NASA Scientist Explains Why It’s Getting Warmer

By David DeWitte, The Gazette, Cedar Rapids, Iowa

Jan. 18–IOWA CITY — Americans can slow global warming without substantially altering their lifestyles, a leading climate scientist said Thursday, but the age of generating cheap electricity from coal will have to end.

Iowa native James Hansen, who testified against a coalburning plant proposed for Marshalltown on Wednesday, offered an overview of climate change to a large audience Thursday at the University of Iowa Center for Global and Regional Environmental Research.

While many politicians and policymakers still question the validity of global warming, to Hansen, director of NASA’s Goddard Institute for Space Studies, the big questions are resolved and the pressing issue is how best to minimize the damage.

Hansen said one problem is that political leaders don’t understand that the current increase in the mean temperature on Earth, just over a third of a degree Fahrenheit per decade, is actually a dramatic rise in historic terms.

Warming since the begin ning of the 20th century has been about 1.4 degrees Fahrenheit (0.8 degree Celsius), he said.

Looking at the history of Earth’s climate, “when there have been changes of climate of even 3 degrees Celsius, it has resulted in the extinction of species,” Hansen said.

In prepared testimony to the Iowa Utility Board, Hansen said that rate is causing an imaginary line on Earth’s latitude scale representing a given average temperature to move toward the poles at about 35 miles per decade.

Some species are moving with the changing climate, but others cannot migrate because their path is blocked by human habitation or other barriers, and they will become extinct, he said.

Carbon dioxide in Earth’s atmosphere has increased from 280 parts per million before the industrial age to about 385 parts per million. Hansen said slowing the increase to an acceptable rate will require reducing the concentrations to 325 to 355 parts per million.

The most practical way to achieve the reduction, he said, would be to eliminate the burning of coal in power plants unless the plants’ carbon dioxide emissions are captured and stored deep in the Earth or undersea sediments. Off-theshelf technology for capturing those emissions isn’t available, Hansen said, and would probably double the cost of power from coal plants.

“If we’re going to avoid really dramatic climate changes, we’re going to have to decide we can’t use coal,” he said.

Reducing emissions of methane and certain other gases responsible for climate change also will be necessary, Hansen said.

The good news in the lecture was that such changes are achievable. Hansen did not agree with questioners who thought the solution could be found in population control, or in conservation alone.

Hansen said a big enemy is utility regulation systems that allow utilities to profit more by increasing the amount of electricity they sell. He said the two states that have switched to systems of incentives for utilities that lower energy demand are making great strides in stemming energy demand.

Contact the writer: (319) 398-8317 or david.dewitte@ gazettecommunications.com

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