Climatologist says U.S. must scrap new coal power plants

Carbon dioxide levels in the atmosphere are already too high and plans to burn remaining coal and oil reserves should be scrapped, said James Hansen, director of NASA's Goddard Institute for Space Studies.

Coal-burning power plants increase concentrations of carbon dioxide, which contributes to global warming by trapping heat close to the earth. Companies such as Duke Energy Corp., planning to build new coal plants, don't "appreciate the gravity of the situation," Hansen's report says.

Hansen, who in 1981 warned that global warming emissions were heating the planet faster than expected, will submit his latest research this week to the journal Science, he said in an e-mail. "Catastrophic climate change" can still be avoided through conservation and greater use of renewable energy.

"It has become clear that continued emissions carry great danger," Hansen wrote in a March 25 letter to James Rogers, chief executive officer of Duke, based in Charlotte, N.C. "If you insist that new coal plants are essential for near-term power needs, you may submit your company and your customers to grave financial risk, and leave a legacy that you will regret."

Scientists continue to debate how much carbon can be pumped into the atmosphere before the worst effects of climate change, including droughts, floods and reduced fresh water supplies, become irreversible. Concentrations of carbon in the atmosphere are about 385 parts per million.

The European Union says that global warming needs to be kept to 2 degrees Celsius (3.6 Fahrenheit) to avoid the worst effects of climate change. A scenario to stay below that limit suggests that carbon levels must be stabilized between 350 and to 400 ppm.

"What this paper makes clear is that we have already passed the level of atmospheric CO2 that we can afford to leave in the air in the long run," Hansen said in an e-mail. Carbon can be reduced below "the dangerous level this century, but only if, over the next few decades, we phase out coal plants that do not sequester their carbon dioxide."

Carbon sequestration involves capturing the gas and injecting it for storage underground. The technology is being developed at a handful of pilot programs, and has yet to be demonstrated at commercial scale.

In his letter, Hansen applauded Rogers for public statements that "recognize the climate problem," and noted that Rogers attended a talk on climate change in November in Charlotte. Hansen provided his latest research, "Target Atmospheric CO2: Where Should Humanity Aim?" with the letter.