Bill Broad vs. Al Gore

13 March 2007

Journalist William Broad recently wrote a column in the New York Times on Al Gore's film An Inconvenient Truth. I just wanted to point out a few of the problems I saw in the article.

First off, the article refers to Roger Pielke Jr. as an "environmental scientist." His area of expertise is political science, and he is not a scientist of any kind. But that's just a minor point that bothered me.

However, this part really bothered me:

So too, a report last June by the National Academies seemed to contradict Mr. Gore’s portrayal of recent temperatures as the highest in the past millennium. Instead, the report said, current highs appeared unrivaled since only 1600, the tail end of a temperature rise known as the medieval warm period.
Um, the NAS report actually did the exact opposite. It said that there is high confidence that the warming is unprecedented for the last 400 years, and that there is significant supporting evidence that the warming is also unprecedented for the last millenium:
The basic conclusion of Mann et al. (1998, 1999) was that the late 20th century warmth in the Northern Hemisphere was unprecedented during at least the last 1,000 years. This conclusion has subsequently been supported by an array of evidence that includes the additional large-scale surface temperature reconstructions and documentation of the spatial coherence of recent warming described above (Cook et al. 2004, Moberg et al. 2005, Rutherford et al. 2005, D’Arrigo et al. 2006, Osborn and Briffa 2006, Wahl and Ammann in press), and also the pronounced changes in a variety of local proxy indicators described in previous chapters (e.g., Thompson et al. in press). Based on the analyses presented in the original papers by Mann et al. and this newer supporting evidence, the committee finds it plausible that the Northern Hemisphere was warmer during the last few decades of the 20th century than during any comparable period over the preceding millennium.
The article also fails to mention that the IPCC AR4 report directly confirms what Al Gore said:
"Average Northern Hemisphere temperatures during the last half of the 20th century were very likely [>90% certainty] higher than during any other 50-year period in the last 500 years and likely [>66% certainty] the highest in at least the past 1300 years."
And this part really bothered me:
But Benny J. Peiser, a social anthropologist in Britain who runs the Cambridge-Conference Network, or CCNet, an Internet newsletter on climate change and natural disasters, challenged the claim of scientific consensus with examples of pointed disagreement.

“Hardly a week goes by,” Dr. Peiser said, “without a new research paper that questions part or even some basics of climate change theory,” including some reports that offer alternatives to human activity for global warming.
But Benny Peiser has presented this criticism before (in letters that were rejected by Science magazine), and has already been forced to back down once someone actually examined the articles he was citing as support. [Here's a paper by Naomi Oreskes in Science magazine that examines the scientific consensus]

Real Climate discusses inaccuracies in a previous article by William Broad here.
Real Climate discusses the article in more detail here.
Tim Lambert responds here.
Gristmill reponds here and here.
Media Matters goes into more detail on the "skeptics" used in the article here.
Boykoff's "Balance As Bias" paper can be found here.

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