Right now, mostly because we've burned so much fossil fuel, the
atmospheric concentration of CO2 is 390 ppm—that's way too high, and
it's why ice is melting, drought is spreading, forests are dying. To
bring that number down, the first task is to stop putting more carbon
into the atmosphere. That means a very fast transition to sun and wind
and other renewable forms of power. If we can stop pouring more carbon
into the atmosphere, then forests and oceans will slowly suck some of it
out of the air and return us to safe levels. Is 350 politically possible?
It means switching off fossil fuel much more quickly than
governments and corporations have been planning. But we can change
that--if we mobilize the world to swift and bold climate action, and
shift the world to a clean energy future.