This is a quite questionable statement. There was a post here at HN a few days ago [1] and the article [2] says:

"Meanwhile, global warming lurches ahead. Greenhouse gas emissions continue to grow. So do solar and wind power. But do you know how much of the world’s primary energy comes from fossil fuels today? It’s 81 percent—the same as in 2006."

I didn't check the numbers by myself, but it sounds reasonable: while renewable sources grow, the consumption grows as well. So maybe we need nuclear power too in addition to solar/wind/etc? I don't see too much alternatives around.

[1] https://news.ycombinator.com/item?id=18411991

[2] https://blogs.scientificamerican.com/observations/why-we-nee...