Risky business: Report says act now to combat climate change

By Doyle Rice, USA TODAY

By Stephen Lovekin, Getty Images

A report released Thursday by a National Research Councilcommittee cites "the pressing need for substantial action to limit the magnitude of climate change and to prepare to adapt to its impacts."

Since the effects of greenhouse gases can take decades to come about, and then persist for hundreds or even thousands of years, waiting for impacts to occur before taking action will likely be too late for meaningful mitigation, according to the report.

Beginning emissions reductions soon will also lower the pressure to make steeper and costlier cuts later. "It is our judgment that the most effective strategy is to begin ramping down emissions as soon as possible," said committee chairAlbert Carnesale of UCLA.

Substantial reductions of greenhouse gas emissions should be among the nation's highest priorities, the committee said.

"America's response to climate change is ultimately about making choices in the face of risk," says committee vice chairWilliam L. Chameides of Duke University.

The report, titled "America's Climate Choices," was commissioned by the U.S. Congress several years ago. It comes on the heels of a disastrous stretch of weather in the USA: The nation has been hit with five weather disasters costing more than a billion dollars each in 2011, setting a modern record for the most high-cost weather events so early in a year, according to insurance estimates and government records.

Is there a connection between these disasters and climate change?

"All extreme weather events are now subject to human influence," said Peter Gleick, a scientist at the Pacific Institute at a Capitol Hill briefing on Monday and reported by the National Resources Defense Council blog. "We are loading the dice and painting higher numbers on them," Glieck said.

The NRC committee deemed the risks of sticking to "business as usual" to be a much greater concern than the risks associated with a strong response.

The new report says that scientific evidence points to human activities -- primarily the release of carbon dioxide and other greenhouse gases into the atmosphere -- as the "most likely cause for most of the global warming that has occurred over the last several decades."

It adds that the trend cannot be explained by natural factors such as internal climate variability or changes in incoming energy from the sun. The report also notes that the impacts of climate change on human and natural systems can generally be expected to intensify with warming.