Nasa climate expert makes personal appeal to Obama

• James Randerson, science correspondent
• The Guardian, Friday 2 January 2009

One of the world's top climate scientists has written a personal new year appeal to Barack and Michelle Obama, warning of the "profound disconnect" between public policy on climate change and the magnitude of the problem.

With less than three weeks to go until Obama's inauguration, Professor James Hansen, who heads Nasa's Goddard Institute for Space Studies, asked the recently appointed White House science adviser Professor John Holdren to pass the missive directly to the president-elect.

In it, he praises Obama's campaign rhetoric about "a planet in peril", but says that how the new president acts in office will be crucial. Hansen lambasts the current international approach of setting targets through "cap and trade" schemes as not up to the task. "This approach is ineffectual and not commensurate with the climate threat. It could waste another decade, locking in disastrous consequences for our planet and humanity," the letter from Hansen and his wife, Anniek, reads.

The letter will make uncomfortable reading for officials in 10 US states whose cap and trade mechanism - the Regional Greenhouse Gas Initiative - got under way yesterday. The scheme is the first mandatory, market-based greenhouse gas reduction programme in the US.

Hansen advocates a three-pronged attack on the climate problem. First, he wants a phasing out of coal-fired power stations - which he calls "factories of death" - that do not incorporate carbon capture. "Nobody realistically expects that the large readily available pools of oil and gas will be left in the ground. Caps will not cause that to happen - caps only slow the rate at which the oil and gas are used. The only solution is to cut off the coal source," the Hansens wrote.

Second, he proposes a "carbon tax and 100% dividend". This is a mechanism for putting a price on carbon without raising money for government coffers. The idea is to tax carbon at source, then redistribute the revenue equally among taxpayers, so that high carbon users are penalised while low carbon users are rewarded.

Finally, he urges a renewed research effort into so-called fourth generation nuclear plants, which can use nuclear waste as fuel.

Hansen argues that the current emphasis on reduction targets combined with carbon trading schemes make it too easy for countries to wriggle out of their commitments. He cites the example of Japan's increasing coal use, which it has offset by buying credits from China through the clean development mechanism - an instrument set up by the Kyoto protocol - yet China's emissions have continued to increase rapidly. China has overtaken the US as the biggest polluter in the world.

Hansen has been one of the most prominent advocates of action to tackle climate change since he first spoke on the issue in the 1980s. His testimony to the Senate featured in Al Gore's film An Inconvenient Truth and he has received numerous honours for his work on the issue, including the WWF's top conservation award.

Professor's wish list

• Moratorium on and phasing out of coal power stations without carbon capture, what Hansen calls the "sine qua non for solving the climate problem". Coal CO2 emissions are the same as those of other fossil fuels combined.

• Raising the price of emissions via a "carbon tax and 100% dividend". This is a tax mechanism to "decarbonise" the economy without a net take from taxpayers. Low carbon users are rewarded while high users are punished.

• Urgent research on "fourth generation" nuclear power with international co-operation. This offers one of the best options for nearly carbon-free power, according to Hansen. It would also help to solve the nuclear waste problem by using that material as fuel.