Exxon Mobil head and Secretary of State nominee Rex Tillerson said “the risk of climate change does exist and the consequences of it could be serious enough that action should be taken” during his confirmation hearing before the Senate Foreign Relations Committee. He said he came to his “personal position over about 20 years as an engineer and a scientist. The increase in the greenhouse gas concentrations in the atmosphere are having an effect.”

“Our ability to predict that effect is very limited,” he added.

Tillerson said, if confirmed, he would not seek to single out career staff who had attended international climate change negotiations and said it’s important that “the United States maintain its seat at the table” internationally. He also expressed his personal support for a carbon tax to “simplify the system” of reducing greenhouse gases as long as “revenues go back out into the economy.”

He pointed out to committee members that “it’s important to note” President-elect Donald Trump asked for his position on climate change during early vetting.