UN scientist backs '350' target for CO2 reduction

PARIS (AFP) – The UN's top climate scientist has, for the first time, backed ambitious goals for slashing greenhouse gas emissions that many climate negotiators say are beyond reach.

"As chairman of the Intergovernmental Panel on Climate Change (IPCC), I cannot take a position because we do not make recommendations," Pachauri told AFP when asked if he supported poorer nations calling for atmospheric CO2 levels to be held below 350 parts per million (ppm).

"But as a human being I am fully supportive of that goal. What is happening, and what is likely to happen, convinces me that the world must be really ambitious and very determined at moving toward a 350 target," he said by telephone from New Delhi.

In its benchmark 2007 report, the IPCC said that the key for preventing dangerous global warming was to keep CO2 concentrations below 450 ppm.

Above that level, average global temperatures are likely, by 2100, to increase by more than 2.0 degrees Celsius (3.6 degrees Fahrenheit), a threshold G8 leaders agreed last month must not be crossed.

But a growing body of scientific evidence suggests that even these hard-to-reach goals may not be ambitious enough, prompting many of the nations most threatened by global warming to set the bar even higher.

More than 80 of the world's poorest and most climate-vulnerable nations have now declared that CO2 concentrations must be scaled back to below 350 ppm, and that temperatures cannot rise more than 1.5 C by century's end.

"I think this is a good development," Pachauri said.

"Now people -- including some scientists -- see the seriousness of the impacts of climate change, and the fact that things are going to get substantially worse than what we had anticipated."

Even at current CO2 levels of 385-to-390 ppm, severe impacts from climate change -- rising sea levels, drought, violent storms -- have started and are likely to get worse, experts say.