10:24am

Mon September 26, 2011
Environmental Watchdog

Switch to Natural Gas May Not Slow Climate Change

As federal policies make burning coal more expensive, many utilities—including Louisville Gas and Electric and Kentucky Utilities—are transitioning their older coal plants to natural gas. But a new study cautions that natural gas may not be a panacea to stop the effects of climate change.

Natural gas is cleaner than coal. When you burn it, it releases fewer pollutants into the environment. But a new study by National Center for Atmospheric Research climate scientist Tom Wigley says switching from coal to natural gas won’t halt climate change, at least in the short-term. He calls the transition a “double-edged sword.”

“On one hand, it would make the world a little warmer but on the other hand, it would reduce the effects of pollution,” Wigley said.

Phasing out coal would reduce the amount of carbon dioxide released into the atmosphere, but natural gas drilling and transporting results in a small amount of leaked methane.

“The leakage rate now might only be 2-5 percent,” Wigley said. “But that’s still significant because methane is such a powerful greenhouse gas.”

Also, sulfate aerosols released by coal burning reflect solar radiation back into space and actually have a slightly cooling effect on the atmosphere.

Wigley says his findings don’t mean that coal is better than gas, just that there are many factors other than carbon dioxide that should be considered when deciding climate policy.

Wigley’s paper is scheduled to be published in the peer-reviewed journal Climatic Change Letters next month.