Today I challenge our nation to commit to producing 100 percent of our electricity from renewable energy and truly clean carbon-free sources within 10 years.

Humanity is sitting on a time bomb. If the vast majority of the world's scientists are right, we have just ten years to avert a major catastrophe that could send our entire planet's climate system into a tail-spin of epic destruction involving extreme weather, floods, droughts, epidemics and killer heat waves beyond anything we have ever experienced - a catastrophe of our own making.

Today we're dumping 70 million tons of global-warming pollution into the environment, and tomorrow we will dump more, and there is no effective worldwide response. Until we start sharply reducing global-warming pollution, I will feel that I have failed.

The insistence on complete certainty about the full details of global warming-the most serious threat we have ever faced-is actually an effort to avoid facing the awful, uncomfortable truth: that we must act boldly, decisively, comprehensively, and quickly, even before we know every last detail about the crisis. Those who continue to argue that the appropriate response is merely additional research are simply seeking to camouflage timidity or protect their vested interest in the status quo.

I tell you that Michael Jackson is unbelievable, isn't he? He's just unbelievable!

The scientific evidence of how serious this climate crisis is becoming continues to amass week after week after week.

In the end, we must restore a balance within ourselves between who we are and what we are doing. Each of us must take a greater personal responsibility for this deteriorating global environment; each of us must take a hard look at the habits of mind and action that reflect - and have led to - this grave crisis.