University of Michigan Arctic Ice Global Warming Study Criticized [Michigan Capitol Confidential]

A University of Michigan study released Tuesday claims shrinking snow and ice cover intensify global warming. But many skeptics question the conclusions and point to the limited amount of data over time that the researchers had available.
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Roy Spencer, a principal research scientist at University of Alabama-Huntsville, said scientists have only been measuring Arctic sea ice since 1979. He said researchers who start with the conclusion that is a “normal” period for temperatures could not be proven right or wrong.

“That is the mistake everyone makes in this business,” Spencer said. “You can’t prove them wrong. It is one thing to measure what has happened. But to figure out cause and effect is extremely different. Yet, that makes all the difference in the world when determining man-made global warming.”

Thermometer readings in the Arctic suggest that it was just as warm in the 1930s as it is now, he said.

“And it was way warmer in the Arctic thousands of years ago,” he notes. “How did that happen?”