The strange world of climate research

While not a follow up on the climate change series this post will deal with the interaction between climate science and the media. About a month ago a new research paper by Shaun A. Marcott and others was published in the scientific journal Science:

They used the available proxy records to re-construct the global temperatures over the past 11 300 years. The accompanying press release by National Science Foundation:

prominently featured the following claims regarding the conclusions of the Marcott paper:

“The last century stands out as the anomaly in this record of global temperature since the end of the last ice age,” (…) What that history shows, the researchers say, is that during the last 5,000 years, the Earth on average cooled about 1.3 degrees Fahrenheit–until the last 100 years, when it warmed about 1.3 degrees F.

This point is illustrated by the following graph reproduced from the paper:


The graph shows a distinct uptick which represents the sudden rise in global temperatures in the last 100 years identified by Marcott et al. This finding was duly reported in the mainstream media as another indication that the recent rise in global temperatures is unprecedented.

The modern rise that has recreated the temperatures of 5,000 years ago is occurring at an exceedingly rapid clip on a geological time scale, appearing in graphs in the new paper as a sharp vertical spike.

After the ice age, they found, global average temperatures rose until they reached a plateau between 7550 and 3550 BC. Then a long-term cooling trend set in, reaching its lowest temperature extreme between AD 1450 and 1850. Since then, temperatures have been increasing at a dramatic clip: from the first decade of the twentieth century to now, global average temperatures rose from near their coldest point since the ice age to nearly their warmest, Marcott and his team report today in Science.

“In 100 years, we’ve gone from the cold end of the spectrum to the warm end of the spectrum,” Marcott said. “We’ve never seen something this rapid.

Then a climate sceptic, Steve McIntyre, looked into the statistics involved. In a series of posts on his blog, Climate Audit, he dismantled the claims made regarding the significance of Marcott et al in terms of the temperature record in the last 100 years. It turned out that not only the statistical methods used in the paper were inadequate to draw any conclusions about the recent global temperatures but also the uptick was an artefact of using curiously re-dated proxy records as input. For a technical explanation check out the link:

Steve’s findings got a significant publicity which the authors of the paper could not ignore. On the climate blog Real Climate they published a FAQ document containing the surprising admission:

Q: What do paleotemperature reconstructions show about the temperature of the last 100 years?
A: Our global paleotemperature reconstruction includes a so-called “uptick” in temperatures during the 20th-century. However, in the paper we make the point that this particular feature is of shorter duration than the inherent smoothing in our statistical averaging procedure, and that it is based on only a few available paleo-reconstructions of the type we used. Thus, the 20th century portion of our paleotemperature stack is not statistically robust, cannot be considered representative of global temperature changes, and therefore is not the basis of any of our conclusions.

So, we are now finding out from the authors of the paper that the 20th century uptick carries no statistical information. Why did they not say so when the media were falling over themselves to present their graph as another proof of accelerating global warming? Are all media outlets involved now going to publish corrections? Why it took a blogger who studies climate research as a hobby to spot a misrepresentation on this scale? Where were all the well paid climate scientists, journal editors and investigative journalists?


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