The blogosphere has been much abuzz about the implications of the finding reported last week in Nature magazine that Antarctica, on average, has warmed over the past 50 years.
An author of the report explained to the Associated Press that their findings were especially significant because “contrarians” had latched onto the idea that Antarctica has been cooling, and thus “bucking the trend [of global warming].” The “contrarians” meanwhile, caught somewhat off-guard, mounted a seemingly confused defense focused on attacking the methodology employed to reach such a conclusion rather than the actual contention itself.
I’ll try to cut through the spin and confusion to get at the real implications of the study (which turn out not to be terribly exciting).
A research team led by University of Washington’s Eric Steig used what they deemed to be a more intelligent method for interpolating the temperature patterns between the few long-term observing stations sprinkled across Antarctica than other previous attempts at producing a continental temperature history (there are only about 15 observing stations with data back into the late 1950s across continent a bit larger than the United States). The complex statistical technique related the temperature patterns from the observing stations to temperature patterns revealed at higher spatial scales by satellites which had been collecting data over Antarctica for the pat 25 years or so. In this way, the researchers gained a better understanding of what the sparse surface observations may reveal about the broader patterns of temperature across the continent. They assumed these relationships to be valid in period prior to satellite observations and thus they developed a higher resolution picture of how the temperature varied across the continent from the late 1950 to the early 1980s than had previously been possible. All in all a reasonable approach to the problem—but likely not the final word on the matter.
The end result of Steig et al.’s analysis was that they documented a greater temperature increase from 1957 to 2006 than had previously been established. But, that said, almost all previous analyses did find some degree of warming in Antarctica starting in the late 1950s (the time when consistent temperature observations first were recorded). So, in this sense, the new findings just firmed up our general understanding, they certainly didn’t buck any standing trends (Figure 1).
The cooling (or, at least, lack of warming) in Antarctic was not supposed to have begun in the late 1950s, but rather the 1970s. In other words, it has been understood that there has been little, if any, warming averaged across Antarctica as a whole for the past 20 or 30 years. This is not to say that no areas of Antarctica have warmed during that time, just that when averaged together across the continent, there has been little overall temperature change. The new Steig et al. results basically confirm that understanding as well (Figure 1, again).
The bottom line here is that the new findings reported by Steig and colleagues do more to shore up our basic understanding of how large-scale temperatures have evolved across Antarctica during the past 50 years than they do to topple any long-standing beliefs.
The hubbub surrounding them arose from the contention that the results undermined a long-held skeptic position accompanied by a confusion by the skeptics as to exactly what their long-held position actually was (or should have been).
I think that once everybody calms down, this incident will prove to be much abuzz about nothing.
(In case anyone is wondering, climate models are all over the place when it comes to what their expectations are of the temperature behavior of the Antarctic region for the past 50 years. So you can’t confidently use Antarctica’s temperature history to either confirm or refute climate model behavior in general. Into the future, as the ozone hole wanes and the greenhouse effect waxes, there is a general expectation that Antarctica will warm—so more robust comparisons can potentially be made a few years down the road.)
Steig, E. J., et al., 2009. Warming of the Antarctic ice-sheet surface since the 1957 International Geophysical Year. Nature, 457, 459-463.
I appreciate your balanced take on our paper. It’s refreshingly well done. Thanks! It is worth noting that while you are right that our paper isn’t very “exciting” — i.e. it doesn’t address “global warming”, much as the reporters I’ve talked to and the various climate-change-conspiracy bloggers would like it to — the reason it was published in Nature was *not* because it “topples long-standing beliefs” but because it answers a fundamental question: “what has West Antarctica been doing?” Our answer — that it is warming like the Antarctic Peninsula — is of great interest to Antarctic climate scientists and glaciologists. None of the pundits know what to do with this, so it didn’t get much mention. Yet it is the chief finding of our paper, as I think we made very clear in the text.
Chip, seems to me that you’re downplaying both the evidence for a long-term rise in Antarctic temperatures and the rather narrow way that “skeptics” have been trumpteing the medium term “cooling” that the CFC-induced ozone hole has caused.
In aggregate, the picture of a warming Antarctica seems clearer all the time.
read the paper and realise that the warming was all before the 80’s. 30 years is the period that is trumpeted by the warmers as enough time to see a trend. I see a FLAT trend for Antarctica. What do YOU see??
Of course, they had to use questionable statistical methods with their data “creation” to even get a FLAT trend!!
By the way, where is you DATA that shows the ozone hole was caused by Anthropogenic activity?? There is a new study that found a quite different lifespan for one of the primary Anthropogenic causes. They are scrambling to cover this hole in the theory right now!!
Basically Anthropogenic causes are a pimple on the earth. Until you warmers understand this you will be running around screaming Death and Destruction and destroying wealth faster than Socialism and for even less reason!!!
And ‘downplaying’ might just be exactly what’s needed when you have a planet in a state of hysteria.
The IPCC believes it does not need CO2 to explain any warming that occured BC (before the Birth of CO2 in 1979) . I don’t see any warming since then. Not in Antarctica. Something is wrong with the concensus. At least in Antarctica.
Some dismiss the MWP and the LIA as Northern hemisphere phenomena despite mounting evidence to the contrary. Could this be the case with recent warming.