The only thing we can be sure of about the future is that it will be absolutely fantastic. So if what I say now seems to you to be very reasonable, then I have failed completely. Only if what I tell you appears absolutely unbelievable, have we any chance of visualizing the future as it really will happen.

- Arthur C. Clarke (h/t Brin)

Saturday, February 28, 2009

The First Tipping Point



The first major threshhold of irreversible climate change seems to have been crossed. Things are probably never going back to "normal" in the Arctic. This may have large consequences.

The international Polar Year has issued a press release entitled

"Arctic sea ice will probably not recover":
As predicted by all IPCC models, Arctic sea ice will most likely disappear during summers in the near future. However, it seems like this is going to happen much sooner than models predicted, as pointed out by recent observations and data reanalysis undertaken during IPY and the Damocles Integrated Project.
Providing an object lesson of one of our main themes:


Yes, the models are imperfect.
No, that is not a reason to relax and forget the whole thing.
That is a reason to be more worried than the models indicate.


So does this matter? The IPY press release concludes that it may matter quite a lot:

The entire Arctic system is evolving to a new super interglacial stage seasonally ice free, and this will have profound consequences for all the elements of the Arctic cryosphere, marine and terrestrial ecosystems and human activities. Both the atmosphere and the ocean circulation and stratification (ventilation) will also be affected. This raises a critical set of issues, with many important implications potentially able to speed up melting of the Greenland ice sheet, accelerating the rise in sea levels and slowing down the world ocean conveyor belt (THC). That would also have a lot of consequences on the ocean carbon sink (Bates et al. 2006) and ocean acidification. Permafrost melting could also accelerate during rapid Arctic sea-ice loss due to an amplification of Arctic land warming 3.5 times greater than secular 21st century climate trends, as pointed out recently by Lawrence et al. (2008). This permafrost evolution would have important consequences and strong impacts on large carbon reservoirs and methane releases, either in the ocean and/or on land.

Are we having fun yet?

Update 3/14
: Similar news out of Copenhagen.

10 comments:

George said...

Who on earth is that strange man. Or "man". I'm having fun, but I'm not sure he's the answer.

Is he Al Gore? Al Gore is fat, and strange, you know.

Anonymous said...

Michael, a truly frightening way to start my quiet Sunday morning. And, the predictions of Arctic sea ice disappearing in the near future and all the consequential impacts that follow have been mentioned in numerous article and journals but not as conclusively as in the IPY report.

The impacts of an open Arctic Ocean are eventually going to coincide with other massive ecosystem and atmospheric changes such as expansion of the Tropical Zone and unabated deforestation in the Amazon Basin.

Amazon Basin deforestation leading to perpetual drought and warm surface air temperature over the Arctic region will have an effect upon the temperature and precipitation over the world’s grain basket in Western North America.

The US Pacific region is experiencing diminishing snow pack, earlier spring melt and low flow in Columbia and Colorado rivers and greatly diminished water impoundment behind dams that provide hydroelectric power and irrigation water to huge population and ag centers west of the Rockies.....and, who knows what else.

John L. McCormick

EliRabett said...

As one of the first to figure this out, hearing more evidence does not make Eli happy. Hysteresis is a bitch

Michael Tobis said...

George, the gentleman in question is known as Zippy the Pinhead, a sort of idiot savant who makes trenchant if somewhat disconnected observations about the modern condition on a daily basis but has not been known to do much about it.

Among Zippy's claims to fame is that we was the first to ask "are we having fun yet?". The commonly quoted question is usually uttered sardonically, but Zippy, as usual, simply wanted to know the truth.

Belette said...

It's not really clear to me what this press release adds.

It does say "Our main conclusions so far indicates that there is a very low probability that Arctic sea ice will ever recover" which sounds jolly exciting (though they don't tell you on what analysis that conclusion is based). Do you think that means that they would like to bet with me that in no future year will Arctic sea ice extent be greater than in 2008? Ah... thought not. So what does it mean?

Michael Tobis said...

I read it to say that in no future year will sea ice be greater than in, say, 1999, a bet I would take. That would amount to a recovery.

Perhaps it adds nothing new but it does constitute a sort of consensus statement, which means it's a stronger statement than one paper or another on the subject.

It would be worth setting up a real bet on the ice free Arctic, but we'd have to define terms precisely. On this matter, I'd be inclined to take your opinion seriously. What date would you proffer?

Belette said...

1999? I'd have to look up the figures. Obviously rather less attractive than 2008 :-)

Longer term, my bet with Romm that we won't be ice-free by 2020 is still open: http://scienceblogs.com/stoat/2007/12/betting_on_sea_ice_following_t.php but I suspect you won't find that attractive.

Michael Tobis said...

I am more curious about this: What year would be late enough for you to take the other side of the bet?

midwestman said...

Gee, no mention of the faulty sensor that was just discovered that showed we had way less ice than was actually there? I find it laughable that you, as a self proclaimed "scientist" would say (paraphrased from your blog) "No, the models are not perfect so we should worry even more and expect worse". Where's your scientific backup Mr. scientist? And no mention that global temperatures have not risen in the last 10 years even though our emmission of "greenhouse gases" have increased?

And let me ask one more question that most likely will never see the light of day on your blog: if there were at one time in the distant past Wooly Mammoths and trees in the Arctic that we now find under the ice, would that not mean that at one time, not under any influence of man, temperatures were warm enough there for them to thrive? Hmmm, man made global warming, er, I mean, climate change since I guess we're not warming anymore and you "scientists" need a different phrase.

Were you also one of the authors of the article of the Newsweek April 28, 1975 edition that said we were all going to die within ten years because of global cooling? Hmmmmm

Michael Tobis said...

Faulty sensor: not involved in the present discussion.

Models not perfect implies worry more: The costs are not symmetrical - they get worse very quickly as change increases - so the median expected outcome is optimistic compared to the mean expected cost.

No temperature rise in the last 10 years: tiresome cherry picking. Ten years is a chort time compared to the time scale of the problem and wobbles are expected.

Warm Arctic in past ages: pretty much irrelevant. We don't want it that warm now. Current rates of change are not normal and even unstressed systems would have difficulty adapting.

Newsweek 1975 is not a science journal.

All of these red herrings have been processed elsewhere at length.