal see Broecker and Stocker 2006
An alternative hypothesis for the rise in CO2 after 7500 BP is the regrowth of coral reefs following the end of the last ice age
Ridgwell et al., 2003. Growth of corals and other organisms that generate calcium carbonate shifts the acid-base balance of seawater which, in turn, releases CO2 from dissolved inorganic carbon.
Bill Ruddiman points out an even greater disanalogy. Whereas in the Holocene northern insolation peaked 11 thousand years ago, and have been declining since, in stage 11 they continued to rise strongly until the equivalent of 2,000 years ago (in the comparison) so that the standard comparison compares a NH peak in insolation to the current trough in order to prove that an Ice Age could not have commenced recently without the influence of humans.
Given the very large known deforestation by humans in the pre-industrial era, not the mention the artificial expansion of swamp lands in Asia due to rice cultivation, it is certain that pre-industrial humans had some effect on CO2 levels, and likely that they contributed at least half of the rise in CO2 over the last 7,000 years.
I will certainly concede that it is controversial whether they contributed more than that. However, that they contributed enough to prevent the onset of a new ice age remains possible on available evidence (SFAIK). Hence it is not a "myth" as claimed by skept.fr @6. Nor of course, is it certain, but I have never claimed otherwise.
next 100,000 years, the amplitude of insolation variations will be small, much smaller than during the Eemian. For example, at 65°N in June, insolation will vary by less than 25 Wm−2
over the next 25,000 years, compared with 110 Wm−2 between 125,000 and 115,000 years ago." The better analog for our present interglacial (from a solar orbital forcing comparison) is the MIS-11, which lasted longer than other glacial periods.
For the CO2 forcing at pre-industrial level, your point is not clear for me. For example, Lüthi et al 2008 showed some concentrations of 270-300 ppmv in past interglacials.
As you point out, Berger and Loutre provide an answer to the question as to whether the that 20 W/m^2 makes a difference. Their very clear answer is that it does make a difference if the atmospheric CO2 concentration is 300 ppmv. Indeed, they say:
(My emphasis)
As can be seen in the diagram, with a CO2 concentration of 210 ppmv (red dotted line), the simulation does indeed show us entering a new glacial, which we do not leave for over 100 thousand years:
(Also of interest is the red dashed line, showing 750 ppmv in which we loose all polar ice for very roughly 20 thousand years.)
So, the question of whether we would have entered an ice age but for the presence of humans resolves itself to the question, would CO2 concentrations have been currently below 220 ppmv (give or take) but for the presence of humans?
Well, we can examine this chart from Lüthi et al and find out some interesting things:
I want to note three things:
1) During the interglacials following terminations Tvi, Tvii, and Tviii, CO2 concentrations where in range of 220 to 240 ppmv, so an atmospheric concentration of 220 ppmv is possible in an interglacial;
2) Though atmospheric concentrations of CO2 as high as 300 ppmv have been found in previous interglacials, it has certainly not been for the entire interglacial, and in all previous interglacials, CO2 concentrations have followed temperatures; and
3) This is also true in the interglacial following termination Tv (stage 11), in which temperatures continued to rise after the end of the glacial, peaking in the middle of the glacial before falling away, with CO2 concentrations following the same pattern. That is indeed what we would have expected given the information we have about NH insolation during stage 11.
In stark contrast to stage 11, however, temperatures have not risen since the termination of the glaciation. Rather, they have fallen from the Holocence Climactic Optimum by between 1 and 2 degrees C. Despite this, CO2 levels have not fallen as we would have expected, but risen faster than they have in any other interglacial. It follows that stage 11 is not a counterexample to the claim that CO2 levels have risen throughout the Holocene due to human activity.
It is known that CO2 levels will rise or fall by about 12 ppmv per 1 degree C change in mean global temperature. That may be an underestimate, in that over the last two thousand years the ratio has been closer to 15 ppmv per degree C change in global temperature if recent reconstructions are to be believed. In any event, absent the presence of humanity, we would have expected CO2 levels to have fallen by 24 to 30 ppmv from the Holocene Climactic Optimum levels of 260 ppmv (assuming the most generally accepted temperature differential of 2 degrees C). That reduction in CO2 would have led to a further reduction in CO2, reducing CO2 levels by a approximately 10 ppmv, with a final current level in this scenario of 220 to 226 ppmv.
Given this, we cannot say with any certainty that we would not be entering an Ice Age where it not for human activity. As Boba10960 points out, neither can we say with any certainty that we would. If Hansen is right about Holocene Climactic Optimum temperatures, pre-industrial CO2 levels absent human activity would be in the 240 to 250 ppmv range, with a comfortable buffer against a new glaciation. Further, it is not certain that human activity is responsible for the additional CO2 entering the atmosphere, although the sharp contrast between this inter-glacial and previous inter-glacials is suggestive.
The point is "that GHGs prevent us from entering to the next glacial period" is unsettled science. It is not a myth, contrary to your claim at 6.
Last April Real Climate posted this review of the latest data on the influence of pre-industrial humans on climate. It says that there is still some discussion by experts, but most scientists find the explanation of human carbon dioxide starting about 7,000 (!!) years ago as fitting the data best. Interested readers should look at the linked article.
It is possible that the stable climate of the last 7,000 years was a fluke caused by human emissions of just the right amount of CO2.
Actually, Ridgwell does address the Holocene rise in CO2. His Figure 2a shows that the period of greatest regrowth of coral reefs was in the early Holocene. His Fig 2b shows that the modelled impact on atmospheric CO2 is consistent with the Holocene rise after 7000 BP. As stated in the first sentence of his conclusions:
"we find that the buildup of coral reefs and other forms of shallow water carbonate deposition, rather than changes occurring in the terrestrial biosphere is the more likely underlying cause of the observed rising trend in atmospheric CO2 during the late Holocene."
I'm not contending that humans had no role at all; only pointing out that a case can be made that regrowth of coral reefs and burial of other forms of calcium carbonate on continental shelves may have contributed significantly to the Holocene rise in CO2.
Michael Sweet @14, thanks also for the link.
On a related topic. How does the Skeptic Community see Robert B. Laughlin? He wrote a book titled: Powering The Future. It seems he takes some liberties, but he also seems well reasoned. He is a Nobel Prize winner in Physics. He said that Breeder Nuclear will provide 20,000 years of energy. He also siad that CO2 is not really a big deal. That Carbon is our friend. Is he another myth-sayer or just different outlook?
For example Coal at 5 cents a ton is by far the cheapest form of power. But outside China and India it is unlikely to increase much in usage.
Jimmy Carter thought liquified natural gas was going to power cars and poured billions of dollars into it. As we plainly know he was wrong. So much for the politicians deciding.
Somewhere in the middle we will find a power source. However we are going to need a lot less power. The consumption of consumer devices has dropped drastically in the last 20 years and that will continue. The next big step is dropping our heating and cooling energy needs.
Personally I think breeder reactors are unlikely. There is too much fear mongering against new nuclear reactors to allow such a thing to be built. If the fear is justified or not is not relevant. Political pressure has basically collapsed the industry.
I like thorium molten-salt technology, which was piloted and then dropped (although I hear China is pursuing development). It can't melt down (fuel cools & solidifies over the weekend), and it can't be used to make bombs, and generates much less high-level waste, plus thorium reserves are greater than U235 and U238. However, it needs more development.
But this is off topic.
On-topic: So THAT'S why I'm hearing "cold predictions" popping up - the bogus "it's sunspots" claim!
AGW has had to include CFCs as a cooling agent in order to explain the temperature decrease since 2000. If we are headed to a mini ice age it supports the theory of man made Global Warming without the use of CFCs on the mapping. Because CFCs are listed as a Global Warming chemical with 20 times the effectiveness of CO2 they are problematic as a cooling element.
So essentially you guys are writing off something that supports Global Warming theory more plausibly than CFCs... Who knows how long a Maunder Minimum is going to last which effectively means a Maunder Minimum could mean current Global Warming graphs estimates are low. Of course it also means the "Science isn't Solved" which may be why you are so quick to write it off.
That of course assumes a great deal of other things which I won't get into here. The devil is always in the assumptions right?
The devil is indeed in the assumptions, and you've made quite a few.
The radiative forcing due to current concentrations of CFCs is minimal compared to that of GHGs.
[I hate to pile on, but...]
1. Please provide citations to support your numerous outlandish assertions. Making stuff up (or arguing based on something you seem to recall having read somewhere on the Intertubes) is not science.
2. Are you really trying to pit what amounts to the magical, inexplicable theory of a supposed new Maunder Minimum against a theory that is well founded in current theory of physics and chemistry and is also well supported by all observations?
James, I assume that you have read somewhere about controversies over whether aerosol forcing is being underestimated (eg Hansen 2011) and you have understood aerosols (light-scattering particles - think Asian Brown Cloud) with CFCs (actually potent greenhouse gases). If you are actually interested in what the science is about, (which is neither "funny" nor comforting), then try looking at the SkepticalScience article here.
And please take some time to understand the basics before wading in with something from obviously borrowed from a site run by either the clueless and/or mendacious. Skeptical Science is a great place to learn those.
...so many possible misinterpretations to choose from...
Here is the basic physics of Global Warming. Global Warming is created by IR absorption and then thermal radiation of gasses. CO2, CFCs, SO2, etc. The energy comes into the earth as primarily visible light and radiates out as IR. Any gas that absorbs IR and reradiates it acts as a thermal blanket on the earth. More IR scatter equates more temperature sent back to the surface. This is the standard physics gas spectrometry is based on.
Any gas that absorbs IR and radiates it back is a GHG. GHG ratings by the IPCC are defined by how many frequencies of IR a gas absorbs. CFCs absorb a lot of IR because they have a lot of molecular connections. Sulfate absorbs IR. See link below.
Please read this on thermal absorption or google something
http://www.habmigern2003.info/future_trends/infrared_analyser/ndir/IR-Absorption-GB.html
Please read this on thermal radiation or google something
http://en.wikipedia.org/wiki/Thermal_radiation
As of 2007 the IPCC was using CFCs as a cooling factor to generate their graphs. This is *not* requiring of links because it is discussed on this site... It is also highly unlikely to be correct: see above for how Global Warming works.
The article you quote scaddenp quotes the same theory for IR absorption as a reflection.
If you look at this article on IR absorption you will see that sulfate absorbs in the IR spectrum. Thus it cannot cool it heats. This is the first response from google check a few others if you want.
http://www2.chemistry.msu.edu/faculty/reusch/VirtTxtJml/Spectrpy/InfraRed/infrared.htm
Oh and here is the IPCC talking about Sulfate as a greenhouse gas. (ie warming)
http://www.ipcc.ch/ipccreports/sres/regional/310.htm
For those who think Global Warming is caused by thermal conductivity. Ask yourself this. How many molecules are there in a vacuum (space). Or look up how a vacuum flask works (commonly known as a Thermos). The earth is a really good vacuum flask without the silver lining.
"As of 2007 the IPCC was using CFCs as a cooling factor to generate their graphs. This is *not* requiring of links because it is discussed on this site..."
From AR4:
"The Montreal Protocol on Substances that Deplete the Ozone Layer regulates many radiatively powerful greenhouse gases for the primary purpose of lowering stratospheric chlorine and bromine concentrations. These gases include the CFCs, HCFCs, chlorocarbons, bromocarbons and halons."
http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch2s2-3-4.html
"Oh and here is the IPCC talking about Sulfate as a greenhouse gas. (ie warming"
from the link:
"In transient simulations to 2050, the inclusion of aerosols based on IS92a (y,z) reduces the global mean radiative forcing..."
Their main net contribution is cooling, and this is well known by the IPCC.
A few things.
First... sulfates. They both absorb in the IR (a GHG property) and reflect visible light (a cooling property). The latter outweighs the former, by far, especially if the aerosols exist primarily near the equator where reflection (increased albedo) is key.
IPCC on Sulfate Aerosols
Specifically:
Second... when you make a statement like "As of 2007 the IPCC was using CFCs as a cooling factor to generate their graphs" please support that with a link. It is the sort of statement which leads to the confusion we are currently trying to untangle. Where have you read this? This is what I asked before, as did several others. What is your source of this assertion?
Please provide it. Without the source, we cannot figure out what you misunderstand (such as your misunderstanding about sulfates above).
"GHG ratings by the IPCC are defined by how many frequencies of IR a gas absorbs" By "ratings" you mean GWP? If so then only part of the story.
Sulphates might absorb IR but they are not gases (they are aerosols) and mostly act within climate as reflectors to incoming light.
Right at start of IPCC report, you have this graphic clearly stating CFC (halocarbons) as positive forcing agents not cooling. It would really help if you told us where you got this strange idea.
And now where is the evidence that any climate science thinks global warming is "caused by thermal conductivity"? This is a straw man.
I think James on the thermal conductivity point was actually making a point in favor of GHG theory, i.e. arguing against people that discount radiation as a major factor. This is only a guess, but I don't think he actually ascribes to that position himself (based on the rest of his writing).
The GWP values in the table linked here should be convincing enough:
CO2: 1.76 W/m^2; CFC-12 0.17 W/m^2; other halocarbons an order of magnitude less. These values are based on current (12/2011) atmospheric concentrations.
But if not, how about this graph?
So until we have our facts straight, let us dispense with the basic physics lectures, the instructions to Google this or that and the misquotes from IPCC documents -- all in favor of fostering a more civil discourse.
"Oh and here is the IPCC talking about Sulfate as a greenhouse gas. (ie warming) http://www.ipcc.ch/ipccreports/sres/regional/310.htm"
Read it more carefully. It shows that including sulphate (a negative forcing) in combination with the positive forcing of CO2 gives better match to actual data than just using CO2 alone. It references sections of 2nd IPCC WG1 report in support of that which you should do, though careful reading of the paragraph after the figure also makes that clear. The IPCC definitely does not think that sulphates are greenhouse "gases".
Does anyone have a link to actual experiments that show what rate Sulfates reflect light and what matter states they do so? Is this another numerically proven property like CFCs cooling in 2007? I am not saying that there isn't a cooling agent out there in fact I am willing to accept sun spots as that agent. Just that I'd like to see physical properties rather than simulated models for the reasons.
You can't prove the physical properties of an object by looking at a numerical model of them (Forcing numbers) The best example I can think of is Laminar flow. They do calculate the wing shape by numerical methods. They prove it works in a wind tunnel and testing the physical properties. They don't calculate a laminar flow wing. Say the math works and then do no physical testing. ie You can prove it with applied physics/engineering you can get an idea with math. There is also some particle physics where they used math to figure it out and observation to prove it.
CFCs where listed as a cooling agent in 2007. So when I said that was junk in 2008 I was right. Interestingly it now appears that the IPCC is using Sulfates as a replacement for CFCs as a cooling agent. I keep forgetting that I have to reread the "theories of Global Warming" because they keep changing. Pointing issues with 2007's theory of Global Warming is pointless I guess.
(-Snip-)
[DB] The topic of the OP of this thread is the Myth of the Mini Ice Age.
Please wrap up how these various points you are attempting to make are even tangential to the OP of this thread. As the others have already pointed out, the science does not support your assertions; you have yet to supply substantive cites for them that bear them out.
Off-topic snipped.
Also, you strongly suggest that a theory that goes through minor changes is a fraud. If so, it would be a ridiculous charge. Even if what you say about CFCs were true, it would not affect the fundamental theory of AGW: human-sourced atmospheric increases of CO2 will lead to warming. Any cooling effect you can think of will not challenge the basic theory. If the planet's temperature over the last century remained flat steady or declined, that would still not be evidence of a fundamental failure in the theory.
You should probably be more transparent in your purpose and targets, and of course you should provide evidence. Both of those actions will prevent you from coming off like someone who is incapable of being wrong or incorporating new evidence. Condescending? Yes, but all I have to go on is what you've written.
Not sure what you expect to have happened, but sulfate emissions (manmade pollution particles) from Europe and North America had begun to decline by about 1980 due to the clean air acts.
So...
"GHG ratings are calculated by the IPCC based on the IR frequencies that a molecule absorbs."
No. Repeating this without attribution yet again. Look up
GWP (Global Warming Potential) to find out actually done.
"Does anyone have a link to actual experiments that show what rate Sulfates reflect light and what matter states they do so?"
Look at the references in Penner as pointed out to you. You might also follow the IPCC references on how i
See IPCC AR4 WG1 for detailed discussion of aerosols - it answers your point.
As to direct methods, try here and follow cites. You
"CFCs where listed as a cooling agent in 2007. So when I said that was junk in 2008 I was right. Interestingly it now appears that the IPCC is using Sulfates as a replacement for CFCs as a cooling agent. "
This is tiresome. CFC were not listed as a cooling agent. You obviously continue to believe this nonsense is true, so for the last time, either put up where you got this weird idea from or take it back. IPCC lists aerosols as cooling agents in all the reports. You do understand that CFCs are not aerosols?
You have repeatedly been asked to support your claims and assertions with links. You have yet to do so.
Please support your assertions or retract them. Further comments along the same previous lines will be considered common trolling and treated accordingly.