Spencer agreed that if Dessler's figures are correct, "then he is correct in his conclusion."
But, he cautioned, "the debate is how he got that number. He has a novel way of looking at the problem. We need to look into it."
Those are not the only problems scientists are finding with Spencer's research.
The Santer paper looked at Spencer's earlier claims - also oft-cited in arguments that climate science remains in flux - that climate models can't accurately recreate recent observed temperature trends. If the models can't create the present, the thinking goes, they aren't reliable at predicting the future.
That's wrong, Santer said.
In this case, Spencer "cherry picked" the data by using short, selective time-frames, he said.
"You wouldn't infer from minute-by-minute changes in the Dow (Jones Industrial Average) anything meaningful about the long-term, yearly behavior of the market," he added. "It's silly to look at an individual 10-year record and make inferences about the presence or absence of human impact on climate."
This article originally appeared at The Daily Climate, the climate change news source published by Environmental Health Sciences, a nonprofit media company.