Worldwide investment in renewable energy is growing exponentially—confounding experts who said it would never happen—says Achim Steiner, Executive Director of the United Nations Environment Programme (UNEP).

Steiner, a German development expert who has run UNEP since 2006, spoke April 1 at an event sponsored by the Atlantic Council’s Global Energy Center. His conversation with the center’s Founding Director, Richard L. Morningstar, coincided with the release of a UNEP report, Global Trends in Renewable Energy Investment 2015.

“Renewable energies are becoming accessible for developing economies,” Steiner said. “This is not just a matter of not using oil revenues, but leapfrogging technology. It is happening before our very eyes.”