Climate Change — Some "Good News" For A Change?

This past week we've had some "good news" about future climate change based on an analysis published in the journal Science called Climate Sensitivity Estimated from Temperature Reconstructions of the Last Glacial Maximum by Andreas Schmittner, et. al. Here's the abstract, which I shall explain in layman's terms below.

Assessing impacts of future anthropogenic carbon emissions is currently impeded by uncertainties in our knowledge of equilibrium climate sensitivity to atmospheric carbon dioxide doubling. Previous studies suggest 3 K (°Centigrade) as best estimate, 2 to 4.5 K as the 66% probability range, and nonzero probabilities for much higher values, the latter implying a small but significant chance of high-impact climate changes that would be difficult to avoid. Here, combining extensive sea and land surface temperature reconstructions from the Last Glacial Maximum with climate model simulations, we estimate a lower median (2.3 K) and reduced uncertainty (1.7 to 2.6 K 66% probability). Assuming paleoclimatic constraints apply to the future as predicted by our model, these results imply lower probability of imminent extreme climatic change than previously thought.

Pre-industrial levels of CO₂ in the atmosphere were approximately 280 ppmv (parts-per-million-by-volume) over the last 10,000 years or so (the Holocene). The standard way for assessing the "sensitivity" of the climate to increased carbon emissions in post-industrial times is to model what might happen if there is a doubling to 560 ppmv. In other words, how much will surface temperatures increase in this case? The best estimate, even from the time the first models were developed in the 1970s, has always been 3°centigrade (C) within a 66% probability range of 2 to 4.5.

This new research suggests that the climate sensitivity is "only" 1.7 to 2.6 C with a 66% probability, and the best estimate within that range is 2.3°C.

CORVALLIS, Ore. – A new study suggests that the rate of global warming from doubling of atmospheric carbon dioxide may be less than the most dire estimates of some previous studies – and, in fact, may be less severe than projected by the Intergovernmental Panel on Climate Change report in 2007...

"Many previous climate sensitivity studies have looked at the past only from 1850 through today, and not fully integrated paleoclimate date, especially on a global scale," said Andreas Schmittner, an Oregon State University researcher and lead author on the Science article. "When you reconstruct sea and land surface temperatures from the peak of the last Ice Age 21,000 years ago – which is referred to as the Last Glacial Maximum – and compare it with climate model simulations of that period, you get a much different picture.

"If these paleoclimatic constraints apply to the future, as predicted by our model, the results imply less probability of extreme climatic change than previously thought," Schmittner added...

Some previous studies have claimed the impacts could be much more severe – as much as 10 degrees or higher with a doubling of CO2 – although these projections come with an acknowledged low probability. Studies based on data going back only to 1850 are affected by large uncertainties in the effects of dust and other small particles in the air that reflect sunlight and can influence clouds, known as "aerosol forcing," or by the absorption of heat by the oceans, the researchers say.

To lower the degree of uncertainty, Schmittner and his colleagues used a climate model with more data and found that there are constraints that preclude very high levels of climate sensitivity.

The researchers compiled land and ocean surface temperature reconstructions from the Last Glacial Maximum and created a global map of those temperatures. During this time, atmospheric CO2 was about a third less than before the Industrial Revolution, and levels of methane and nitrous oxide were much lower. Because much of the northern latitudes were covered in ice and snow, sea levels were lower, the climate was drier (less precipitation), and there was more dust in the air.

This is definitely "good news" if the paleoclimatic constraints found by Schmittner and his colleagues do indeed apply to the future. These results may even put the kabosh on hysterical prognostications emanating from the Jim Hansen/Bill McKibben wing of the environmental movement, although I doubt that they will. Needless to say, if these results hold up, an expected warming of 2.3°C is nothing to celebrate. That's still a huge shift in what amounts to no time at all on the geological timescale. The next most rapid warming we know of was the Paleocene-Eocene Thermal Maximum (PETM) which took place about 56 million years ago, and in which it took 20,000 years to get a 5-6°C rise in surface temperature.

The news, if true, is even better than generally thought because there's a snowball's chance in hell human burning of fossil fuels will culmimate in a doubling of atmospheric CO₂. In short, I don't think levels will reach 560 ppmv. I just don't see where all those fossil fuels are going to come from. Even if viable alternatives to fossil fuels miraculously appear, the possibility that global economic (GDP) growth will simply continue year-after-year in the 21st century seems very remote. There are all sorts of contraints on that growth, not just the availability of cheap energy.

Imagine it if you can: if atmospheric CO₂ were to grow by 3 ppmv per year, it would still take 56 years to get to 560 ppmv. That takes us to the year 2067. No way, Jose!

And that is the real reason the hysterical prognostications I mentioned above have always been laughable. Those making these dire predictions are employing the standard assumption used by economists, commonly referred to as Business-As-Usual (BAU). In short, these "radical" environmentalists assume that economic growth in the 21st century will (or could) mirror the growth of the 20th century. Not so "radical" after all. See what I mean?

Take this "good news" about future climate with a grain of salt. The path humankind is traveling still ends in disaster long before the year 2067. The Awful Truth is that this disaster is no longer impending. It has already begun. You'll see.

Bonus Video — here's some typical crapola from Bill McKibben (see my comments on this post).

 

Comments

[Ao]

Two questions:

- Do you mean 2067, not 2167?
- What hysterical prognostications has McKibben made? Even Hansen's have been pretty vague, not specific?

[Dave Cohen]

Of course it's 2067! -- corrected in the text. I shouldn't drink the night before I write. Or at least, I should have my coffee first.

Well, basically "hysterical prognostications" refers to 350.org, based on some not generally accepted research by Hansen and his people that says we've already made the Earth unlivable (over coming centuries) by exceeding 350 ppmv. It's another climate sensitivity argument. McKibben seized upon this research to promote his agenda, yet he must surely know that respected climate scientists (e.g. Gavin Schmidt of NASA GISS) do not accept it.

That's just plain dishonest.

McKibben has lately lambasted production of the tar sands, but the ultimate CO2 contributions from that development will likely pale in comparison to even the INCREASES in emissions we've seen from China over the last decade and will see in the near future. Like other climate scientists or activists, McKibben sees the tar sands as one giant pile of carbon, and further makes the unwarranted assumption that we will burn every pound of it. That assumption itself is based on bogus official "reserves" numbers published for Canada. All such estimates do not take into account the required inputs (energy, water) for tar sands exploitation, nor the net energy return for the harder-to-get bitumen (deep in the ground).

-- Dave

[RobM]

Turns out the short term "solution" to peak oil - abundant fracked natural gas - is worse for climate change than coal due to leaked methane. This recent Radio Ecoshock podcast is a must listen:

http://209.217.209.33/~esnet/downloads/ES_111123_Show_LoFi.mp3

[Gail]

Hm well, I have to part company with you here, Dave. From everything I have read, the IPCC and 350 are OVERLY optimistic - and that's not based on being able to continue to burn fossil fuels forever, it's based on all the amplifying feedbacks that are not easily predicted and so they are simply left out of the models. Of course Forbes and other denier publications are seizing on the purported "good news" aspect of this particular study, while ignoring this (http://scienceblog.com/49686/new-study-climate-sensitivity-to-co2-more-limited-than-extreme-projections/):

"Schmittner said continued unabated fossil fuel use could lead to similar warming of the sea surface as reconstruction shows happened between the Last Glacial Maximum and today.

'Hence, drastic changes over land can be expected,” he said. “However, our study implies that we still have time to prevent that from happening, IF WE MAKE A CONCERTED EFFORT TO CHANGE COURSE SOON.'" (emphasis added)

Aside from such distortions this study invites, their model like those used by IPCC ignores amplifying feedbacks like the albedo effect, and methane release, which are both well underway and unstoppable even if we stop burning fuels today, which we won't - and that's leading inexorably to the death of the forests, from pollution, which has never occurred before in the paleoclimate, it's wholly manufactured by human-created emissions. As the trees and other vegetation die, there goes a major carbon sink, which will lead to a higher rate of accumulation in the atmosphere, which leads to more warming. Not to mention the other major carbon sink, phytoplankton in the ocean, has been reduced by 40% in the last 50 years.

Hansen believes the Venus effect is a distinct possibility for Earth. He doesn't sound the least hysterical:
http://www.youtube.com/watch?v=ACHLayfA6_4&feature=youtu.be

There is a nuanced examination of methane and here: http://www.easterbrook.ca/steve/?p=2762

[Dave Cohen]

Re: "the Venus effect is a distinct possibility"

Yes, Hansen is full of shit. That didn't happen during the PETM, or the great Permian extinction 250 million years ago. Why would it happen now? Hysteria.

Re: amplifying effects (albedo effects, methane, release etc.), aka positive feedbacks

Well, the "good news" is that with a lower climate sensitivity, the odds have changed a bit in humankind's favor. Not that this will save us. Did you simply gloss over the part where I said --

"Needless to say, if these results hold up, an expected warming of 2.3°C is nothing to celebrate. That's still a huge shift in what amounts to no time at all on the geological timescale."

And of course, we'll never get to a doubling from burning fossil fuels alone, as I argued in the text. I wish people could get that through their heads.

-- Dave

[Dave Cohen]

And by the way, it's not my fault that climate deniers at Forbes are using the Schmittner, et. al results for their own evil purposes.

Gail, why do think I quote the phrase "good news"???

-- Dave

[Gail]

Dave, I'm sorry, I didn't mean to sound like I was accusing you of embracing "good news" or, god forbid, being somehow complicit with Forbes!! The reason Hansen says things are different now than the PETM or past "natural" shifts in climate from orbital changes or even volcanic or asteroid explosions, is the SPEED with which it is happening now, which is due to human activity, mostly burning fossil fuels. That unprecedented speed is what "could" push us into unstoppable heating, as well as mass extinctions, which are already a given.

RobM, that methane release from fracking is also important because it's not in the models for ozone, either, for which it is another precursor, so when the EPA regulates pollution, they are not accounting for it as I posted here last April, when Howarth's Cornell study came out:

http://witsendnj.blogspot.com/2011/04/anonymous-youre-no-sherlock-holmes.html

Thanks so much for posting the eco-shock radio interview - the blog had an interesting link to research by NASA scientists, something new for my collection! which stated:

"Shindell also thinks climate policy-makers need to pay much more attention to restricting short-lived pollutants, such as methane, carbon monoxide, volatile organic compounds (VOCs) and aerosols. This could create significant changes in the local and global climate quite quickly, he says, whereas the effects of efforts to reduce emissions of long-lived carbon dioxide will not be seen for many years. "The short-lived things are really powerful," he adds...

Mixed-up models

Methane, aerosols and other short-lived pollutants have a complicated chemical relationship, only some of which Shindell's models could capture. For example, methane leads to increased formation of ozone in the troposphere, which can reduce agricultural yields."

[Dave Cohen]

Re: the speed of the warming

Yes, that is a big concern, especially for species extinctions, but neither Hansen nor anyone else has been able to convincingly argue that some "tipping point" (a threshold) will be reached where the climate shifts into an irreversible state in which we are doomed. How could you? It's pure speculation. Hansen feeds people's fears.

The whole point is moot in any case because NOTHING is going to be done about global warming. I suggest that people get over it.

The narrower point is this: unwarranted hysteria is the polar opposite of climate denialism. Being based on emotional responses alone, neither position has merit.

This is just one of the many reasons I love our astonishing species, which dubbed itself Homo sapiens -- wise man ;-)

-- Dave

[Dave Cohen]

Recommended --

http://www.newscientist.com/article/dn21212-co2-may-not-warm-the-planet-as-much-as-thought.html?DCMP=OTC-rss&nsref=climate-change

Some details

http://www.skepticalscience.com/Schmittner-climate-sensitivity-goood-bad-ugly.html

There are concerns about the model used, and the LGM temperature reconstruction. These Schmittner, et.al. results are provisional, which I should have emphasized more than I did.

My remarks about the near impossibility that business-as-usual will continue for decades to come still stands.

-- Dave

[william mcdonald]

The models embraced by Mckibbon and others like him(including Obama, Salazar, Brown, the Governator, and the various bureaucracies)have been relied upon to provide the rationale for funding this new renewable energy rush being forced upon our desert wilderness areas of the southwest- giant land consuming projects being forced down our throats despite objections, all in the name of stopping climate change.

Now it turns out that maybe the whole thing was built upon a false foundation.

I have said many times on my blog that no firm or person with any business sense would build those projects, otherwise they would have been developed decades ago.

Nope this type of boondoggle could only happen due to well connected insiders picking the pockets of the long suffering tax payers.

A note to the treelovers out there who don't think this can effect their own favorite wilderness- this administration has already vowed to push new transmission lines through wilderness back east, it is only a matter of time.

Great post Dave!

It gives hope to those of us out here on the left coast who are against blading over the whole Mojave Desert, turns out things might not be so bad after all.

[Michael Stefan]

If you actually read the fine details, this study, if correct, is actually very BAD news for the future. Why? It assumes that the temperature change since the last Ice Age was actually much lower than currently assumed and as a result the climate is FAR more sensitive to temperature changes than thought. Joe Romm has a full writeup at Climate Progress:

http://thinkprogress.org/romm/2011/11/27/376197/media-flawed-study-climate-sensitivity/

Note also all of the record extreme weather events over the past few years - the effects from warmer temperatures alone are comparatively so insignificant that I wish people would stop focusing on how much warmer it will get, when floods, droughts and storms have a much bigger impact.

[disappointed fan]

Gail, thank you for your work here.

Sophomoric understanding and gut feelings are the domain of the GOP candidates, Dave.

furthermore,

Stop attacking McKibben, Hansen, and anyone else whose fight aligns with our own vectors. Our real enemies require every bit of our effort focused against them.

[Tenney Naumer]

I'm probably not stating this exactly correctly, but this new study used as a baseline a period of cold that had already been caused by a decreased level of CO2; this automatically subtracted some of the sensitivity.

The paper also does not consider what the effect of methane coming out of the permafrost and sub-sea permafrost in the Arctic will be.

Hansen brings up an important point in his book "Storms of My Grandchildren" (which unfortunately I do not have in front of me) -- the amount of methane stored now in the Arctic is far, far greater than it was the last time the methane "bomb" exploded up there.

Call McKibben whatever you want -- we are still permitted some limited forms of free speech, after all -- but note that he recognizes a problem and he is doing what he can, in his way, to try to solve it, instead of just spouting histrionics in a blog.