Libertarian candidate and former New Mexico Gov. Gary Johnson, appearing on the Sunday program This Week, explained his 2011 comment that “in billions of years, the sun is going to actually grow and encompass the Earth…so global warming is in our future.”

“Can’t we have a little humor once in a while?” Johnson responded to host George Stephanopoulos when asked about the previous statement. “We should be prudent with the environment,” he said. “We care about the environment. Look, clean air, clean water. I think the [Environmental Protection Agency] exists to protect us against individuals, groups, corporations that would do us harm. Pollution is harm.”

Johnson has previously come out in favor of instituting a price on carbon.