"Iowa State Climatologist Harry Hillaker said it's still hard to know with much confidence that burning fossil fuels is the primary driver for climate change"

Report: Midwest will suffer numerous effects from warmer weather - TwinCities.com

...Iowa State Climatologist Harry Hillaker said it's still hard to know with much confidence that burning fossil fuels is the primary driver for climate change.

"I think everyone would agree that there is certainly some impact," he said. "There still is a fair amount of disagreement among the climate community about the relative contribution, but it's certainly a significant one."

Land-use changes by humans also may be having a significant, if not larger, impact on climate change, Hillaker added.