Clarion Caller

An interview with renowned climate scientist James Hansen

James Hansen, NASA’s top climate expert, believes scientists have an obligation to speak out when their findings have important implications for the public — and he certainly put that belief into practice last year when he told The New York Times that the Bush administration was trying to muzzle his calls for reducing greenhouse-gas emissions.

Hansen has been speaking publicly about the threats posed by climate change for more than two decades, though it’s only in the last couple of years that the public has begun to listen. These days, Hansen is the closest thing climate science has to a celebrity. Lately, he’s been using his star status to draw attention to the evils of coal-fired power plants and to chastise the Intergovernmental Panel on Climate Change for not making strong enough statements on sea-level rise.

Q. You have a new paper that will be coming out on the implications of peak oil in the climate debate. Can you tell us a little about the conclusions of that report?

A. The main point of that paper, which I think is fairly important, is that gas and oil already have enough CO2 in them to take us to approximately the dangerous level, and perhaps beyond the dangerous level. It’s pretty clear we’re going to use those fuels, and it’s not practical to capture the CO2 in oil since it’s used in mobile sources. Some of the CO2 from gas used in power plants, you could capture the CO2, but there are no plans to do that yet.

That means that the only way to keep CO2 from exceeding 450 parts per million would be to say we’ll have no more emissions from coal, and that would mean that we should not be building any more coal-fired plants until we have the sequestration technology. A molecule of CO2 from coal, in a certain sense, is different from one from oil or gas, because in the case of oil and gas, it doesn’t matter too much when you burn it, because a good fraction of it’s going to stay there 500 years anyway. If we wait to use the coal until after we have the sequestration technology, then we could prevent that contribution. I don’t think that has sunk in yet to policy makers, because there are many countries going right ahead and making plans to build more coal-fired power plants.

Grist