When I wrote a brief squib last month about the new Holland et al. paper on sea ice decline, I made fun of myself for picking the worst-case scenario, suggesting a “a chance of an ice-free late summer arctic by as soon as 2040.” Apparently I was not alone. In her RealClimate post on the paper and its journalistic aftermath, Cecilia Bitz offers a nice explanation of the work and offers a similar observation to mine. The ice-free 2040 was the most extreme of a number of scenarios:
There is considerable uncertainty in future model projections, and Figs 2 and 4 illustrate why it would be better not to focus too much on the year 2040, which to our dismay was highly publicized.
In understanding why this happened, it is useful to look at the NCAR news relese:
The recent retreat of Arctic sea ice is likely to accelerate so rapidly that the Arctic Ocean could become nearly devoid of ice during summertime as early as 2040, according to new research published in the December 12 issue of Geophysical Research Letters.
In the news release, only the “ice-free in 2040” model run is discussed. It is the model run featured in the animation included with the news release. Is it any surprise that this is the scenario journalists chose to focus on, given that this is what the scientists, through their news release, told them was the most important?
Although, of course, it isn’t technically ice free by 2040 in even the most extreme scenario. Just not-much-ice.
John, the range of dates for near ice-free conditions for all seven runs is 2040 to 2050. NCAR’s “as early as 2040” doesn’t seem terribly out of line given this context. Other models (not used in the study) show different dates (Fig. 4), but most of those already track far off of the observations. Also, Cecilia notes that a straight-line extrapolation of the rate of ice loss for the last ten years reaches near ice-free conditions in 2060.
My simple point is that the authors’ dismay at the media’s emphasis on the 2040 date is misplaced if that’s what they chose to emphasize in their own press release. Bitz is the one who expressed dismay at the media’s emphasis on 2040, not me.
John, why do you assume the scientists wrote the press release?
I agree that their dismay does seem misplaced (or misdirected). Perhaps they didn’t even know what the press release said?
Mark – I don’t work on that side of the divide, but in my experience, the scientists are always involved in a collaborative, iterative process with their institutional public relations staff in developing the press release.
2040 is the only specific date in the abstract
too. Surely Mark isn’t suggesting that the PR staff wrote that too?
James – Good point. In fact, the abstract was all I had read when I did my cheeky post about this last month, not the press release.
Yeah, where I come from the scientists do get to write the abstract.
I submitted a comment (#39) on the Real climate article asking about this.
Of course it’s an *NCAR* press release. MH is resident there and presumably would have had some degree of input on its contents (if not an out-and-out signoff). CB, being at another institution, may not even have seen it in advance. Presumably she would have seen the abstract, and may not have been all that happy about it either.
Bear in mind that what we’re looking at here is a projection of a “charismatic” symptom of climate change that is sufficiently near-term that the authors probably will still be around by the time the projection is proven out (actually much sooner than 2040-50 since the sharp decline needed for the projection to be correct should be pretty obvious in another 20 years or so). Not every scientist is quite as willing as “Daredevil Jim” Hansen (or Kevin Trenberth, perhaps more to the point) to boldly strike out into such territory.
John, on my earlier point I wasn’t trying to blame you, but rather was pointing out that CB’s objection doesn’t quite make sense given the tight range of the model results. Would a press release referring to near ice-free conditions by 2050 *at the latest* have made her happier? Somehow I doubt it.
Bear in mind that what we’re looking at here is a projection of a “charismatic” symptom of climate change that is sufficiently near-term that the authors probably will still be around by the time the projection is proven out (actually much sooner than 2040-50 since the sharp decline needed for the projection to be correct should be pretty obvious in another 20 years or so).
Well, as far as I can see it’s taken about 8 months.