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Environment

Hansen Renews Plea For Action

NASA climatologist urges curbs on growth of CO2 emissions

by Jeff Johnson
June 30, 2008 | A version of this story appeared in Volume 86, Issue 26

TWENTY YEARS AGO, James Hansen brought his concern about global warming to the U.S. Senate, testifying that Earth had entered a long-term warming trend and man-made greenhouse gases were almost certainly the cause. Among his predictions, he said global warming would hit both extremes in the water cycle—severe droughts and forest fires, with heavy rains and floods likely. His testimony was like lightning, igniting all sides of a growing climate-change debate.

Last week, on the anniversary of his June 23, 1988, testimony, Hansen, now the director of NASA's Goddard Institute of Space Studies, returned to Capitol Hill with similar charges but with a greater sense of urgency. Although climate change is much better understood today and fewer doubters remain, Hansen said, little has been accomplished to reduce carbon dioxide emissions, and time is running out.

In congressional testimony, interviews, and speeches, Hansen urged a "transformational change" in Washington to restrict carbon emissions. Otherwise, he said, it will become impractical to constrain CO2 to levels that prevent climate systems from passing a "tipping point" at which disastrous climate changes will spiral dynamically out of humanity's control.

According to Hansen, a safe level of atmospheric CO2 is 350 ppm, but today's levels are slightly higher than that and rising. He laid out several approaches that could make a small, near-term difference, such as reforestation and new agricultural practices, but said bigger changes are necessary.

Focusing on coal, Hansen urged a phaseout of its use, except where carbon is captured and sequestered underground, a technology in its infancy. And he would block construction of new coal-fired power plants.

Particularly critical of lobbyists and special interest groups, Hansen said that they had blocked transition to renewable energy sources. He urged that fossil energy company CEOs be tried for "high crimes against humanity and nature."

Hansen supports a carbon tax or what he calls a "tax and dividend" system that taxes oil, coal, and gas at the point of sale or port of entry. Income from the tax would be returned to the public as a dividend, with equal amounts going to each adult and half-shares to each child, he said.

But when it comes to climate-change politics, contradictions abound. As Hansen spoke, members of Congress debated legislation to increase oil production and availability to help industry and consumers avoid the pain of high oil and gasoline prices. However, that pain has resulted in a decline in U.S. gasoline consumption for the first time in 17 years, says a June 19 study by Cambridge Energy Research Associates. The Cambridge researchers predicted the drop may be permanent because consumers are turning to more efficient vehicles.

Petroleum is the largest source of U.S. CO2 emissions, and coal is a close second. Together they make up about 80% of energy-related CO2 emissions.

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