In a HARDtalk interview broadcast on 30th September 2009, Stephen Sackur talks to Sir David King.
From 2000 to 2007 Sir David was the UK's Chief Scientific Adviser.
Five years ago he described climate change as a greater threat to the world than terrorism.
Now his warnings are even more stark.
With the climate change summit in Copenhagen just over two months away is there a disconnect between the science and the politics of climate change?
Stephen Sackur talks to Sir David King
This interview will be shown on BBC World News at 0330 (except Middle East and South Asia), 0830, 1430, 1830, 2030 and 2230 GMT (except Middle East and South Asia)
HARDtalk is also broadcast on the BBC News channel at 0230, 0430 & 2330