This week corporate and civic leaders from around the world will gather in San Francisco for the Global Climate Action Summit.

The effort was spearheaded by Gov. Jerry Brown to move the fight against global warming beyond the national commitments made in Paris nearly three years ago.

"Look, it's up to you and it's up to me and tens of millions of other people to get it together to roll back the forces of carbonization," says Brown in a promotional video for the summit.

It is likely to be Brown's last big climate event before he leaves office next year, and it comes at a time when many scientists agree that time is running out for a major counteroffensive against global warming, which Brown has repeatedly called an "existential threat."