When you look at what has happened over the last few decades the natural fluctuations point in the opposite direction of what has actually occurred. When they run the models and plug in the man-made pollution, the correspondence is exact. Beyond that, the scale of natural fluctuations has now been far exceeded by the impact of man-made global warming.

The truth is that we're at a critical juncture in the history of our species and if we don't act soon, we could inhabit a world we don't recognize anymore. But the most important truth is that we are capable of stopping climate change before the worst of its consequences are locked in. The solutions exist - all we need is the will to do something about it.

Well, the title "An Inconvenient Truth" is a way of highlighting the reasons why some people, including the president, don't seem to accept the truth.

When energy prices go up, the difficulty of projecting demand also goes up - uncertainty goes up.

Earlier in this century, the Heisenberg Principle established that the very act of observing a natural phenomenon can change what is being observed. Although the initial theory was limited in practice to special cases in subatomic physics, the philosophical implications were and are staggering.

Having cameras follow you is something that requires a little personal adjustment, but you actually do begin to forget they're there. It's impossible to maintain that awareness all the time, and when you're going through an emotional or absorbing experience, you really don't have any spare attention to think, "Got to remember that the camera is rolling."

I'm naturally an optimist, but my basis for hope is rooted in my understanding of human nature.