They haven't worked it out yet
Study: Climate change 'undeniable' - CNN.com
In the latest report scientists say climate change is undeniable. I don't deny climate change but I think the uncertainty lies in the possibility that man is capable of stopping or reversing the trend, or that the conclusion that man is wholly responsible for what is happening is a valid conclusion. The reality is we have neither been here long enough or have sufficient data to come to these conclusions. What did the caveman say ten thousand years ago when the ice started to melt? Our fires are responsible? No they said look how the grass grows.
This is a debate we really have to have. How far are we prepared to go to reverse the effects?
Are we prepared to depopulate the Earth?
Are we prepared to change our lifestyle?
Are we prepared to permit the failure of our economic systems?
I think the answer is no on all counts. Therefore, we have to adapt and that might mean being sensible about where and how we build our houses, what food we eat and just how much energy we have available to consume in any form