The urgency derives from the nearness of climate tipping points.

If we fail to act, we will end up with a different planet.

Because cap and trade is enforced through the selling and trading of permits, it actually perpetuates the pollution it is supposed to eliminate.

As you get more global warming, you should see an increase in the extremes of the hydrological cycle - droughts and floods and heavy precipitation.

I was lucky to grow up at a time when it was not difficult for the child of a tenant farmer to make his way to the state university.

The last time the world was three degrees warmer than today-which is what we expect later this century-sea levels were 25m higher. So that is what we can look forward to if we don't act soon.

The greatest danger hanging over our children and grandchildren is initiation of changes that will be irreversible on any time scale that humans can imagine.