Warming Is Unequivocal
by Bill Chameides | February 23rd, 2010
posted by Erica Rowell (Editor)
Is the Wall Street Journal making like an ostrich and sticking its head in melting permafrost?
If you haven’t already, check out the editorial page from yesterday’s Wall Street Journal. On it you’ll find a spirited, one might say angry piece by L. Gordon Crovitz entitled “Climate Change and Open Science: In the Internet age, transparency is the foundation of trust.” The piece riffs off a BBC interview with Phil Jones, the embattled director of the Climate Research Unit at the University of East Anglia, to reach its inevitable conclusion that “equivocation has replaced ‘unequivocal’” in the climate science world.
That word unequivocal in this context carries symbolic meaning, having appeared in the latest assessment of the Intergovernmental Panel on Climate Change: “warming of the climate system is unequivocal.”
The word was included in the report after much discussion and debate and, as I understand it, was retained over the objections of some politicians at the insistence of the scientists. Now the climate skeptics, including apparently the Wall Street Journal’s editorial board, would like to use the climategate incident to take the ‘un’ out of unequivocal.
Is the WSJ Editorial Page Getting Yellower?
As noted in yesterday’s TheGreenGrok, the media coverage of climategate has not been exemplary of journalism at its best. Now outlets like the WSJ are using the occasion of the Jones interview to pile on — using quotations taken out of context to press their attack on climate scientists. RealClimate has a nice piece on how the Daily Mail inaccurately spun the Jones interview to undermine the science.
The WSJ’s editorial follows a similar path. Here is one example.
The piece states: “Phil Jones … acknowledged to the BBC that there hasn’t been statistically significant warming since 1995.” OK, that is what he said, sort of. Why sort of? Because the WSJ conveniently neglected to include the context.
Actually, Jones said that there was a warming trend in global temperatures since 1995 — at a rate of 0.12 degrees Centigrade per decade (or 0.2 degrees Fahrenheit per decade). But because of the short time period, the rate was not quite statistically significant at the 95 percent confidence level. It was “quite close to the confidence level” but not quite there.
Newspaper Decontextualizes Quotes, Misleading Readers
Simply put, a 95 percent confidence level means that there is a 95 percent probability that the actual temperature trend was positive and a five percent probability it was not. The 95 percent confidence interval is referred to by statisticians as “2-sigma” because it covers two standard deviations from the mean.
Scientists often choose the 2-sigma or 95 percent confidence level, instead of the 1-sigma or 68 percent confidence level, to be conservative in their conclusions. Note: climate scientists are being conservative in their pronouncements about global warming, not the other way around.
Here’s the point, Mr. Crovitz: saying that there was no statistically significant trend is not the same as saying the temperature trend between 1995 and today was positive but not significant at the 95 percent confidence level — in fact it was statistically significant at a slightly lower confidence interval. Doing so can be particularly misleading when reporting to a public that is not aware that scientists commonly use a 95 percent confidence level to establish statistical significance. It is especially misleading since the lack of statistical significance in the trend at the 95 percent confidence level was related to the shortness of the time period over which the trend was calculated.
I am left with three possible inferences from the Crovitz piece:
- He never actually read the transcript from Jones’s interview and just cribbed from the Daily Mail. Tsk tsk.
- He does not understand statistics, in which case what is he doing writing about science?
- He has intentionally misled his readership.
I suppose there is a finite probability that I have got it wrong, and there is another explanation. My confidence level is only 80 percent so I guess I’m being a bit unconservative in this instance.
It Is Unequivocal — Just Look at Glaciers, Sea Ice, Permafrost, Earlier Springs …
So much of the arguments about global temperature trends focus on how to interpret temperature records from myriad weather stations. Indeed, a lot of the climategate controversy surrounding Jones was about a paper he wrote in 1990 trying to quantify the influence of urban heat islands based on weather stations in China.
The debate over the temperature record is important for establishing the magnitude of the warming but is unnecessary to establish that the globe is warming. The globe integrates the temperature signals from all those individual stations and provides very obvious, large-scale signs of climate change. What are those signs? How about melting glaciers? How about shrinking sea ice? How about earlier arrival of spring? How about melting permafrost?
And speaking of melting permafrost: this just out from the journal Permafrost and Periglacial Processes. Authors Simon Thibault and Serge Payette of Laval University in Quebec report on a study of permafrost extent near the James Bay area of Quebec.
Using a combination of aerial and ground surveys and historical aerial photographs, the authors concluded that permafrost in the region had retreated northward by about 130 kilometers (80 miles) over the past 50 years. They note that the changes they found are similar to the findings of numerous other permafrost studies, such as here and here. (See related article and photographs here, here, here, and here.)
Don’t believe it? Congratulations, you’ve joined the ranks of the skeptical ostriches with their heads buried deep in the melting permafrost.filed under: climate change, faculty, global warming, science
and: Climate Research Unit, climate science, climate skeptics, climategate, Daily Mail, glaciers, ice, Intergovernmental Panel on Climate Change, permafrost, Phil Jones, realclimate.org, sea ice, statistics, United Nations, University of East Anglia, Wall Street Journal