Despite the Trump administration’s decision to pull the U.S. out of the Paris Climate Agreement, more and more nations — and communities in America — are looking to increase their renewable energy use.

And one team of scientists believes that direction makes a lot of sense on many levels. Their study describes how 139 nations could completely run on renewable energy as soon as 2050.

To learn more, we spoke with Stanford University’s Mark Z. Jacobson. He led the team and is director of the Atmosphere/Energy program.