The crisis is a concrete threatening reality today. It stands to get catastrophically worse unless we take action before the accumulation [of] this global warming pollution reaches such toxic levels that the problem becomes bigger than we can solve.

Well-established theories collapse under the weight of new facts and observations which cannot be explained, and then accumulate to the point where the once useful theory is clearly obsolete.

As human beings, we are vulnerable to confusing the unprecedented with the improbable. In our everyday experience, if something has never happened before, we are generally safe in assuming it is not going to happen in the future, but the exceptions can kill you and climate change is one of those exceptions.

I think I may have a future as a disembodied head.

Even if we give first priority to the destruction of terrorist networks, and even if we succeed, there are still governments that could bring us great harm. And there is a clear case that one of these governments in particular represents a virulent threat in a class by itself: Iraq. As far as I am concerned, a final reckoning with that government should be on the table.

When it comes to climate, we can all make a big difference.

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.