Gavin Schmidt, director of NASA's Goddard Institute for Space Studies, has taken the unusual step of personally telling Senator Malcolm Roberts he was "mistaken" in his claim that the agency had falsified key data to exaggerate warming in the Arctic. He expressed surprise that Roberts had actually been elected as a Senator.
"You appear to hold a number of misconceptions which I am happy to clarify at this time," Schmidt wrote to Roberts. "The claim that GISS has 'removed the 1940s warmth' in the Arctic is not correct."
Roberts wrote to NASA on November 14, asking about the agency's temperature calculations, saying they had "influenced" the Intergovernmental Panel on Climate Change's warnings on global warming that in turn had swayed Australian government policy.
Roberts, a former coalmine manager, rejects the idea that climate change is related to carbon dioxide levels or human intervention.
"In Australia, we have considerable concern about temperature adjustments made by NASA over many years," Roberts wrote to NASA. "In dropping the temperatures for the early period, the [Arctic] warmth for the 1930s and 1940s appears to have been removed. What is your specific reason for doing this?"
The claim that NASA tampered with Arctic data from the 1930s and ’40s is a popular conspiracy theory among climate change deniers, who argue the current increase in temperatures — especially at the North Pole, where the temperature is “a crazy” 20°C above normal — is not exceptional and so action to address climate change is unnecessary.
"We are certainly gratified by the attention Australia pays to our analysis,” Schmidt wrote to Roberts. “But in case you have remaining questions, I urge you to perform your own analyses."
Truasti Jonsoon, senior meteorologist with a specialty in historical climatology at the Icelandic Meteorological Office, told Roberts in an email any temperature "adjustments" are "quite sound".
"I assure you that these adjustments are absolutely necessary and well-founded although the finer details of the resulting series shown in your letter differ slightly from my own version," he wrote.
Schmidt told Fairfax Media he was not surprised that the query about Arctic temperatures was coming from Australia. "The insistence that the data must've been inappropriately adjusted [is what the sceptics say] all the time,” he said. “[It's] pretty much the definition of denial.
"I'm aware of who Malcolm Roberts is, and the only surprise is that he is in fact a senator.”