The pace of global warming is accelerating and the scale of the impact is devastating. The time for action is limited - we are approaching a tipping point beyond which the opportunity to reverse the damage of CO2 emissions will disappear.

I don't think Michael Bloomberg would say that his greatest skill is delivering the speech. He would say he's more of a nuts-and-bolts mayor-picking up the trash, dealing with the school system.

Companies that pollute should be taxed so that a product's cost to society is reflected in the price of that product.

It's time to let science and medicine, not politics and rhetoric, lead us to good, sound policy.

I think President Obama could have handled politics and policies differently. But he has been decisive, strong, and consistent - important qualities in a president. Mitt Romney is indeed an Etch A Sketch, the antithesis of leadership.

The reason to drive this point home with a vivid and frank comparison is many New Yorkers are still not confronting the reality of how serious our crisis is. It was an exhortation to face reality.

To every New Yorker - and to all those who believed in what I tried to stand for - I sincerely apologize.