For a long time David Attenborough did not believe in climate change. What does he think now? http://www.youtube.com/watch?v=S9ob9WdbXx0

The Vostock ice core ( a 3km long ice core from the Antarctic) has been analysed to show temperature and CO2 for the last 400,000 years. See how temperature rises as CO2 increases - and vice versa.

As you can see- CO2 levels have never in the last 400,00 years exceeded 300 ppmv

Levels today are around 380 ppmv.  The UK Met. office now foreasts 4oc  global warming by 2060 with    100c   in Arctic and Africa