On selfish grounds, the changes will be more than flooding in Tuvalu and Bangladesh.  Climate change will disrupt our agriculture (feeling hungry yet?), destabilize governments due to economic effects, increase the spread of tropical diseases, etc.

Failure is not an option.  Fortunately, many in the private sector are beginning to wake up to the threat, and address it in their own firms, and put pressure on the dinosaur Republicans to abandon Bush's "faith-based climatology."

As the situation becomes more desperate politicians will respond - they always wrap themselves in the flag in a crisis and blow the trumpets to charge.  

Hopefully enough leaders of science and industry - as well as the rest of us making evolutionary changes in our everyday lives - will already be in motion so that by the time the politicians notice that they're not leading the pack anymore, we'll all have made progress on the difficult road ahead.

What is the use of a house if you haven't got a tolerable planet to put it on? - Thoreau