3C, Maybe. 5C, Possibly.

The British scientist who formerly chaired the Intergovernmental Panel on Climate Change (IPCC) says we've pretty much lost any chance of holding climate heating to 2C and now have just a 50/50 chance of staying within 3C.

The scientist, Professor Sir Robert Watson, chaired the Panel from 1997 until 2002, when he was ousted after US pressure for his removal.

Professor Watson says there is a 50-50 chance of preventing global average temperatures rising more than 3°C above their level at the start of the industrial age, but a 5°C rise is possible.  That would mean the Earth warming more than it has since the end of the last Ice Age.

“There are cost-effective and equitable solutions to address climate change, but political will and moral leadership is needed, and the changes in policies, practices and technologies required are substantial and not currently under way.”

“We now know we can’t rule out a possible 5°C temperature rise, and we need to start preparing for it.

“When I was chairing the IPCC we were all very optimistic that we’d have a global agreement to limit emissions, though we knew it would be difficult. But we were hopeful that emissions would not go up at the tremendous rate they are rising now.”