Democratic Senator Martin Heinrich is the son of a utility lineman, and one of just a few engineers in Congress.

Clean energy piqued the New Mexico lawmaker’s interest at an early age, while he was building and racing solar-powered cars in college. But for most of his life, he says, it was hard to imagine a world in which renewables could power more than 20 or 30 percent of the electric grid.

Today, Heinrich’s outlook is different. “We can have a future reliable, cheap, resilient grid that is 100 percent powered by clean energy,” he said in an interview on Greentech Media’s Political Climate podcast.

Our analysis suggests that the Earth System may be approaching a planetary threshold that could lock in a continuing rapid pathway toward much hotter conditions—Hothouse Earth.

Humanity is now facing the need for critical decisions and actions that could influence our future for centuries, if not millennia.