A research paper in a prestigious journal that claimed to show a dramatic increase in global temperatures in the 20th century caused huge headlines around the world.
There’s just one problem. It’s not true
“Global Temperatures Highest in 4,000 Years,” blared the New York Times on March 7. The Times was reporting on what it called “the most meticulous reconstruction yet of global temperatures,” contained in a study published March 8 in the journal Science by Shaun Marcott, Jeremy Shakun, Peter Clark and Alan Mix.
However, once other scientists began looking into the data in the study, called “A Reconstruction of Regional and Global Temperature for the Past 11,300 Years,” the reconstruction began to look far less than meticulous.
The authors of the study quietly admitted last weekend that their claim of surging temperatures can’t be supported by their data. The establishment media outlets that reported the study with such fanfare have been largely silent on the stunning admission, although the Washington Post did report today that there is now a “controversy” over the data.
And, the New York Times has a climate blog posting that wonders “how the authors square the caveats they express here with some of the more definitive statements they made about their findings in news accounts.”
Stephen McIntyre of Climate Audit looked into the research and found the study’s authors had re-dated some of the samples used to determine the findings. Without the re-dating, the research would have shown no upswing in temperatures in the 20th century.
McIntyre emailed Marcott to ask how he got the conclusions in the Science article from the data in his dissertation. Marcott replied that his reconstruction of 20th-century temperatures was probably “not robust.” In other words, probably not accurate.
When that revelation became public, Marcott promised to clear up things in an online post. But when it finally appeared Sunday, Marcott admitted, “[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.”
In other words, the 20th century portion of their findings is useless.
