Unless we redesign our civilization in numerous ways, all of the science in the world won't save us.

Carrying on as usual carries enormous risks, condemning today's students to a world of constant insecurity and frequent catastrophes.

Carbon-free energy is simply something we have to do. The time for talk is past. If we turn around net carbon emissions by 2020 rather than 2040, we get another 2° of fever rather than 3° - and that's a big difference.

Even if we stop the growth, we'd still be adding a constant amount of fossil carbon to the atmosphere each year.

Climate change has a very high procrastination penalty that just grows with each passing year of inaction - rather like what happens if you don't pay off your credit card. But for climate, there is no such thing as a fresh start from bankruptcy.

Stopping emissions growth represents the most minimal of do-something responses.

Since Serengeti-scale savanna scenes are only one or two million years old, our earliest after-the-apes ancestors didn't move into this scene so much as they evolved with it, as the slower climate changes and uplift produced more grass and less forest.