Climate Progress reports that "he’s the only Republican running for Senate who mentions climate change on his website. He used to support a carbon tax, and actually talks about conservative climate change solutions. Then, Jim Rubens signed the Koch brothers’ pledge not to do anything about it."
"The pledge, from the Koch-backed organization Americans For Prosperity (AFP), requires signers to “oppose any legislation relating to climate change that includes a net increase in government revenue.” That rules out a carbon tax, a policy that would make huge carbon cuts, create jobs, raise incomes, and improve the health of Americans. It’s also one of the few policies Congress could use to seriously fight climate change."