Tony Blair has called for a "global environment revolution"

The former prime minister has been joining international experts on climate change in a bid to drive forward efforts to reduce global carbon emissions.

Mr Blair said: "We have reached the critical moment of decision on climate change. There are few if any, genuine doubters left.

"Even on the mildest application of the precautionary principles, failure to act on climate change now would be deeply and unforgivably irresponsible."