April 22, 2005

The Tip of the Iceberg: Yet another Predictable Distortion

This Earth Day, AP newswire leads with a real scare story: “Study Shows Antarctic Glaciers Shrinking.” In doing so, the press, yet again, predictably distorted a global warming story.

By “Antarctica” they actually meant the Antarctic Peninsula, which comprises about 2% of the continent. It’s warming there and has been for decades. But every scientist (or for that matter, everyone who has read Michael Crichton’s State of Fear) knows that the temperature averaged over the entire continent has been declining for decades.

The underlying science behind the AP story was published in the April 22, 2005 issue of Science magazine, under the more appropriate (and accurate) title, “Retreating Glacier Fronts on the Antarctic Peninsula over the Past Half-Century.” A research team led by Alison Cook of the British Antarctic Survey carefully measured the historical position of 244 glaciers as determined from a 60-year collection of images including aerial photographs and satellite pictures. By comparing the position of glacier termini over time, the researchers were able to determine the timing and speed of glacial changes.

The results presented in Science weren’t even based on the entire Peninsula, but rather the northern portion. While a more comprehensive continent-wide investigation of coastal glacier changes is underway, only the results from the Peninsula were written up.

Figure 1 shows the temperature trends from 1966-2000 over Antarctica as reported in a study by Peter Doran and colleagues and published in Nature magazine in 2002. The region that encompasses all 244 of the glaciers in the Science study is highlighted. While it is clear the there has been warming in the localized region around where the Antarctic Peninsula glaciers are located, it is also clear that the majority of the rest of the continent has been cooling. Just how much has been cooling was also calculated by Doran (Figure 2), and shows that about 2/3rds of the continent outside of the Peninsula has been cooling over the past 35 years or so.

Antarctic Temperature Trends

Figure 1. Trend in annual temperatures in Antarctica with the glacier study region outlined by the red box (adapted from Doran et al., 2002).

Antarctic Temperature Trends

Figure 2. Proportion of Antarctica that is warming (as indicated by the + signs) and cooling (as indicated by the – signs). Annually, temperatures have been cooling in 65.9% of the region outside of the Antarctic Peninsula (from Doran et al., 2002).

Furthermore, studies have been made investigating the overall status of sea ice around Antarctica. NASA announced the results of their study in 2002 with a press release headlined “Satellites Show Overall Increases in Antarctic Sea Ice Cover.” While there are regional variations from this trend, including a decline in sea ice around the Antarctic Peninsula, the area of sea ice around much of the remainder of the continental margin has been increasing, at least over the past 25 years. Obviously, a story proclaiming “Antarctic Sea Ice Rapidly Diminishing” and focusing on the Peninsula region would paint an incomplete and unfair picture of the actual circumstances there.

The fact that a report that glaciers are melting over one extremely small portion of Antarctica that is showing warming, while the rest of the continent is cooling, grabs not only newspaper headlines but finds its way without a regional perspective into a prestigious publication like Science is troubling. If objectivity, rather than scariness were the purpose, Cook et al. would certainly have referenced Doran’s work for background. Or perhaps the editors at Science could have asked for it?

The general cooling of Antarctica is highly scientifically significant because climate models run under increasing levels of greenhouse gases predict that the Antarctic continent as a whole, not just the Peninsula, should be rapidly warming. This is clearly a model failure and no amount of going on and on about the impact of warming in the Peninsula, is going to change that fact.

There’s a 2004 book that details the repetitive nature of global warming exaggeration, called Meltdown: The Predictable Distortion of Global Warming by Scientists, Politicians, and the Media. If it were still being written, the sad story of Earth Day, 2005, would have surely merited a chapter.

References:

Cook, A.J. et al., 2005. Retreating Glacier Fronts on the Antarctic Peninsula over the Past Half-Century. Science, 308, 541-544.

Doran, P.T., et al., 2002. Antarctic climate cooling and terrestrial ecosystem response. Nature, 415, 517-520.

Michaels, P.J., 2004. Meltdown: The Predictable Distortion of Global Warming by Scientists, Politicians and the Media. Cato Books, Washington DC. 272pp.




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