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Jan. 24, 2008

Q & A: Professor James Hansen

Long before Al Gore’s Nobel Peace Prize, before the Kyoto Protocol, compact fluorescent light bulbs or hybrid cars, James Hansen was sounding the alarm on greenhouse gas emissions and bringing the world’s attention to the issue of climate change.

It was August 1981 when the journal Science published Hansen’s galvanizing paper, which concluded that carbon dioxide in the atmosphere would lead to global warming faster than prior predictions.

James Hansen
Professor James Hansen

Those 10 pages, riddled with equations, graphs and charts and bearing the bland title “Climate Impact of Increasing Atmospheric Carbon Dioxide,” became the shot heard ‘round the world in scientific circles. Its message has been reverberating ever since, ricocheting through the political landscape and becoming a clarion call for environmental activists and average citizens alike.

Hansen has taken more than his share of heat for his climate warnings. He has complained of being muzzled by presidential administrations, Democrat and Republican alike, who didn’t appreciate his conclusions, as they contradicted the nation’s energy policy. His 2006 battle on that score is the subject of a book published last month called Censoring Science: Inside the Political Attack on Dr. James Hansen and the Truth of Global Warming, by Mark Bowen.

Born and educated in the Midwest, Hansen lives and works on the Upper West Side, heading the NASA Goddard Space Institute for Space Studies (GISS), which is affiliated with Columbia. He also teaches earth and environmental sciences at the University.

Q. The 1981 analysis in the journal Science was one of the first public discussions about an increase in global temperature. Did you have any inkling how important your findings would be?

A. The broad long-term implications were pretty obvious. I worked on it more than a year to get it into a shape that Science would accept, submitting it at least three times, each time cutting the length about 15 percent, finally getting it to a length they would accept, even though it was twice what the editor kept saying was their size limit. I also sent it to Walter Sullivan, The New York Times reporter, who wrote an article on the front page, which got me in trouble with some colleagues and [the Department of Energy].

Q. It seems that you were among the few scientists talking about climate change for a long time. What was it like to be out there alone?

A. That’s not true. There were a lot of scientists working on climate. There were different threads, different approaches. For example, global modeling along the lines that GFDL [Geophysical Fluid Dynamics Laboratory], NCAR [National Center for Atmospheric Research] and GISS pursued. There were paleo-climate studies of the history of the Earth’s climate, and there were observations of on-going climate changes via satellites and other methods. But not as much interactions among these [researchers] as you would like. Now we have reached the point where you need to have your fingers into all of these if you want to develop insight quickly into how climate works and what the consequences of human forcings will be.

Q. A forcing is described as a disruption created by outside action. What kind of forcing are you referring to here?

A. A natural forcing is a change in the sun’s brightness. The largest human-made forcing is change of the amount of greenhouse gases in the air, gases that absorb heat radiation and make the planet warmer.

Q. Usually the media seizes on stories with doomsday scenarios. Why do you think it took so long for people to appreciate the danger of climate change?

A. Well, business-as-usual is doomsday. But the things that need to be done to avoid business as usual have many other benefits… Unfortunately, if special interests prevent us from taking an energy path that does not put all the fossil fuel carbon dioxide into the air, we will get at least part of doomsday. I think that we still have time to avoid that, but just barely.

 Q. Were you surprised at the government’s reaction to your findings?

 A. Well, not after my experience with DOE in 1981. They made it very clear that the government did not want to hear results that it did not want to hear.

Q. There is so much talk about climate change these days. Is the conversation where it should be?

 A. No, far from it. The special interests, with financial interests that they feel would be threatened, have succeeded in muddying the waters so much that the sensible actions, which would solve the problem and have many other benefits, are not being taken. Unfortunately, this is because special interests in Washington have undue sway over politicians. We should have statesmen in Washington—instead we have politicians.

Q. Did you ever consider leaving NASA to do research somewhere that would be more accepting of your conclusions?

A. No, NASA is the perfect place, because it has the capability to get much of the most critical data—and a can-do attitude.

Q. You’ve estimated that temperatures on Earth will be two to three degrees Celsius warmer at the end of the 21st century than they are now. That may not sound like a serious change to the layman. Can you explain why it is important?

 A. I do not think that global temperature will be two to three degrees Celsius warmer, because if it is, that is doomsday. I believe that it is still possible to wake people up, and we can move on to the world beyond fossil fuels. A warming that large would set us on a path toward sea level tens of meters higher, at least a few meters higher this century, with a continually changing coastline. That would be catastrophic. It would also spell the end for a substantial fraction of species on the planet.

Q. Do you have specific solutions to reduce greenhouse gas emissions?

 A. The phase-out of coal use over the next 25 years, except where carbon dioxide is captured, by itself would keep carbon dioxide below 425 parts per million, and warming less than one degree Celsius. That’s not enough, but it’s a large fraction of the solution.

Q. Can individual actions make a difference, or is climate change the kind of problem that can be solved only through government action?

 A. By far, the most important requirement is government leadership. What the individual can do is demand that. As long as we let people who are under the heavy thumb of special interests run the country, individual actions are meritorious, but they cannot solve the problem.

- Interviewed by Bridget O’Brian