Credit: Goddard Institute of Space Studies
JAMES HANSEN IS NOT an easy man to pin down. He may be the world's most renowned climate scientist, and almost certainly its most confrontational, but he keeps his tracks well camouflaged.
His office is situated in an anonymous and shabby brownstone apartment block on a side-street, off New York's Upper West Side. It is above Tom's Diner, the restaurant that achieved fame in the TV comedy series Seinfeld. Thousands of tourists swing by here every year, but most pay little attention to the crumbling doorway beside it.
This entrance turns out to belong to NASA's Goddard Institute of Space Studies where Hansen, its director, and his staff analyse the impact of greenhouse gases using data relayed from thousands of collection points around the world, including satellites and polar bases.
These have shown that our planet has gone through a 0.6ºC rise in temperature since 1970, with the 10 hottest years having occurred between 1997 and 2008: unambiguous evidence, Hansen believes, that Earth is beginning to dangerously overheat thanks to the carbon dioxide we are pumping into the atmosphere.
He turns out to be a dry, soft-spoken, rather self-effacing man who, in his green jumper with elbow pads, cords and check cotton shirt, has the look of a careful, tweedy academic. His office is dominated by a battered black-leather sofa, mounds of paperwork, an old globe of the Earth and large, dusty bookcases that cover three walls. Both room and occupant exude old-fashioned studiousness.
This is no out-of-touch academic, however. Hansen appeared in Al Gore's film, An Inconvenient Truth, and is a winner of the World Wide Fund for Nature's top conservation award. He has also proved to be a remarkably doughty opponent of those who deny the dangers of global warming, including the administration of President George W. Bush, which, rashly and unsuccessfully, attempted to censor Hansen's warnings.
For such individuals, and the rest of the world, Hansen has a terse and unambiguous message about the dangers posed by industrial carbon emissions, particularly those produced by coal - by far the dirtiest, most dangerous emitter of greenhouse gases.
"Coal is the single greatest threat to civilisation and all life on our planet," he states. Coal-powered electricity stations are "factories of death". It is a blunt message and the physicist has gone to considerable pains to make sure the world hears it. Apart from his rows with Bush, his appearances before U.S. Senate committees and his TV interviews, Hansen has flown round the world to support the causes of dozens of climate-change protesters.
And then there are those letters to leaders of the U.S., France, Britain, Germany, Japan and Australia - presidents and prime ministers who have been told, in no uncertain terms, of the error of their ways. For example, Hansen recently wrote to Australia's Kevin Rudd to tell him "your leadership is needed on a matter concerning coal-fired power plants, a matter with ramifications for life on our planet." Halt all construction of coal-power plants, he urged Rudd, a message that seems to have fallen on deaf ears.
"The current Australian government was elected on a platform that it was going to deal with climate change, which was clearly having an effect on the country. But what it has done - thanks to industry which has a powerful influence there - is set the goal for limiting carbon dioxide emissions so high, it guarantees there will be no effective reductions on emissions," says Hansen, a message he has repeated in several more letters to the Australian government in 2009.
