Given the dramatic decline in summer ice coverage in the Arctic in recent years, some researchers have feared we are approaching the end of summer ice in the Arctic. But a new study, examining ancient driftwood found along the shores of Greenland, argues in Science that in fact it was much warmer 5000-8000 years ago. This means that summer ice in the Arctic may be able to survive human-caused global warming, presuming we are able to get a handle on emissions sometime this century.
From the Vancouver Sun:
While the researchers say they expect global warming will eventually make the Arctic sea ice disappear, they say the dire warnings about its imminent demise have been overstated.
"The bad news is that there is a clear connection between temperature and the amount of sea ice," says lead author Svend Funder, at the University of Copenhagen, adding there is "no doubt" continued global warming will reduce Arctic summer sea ice.
"The good news is that even with a reduction to less than 50 per cent of the current amount of sea ice, the ice will not reach a point of no return," says Funder, who has headed several treks to the inhospitable north coast of Greenland to get a better read on how the ice waxes and wanes.
Satellite records showing how the ice grows and retreats only go back to early 1979 — and suggest 2011 could see another record ice loss.
It's not great news. We are continuing to lose ice rapidly in the Arctic, as this graph from the National Snow and Ice Data Center illustrates:
11 thoughts on “Arctic ice not yet at point of no return, researchers say”
Did you read the paper? I seriously doubt that it holds out any hope for summer ice survival through the end of the century.
In terms of not despairing, well, an ice-free summer period is not by itself much more than a photogenic benchmark. If you want some despair, try the recent NSIDC permafrost paper (also largely misinterpreted by the media). The forthcoming Joye and Leifer results on the ESS methane may be cause for real despair, although they will need to answer the question of why there wasn’t a big release during the Eemian. (I can think of at least one plausible reason, which is that NH-only warming induced by Milankovitch cycles — the case in both the Eemain and the mid-Holocene discussed in the sea ice paper — may not heat up Arctic Ocean currents as much as an overall global warming. But we’ll see.)
Also, the NSIDC follow-up permafrost study, taking into account methane releases and full feedbacks, will probably not be good news.
I haven’t been able to get the paper for free yet, and I’m too much a free-lance writer to pay the $32, so no, I haven’t read the actual paper yet, just the abstract and various coverages. But numerous papers have reported the same basic idea, and Andy Revkin has had a thoughtful debate on the subject with Joe Romm, in which he discussed the science of Arctic ice coverage in convincing depth, based on years of reporting.
The big question for me is not when exactly the Arctic will be ice-free in the summer. That’s because I’m interested in the human response to these climate questions, as well as the science. The big question for me is: Will the persistence of sea ice in the Arctic mean that people will go on ignoring the changing climate completely?
It seems to me that people close their eyes to any change that is not apocalyptic, which pushes those of us who want to see the climate preserved, towards catastrophism. Seeing the apocalypse in every new study.
I would like to think, as I said in my post, that this study will ultimately help people to care about the fate of the planet, because I think (with Rachel Carson) that we connect on a profound level with the rhythms of eternity; the seasons, the rise and fall of the streams, the freezing and melting of the ice, and so on. I very much wish this.
But I don’t know it’s true.
Kit, mainly I was complaining about this passage:
“This means that summer ice in the Arctic may be able to survive human-caused global warming, presuming we are able to get a handle on emissions sometime this century.”
It seems to misinterpret this comment of Funder’s:
“The good news is that even with a reduction to less than 50 per cent of the current amount of sea ice, the ice will not reach a point of no return.”
What he means is that even at that reduced level, rather than melt out the rest of the way more or less on its own, the sea ice instead could survive *if*, as was the case in the mid-Holocene, warming proceeds no farther. The difficulty is that current CO2 levels are more than enough to push Arctic temps well beyond mid-Holocene levels. There’s no plausible emissions scenario that will save the late summer ice. Bear in mind that in the mid-Pliocene, CO2 in the 350-400 ppm range (which note we are now departing) was enough to eliminate all but a little winter ice.
As for the rest, while I share your feelings, the evidence would seem to be that humans are evolved to ignore or minimize the consequences of slow change. To the extent that the first instance of an ice-free summer period can be considered abrupt (arguable since the ice-free period will probably be quite short at first and will lengthen relatively slowly and unevenly), that fact that it will have been discussed to death before it happens I think will have served to inoculate people against assigning it the significance it deserves.
That significance, BTW, is not as a major event in itself but as a harbinger of much bigger things to come. Anyone who thinks we will respond appropriately needs to explain why we didn’t do so with regard to e.g. the historic first simultaneous opening of the Northern Sea Route and Northwest Passage.
Climate isn’t unique in this regard. This on the genesis and reception of the financial crisis is worth a read (and see this coda). It’s amazing how most people are able to avoid seeing such long-term detrimental trends clearly.
Re Revkin, don’t get me started. The most charitable interpretation seems to be that he’s allowed his desire for a comfortable future for himself and his family to color his view of the science.
Re catastrophes, the problem is that the list of possibles isn’t short. Lots of people have concluded that we’ll need one before anything close to adequate action on climate can begin. And if the consequences of the first catastrophe sharply curtail our ability to do so, well, c’est la vie.
Sorry, not just that passage, but your headline, which is entirely wrong for the reason I stated..
Again re Revkin (I can’t resist), notice that in the prior post he gets corrected by a couple of climate scientists. Note in particular that Marika Holland carefully limits her assessment of possible cooling from natural variability to a decade at most, which would be referring to the extreme case in an ensemble of runs, the rest of which do no such thing. But Andy casually conflates this conservative statement with a remark by another researcher some years back that such an effect could go on for several decades, glossing over what is in fact a big change in the science.
Then in comment 13, Andy asks Rigor how long he thinks significant summer-minimum ice will persist in the region north of Nares Strait and so provide a refugium for Arctic ecology. Well, based on my hypothesis (comes from reading most of the papers), I’ll predict that the answer will be some variant on not long. We’ll see.
The upshot here is that Andy formed a POV based on now out-of-date science and is having a hard time letting go.
Well, I hear your criticism of the headline. It’s true the study didn’t really talk about ice extent over the course of the century; it talked about the contribution of global warming to the melt, and the possibility of a pause in the melting.
It’s also true that more than one study as of late has taken a curious tack, talking about what might happen (to polar bears, for instance) if worldwide emissions moderate. Seems like a way of making a speech in disguise, almost.
Still, the news of this study, at least for me, is that the pause could last as or as a long as a decade, and possibly even reverse for a time. That’s what I was trying to get at with the headline, but maybe I should rewrite it…I’ll give some thought.
Scientists do seem to be getting much more speechy in that way.
OK, got the study and here’s the concluding paragraph:
“Climate models are the primary tools we have to quantify the contribution of internal variability to observed trends, and to assess if observed trends are outside the natural variability. The conclusions we draw are only as reliable as the underlying climate model processes. Only four ensemble members were needed to detect a forced September sea ice extent trend over the satellite period with CCSM4 (1979–2005), but going beyond detecting a forced trend to quantify the relative contributions of internal variability and anthropogenic forcing requires as many ensemble members as possible. The six ensemble members analyzed here are more than have been analyzed in previous studies, but we do not know if they are statistically representative. As large ensembles from credible models become available, the robustness of results presented here should be further evaluated.” (emphases added)
There are a number of things that a GCM can’t get right about sea ice, mainly because their resolution won’t let them. Beyond that, the model physics can’t be constructed correctly if the observations describing the physics don’t exist yet. This new paper is pertinent.
Gavin Schmidt said this a couple of days ago over at RC:
“This is mostly about a quantification of the size of internal variability. By looking at multiple runs with the same forcing and looking at the variability in short trends, you can make a statement about the range. The current trend is at the edge of what the NCAR runs show, and so it is conceivable that what we are seeing has been a weaker forced trend, combined with a (stochastic) increase to the trend because of internal variability. With that assumption, one can look at the other simulations and calculate the likelihood of the stochastic component going the opposite way and slowing down the observed trend. But these likelihoods rely on the NCAR model’s estimates of both the forced trend and the internal variability being correct. The former is less likely than the latter.”
IOW, we can’t be sure the Kay et al. paper is wrong, but it’s not very likely to be right.
Re the headline, it’s literally right if it’s taken to refer to ice in all seasons, but probably wrong if it refers to just summer ice (and in any case, as you say, the paper wasn’t addressing this issue). I say probably mainly because the whole summer season isn’t certain to be ice-free. If it were, there would be a bunch of missing ice in spring and autumn as well, and that seems a stretch absent some possible added feedback.
Solve Climate clarifies things with the lead author. She points to a problem with the press release.
Thanks for the link to the SolveClimate piece — really helped clear up the confusion. The relevant quote from one of the original study’s authors is worth posting on its own:
“I would really hate for someone to say, ‘If we had a 10-year increase in sea ice, that must mean greenhouse gases aren’t affecting the ice anymore,'” said Kay. “That’s not the case at all.”
Of course people have and continue to do exactly the same thing with global average temps!
Very strange sea ice behavior today, BTW. It could be some sort of artifact due to chance factors playing to a weak spot in the AMSR data, but perhaps not. The next day or two will tell, but if it’s real it’s an historic late season rapid loss episode. As Peter Wadhams said a few years ago, one day it will all melt away suddenly.
Of possibly even greater interest is SH weather just now. It looks as if there’s a polar outbreak of the same sort that the NH has experienced the last couple of winters. I’m not aware of one having occurred in the south before. Of course, as the winter polar vortices that hold in the cold air get squeezed hard and harder by the warming atmosphere, why should we expect them to remain stable? Eh, and what more could possibly go wrong?
BTW, I should mention that there’ve been several recent papers making the “not past point of no return” point, but the first of them was done by Connelley & Bracegirdle close to ten years ago. They took the simple approach of just removing all the Arctic sea ice from a model and seeing what happened. The ice recovered to its prior state quickly, IIRC in less than a decade. So case closed on that, although for some reason it hasn’t prevented others from announcing the same basic result as if it was new. (That’s William Connolley of RealClimate and Stoat blogging fame, BTW.)
One more thing: When Mark Serreze of NSIDC talks about a “death spiral,” he’s not referring to a persistent change of the sort that C&B disproved, but is simply saying that we’ll be seeing an ice-free summer period soon if warming doesn’t reverse (which it pretty much can’t on such a time frame). For some reason Revkin is unable to grok the distinction.