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Dot Earth: Whiplash in the Greenhouse Print E-mail
Wednesday, 13 January 2010 05:08

January 13, 2010, 5:20 pm

Whiplash in the Greenhouse

There are a variety of debates under way over the merits or perils of focusing on particular climate (and sea level) findings, or  a particular season’s conditions, in discussing human-driven global warming.

Journalists sometimes do this, lured by the pull of the “ front-page thought” amid momentous, but complicated science. Campaigners pressing the  case for action (or inaction) on greenhouse gas emissions tend to be particularly keen to pick out findings that suit one of these agendas and ignore or attack those that don’t.

While a short-term benefit might be an attention-grabbing headline, one result, of course, can be  a sense of climate whiplash on the part of the public, and eventual disengagement or distrust as a result, if the finding proves to be an overstatement.

Over all, this process of fighting for attention seems to favor those advocating stasis. For one thing, they already have it far easier in what really amounts to a titanic battle over energy choices and policies. An object at rest (a public reliant on fossil fuels) tends to stay at rest. A little distrust, doubt, confusion or disengagement goes a long way toward moving a looming issue to a back burner, or entirely off the stove.

Here are a couple of instances illustrating related points.

On Monday, the BBC published an online opinion column by Richard Betts, a climate scientist at Britain’s Met Office, in which he described  the perils of climate overstatement and amplified on his thoughts on Dot Earth, discussing the mix of factors contributing to a big retreat in sea ice in the summer of 2007 as reason for care.

On his Climate Progress blog, Joe Romm on Tuesday chided Dr. Betts for  falling into the mindset of “anti-science disinformers” by focusing on Arctic ice extent, which has recovered somewhat, rather than focusing on the volume of ice, including its thickness.

Dr. Betts stressed that there was a definite declining trend in Arctic sea ice. His point was that both the big retreat in 2007 and the subsequent years’ slight expansion of ice were in fact distractions from the important trend that a host of Arctic scientists say is related to the warming climate. That didn’t stop Dr. Romm (who is a physicist but not a climate scientist) from trying to undercut Dr. Betts’ credibility.

Here’s my response to Dr. Romm, which was also posted as a comment on his site (a couple of typos are fixed):

A few points to note here, based on ongoing exchanges with about 15 cryosphere scientists, some of which took place  standing on the shifting floes around the North Pole (I vote for Joe to make a field trip):

1) There is still pretty wide agreement that the big melt of 2007 betrays as much about gaps in understanding and modeling skill as it does about the Arctic’s fate in a warming world. (Joe may recall my description of the much-touted “death spiral” as more a series of loop-the-loops — long-term trend clear, path murky.) Bottom line: the great ice loss of summer 2007 was substantially set up by the export of huge amounts of thick old ice many years earlier,  as described here:

“… The striking Arctic change was as much a result of ice moving as melting, many say. A new study, led by Son Nghiem at NASA’s Jet Propulsion Laboratory and appearing this week in Geophysical Research Letters, used satellites and buoys to show that winds since 2000 had pushed huge amounts of thick old ice out of the Arctic basin past Greenland. The thin floes that formed on the resulting open water melted quicker or could be shuffled together by winds and similarly expelled, the authors said.”

2) Joe’s focus on volume versus extent (or area) is a bit funky given the still-conflicting research on how much thin ice matters to the ability of the Arctic to avoid entering a new normal state of “no ice” summers. Note this excerpt from a piece of mine on various putative tipping points in the climate system: “For example, the idea that recent sharp retreat of summer sea ice around the North Pole has now taken on its own momentum has been challenged recently in papers by the earth scientists John S. Wettlaufer of Yale and Ian Eisenman of the California Institute of Technology. They contend that thin ice floes have the capacity to regrow quickly as summer ends, balancing out the melting that occurs as sunlight hits and heats dark open water.”

3) Finally, when the study of Beaufort Sea “rotten” ice came out, I queried my sea-ice posse (names provided on request) and they pointed to many issues with those conclusions. Hajo Eicken at the University of Alaska, Fairbanks, said satellite tracking has more problems when ice is, over all, thinner (this is just a tiny taste of the issues raised):

“I wonder whether over all the trend towards thinner younger ice may have resulted in a net underestimation rather than overestimation of the area of multiyear ice. What we observed at SHEBA (and see in Barrow on a regular basis) is that for thinner (< 2 m) multiyear ice and first-year ice, melt ponds can fill with seawater by the end of the melt season (due to higher permeabilities of such thinner, more porous ice), resulting in the overlaying of desalinated old ice by newly frozen saline ice in the fall and winter. As a consequence, a significant fraction of the multi-year ice has surface emissivity signatures of first-year ice.”

Yet more evidence of the hazards of putting too much emphasis on a particular paper, perhaps (in other words, supporting Dr. Betts’ point).

Here’s Dr. Romm’s reaction to my comment:

I would have said it is transparently obvious that ice volume is a better measure than ice area, if you want to understand long-term trend and the impact of human emissions — though it’s great to have both measures. Again, I’d love you to ask your leading cryosphere scientists whether the dramatic melting we’ve seen in recent years would have occurred absent the long-term warming trend. If you’re not refuting the volume analysis, then I can’t see how you can say focusing on ice volume is “a bit funky” — it’s clearly a more important measure of the system’s ability to recover, which is the central point of this post.

Of course, the Wettlaufer-Eisenman work mentioned above directly challenges the idea that thick ice is better able to recover than thin. And satellite and buoy monitoring make it patently clear that wind and currents can have a big influence on both ice thickness (as drifting old floes stack up and refreeze) and its fate — as floes drift out of the Arctic Ocean altogether. This animation, generated by Ignatius Rigor at the University of Washington, makes that point:

There’s one other relevant discussion under way, on sea level.

In a posting on one of the incredibly busy geo-engineering Google groups, Kenneth Caldeira, a climate researcher for the Carnegie Institution and Stanford University, criticized a British newspaper article — “Climate change experts clash over sea-rise ‘apocalypse’” — for overplaying the momentousness of one paper projecting a calamitous rise in seas by 2100 and then overplaying the level of dispute over the finding based on new work. Double whiplash, in a way.

Dr. Caldeira wrote:

I think this story in the Times is indicative of the press’s tendency to make a big story out of every individual paper, rather than reporting the picture that emerges out of the findings of a field of science over time.

He went on to discuss how the original paper’s sea-rise projection was, in his view, flawed, but also how the way it was described distracted from overall confidence about rising seas in a warming world. Then he wrapped his thoughts up this way:

“I think science journalism is in a terrible spot right now. Most scientific stories unfurl slowly, in a process that involves many different published papers, but journalists are tied to the news cycle and need to make a news event out of each story. So, to get space in the newspaper, they need to make it seem as if each published paper is a major event and the science is being whiplashed back and forth by each published study. (This is supported by the scientists who do each study and naturally feel the importance of their own study.) As a result, the public gets an exaggerated view of the volatility of scientific understanding. If the journalist[s] do not overemphasize the importance of individual studies, the stories will not get in the paper, and stories on the rising seas will be nowhere in the newspaper. Where is there a place for journalism that focuses on long-term trends?

And the answer, anyone?