2 deg won't do!

Talks to limit global temperature rises to 2C will not prevent the possibility of dangerous climate change, says James Hansen, director of Nasa's Goddard Institute for Space Studies in New York. He was trying to tackle the widespread misconception among international climate negotiators meeting in Durban that 2C was a safe target.

He believes carbon dioxide concentrations – now at nearly 389 parts per million (ppm) – should be no higher than 350ppm to stop catastrophic events such as the melting of ice sheets, dramatic sea level rises and methane being released from beneath the permafrost.

"The target of 2C... is a prescription for long-term disaster," he said. "You can't say exactly what long term is but we are beginning to see signs of slow [climate] feedbacks beginning to come into play.

The emissions have to stop soon, Hansen maintains, if we want the planet as we know it.

Well, as the bargains continue at Durban, carrot sticks are being offered as tokens of climate consideration, but the seriousness of the challenge is simply not there.