Sen. John Kerry (D-Mass.) said Wednesday that a major new scientific
report on global warming demonstrates the “urgency” of passing the
climate change and energy bill he unveiled last week.

The National Academy of Sciences (NAS) released a study Wednesday that concludes there is powerful evidence that climate change is occurring and human activities are a major reason why.

{mosads}“This is yet another wake-up call on the threat of global climate change,” Kerry said in a prepared statement. “These studies clearly demonstrate the urgency for Senate action on the American Power Act.”

The bill that Kerry unveiled with Sen. Joe Lieberman (I-Conn.) aims to cut U.S. emissions by 17 percent by 2020 and by more than 80 percent by 2050 by imposing new limits on industrial polluters and expanding development of low-carbon technologies.

“Climate change is occurring, is caused largely by human activities and poses significant risks for — and in many cases is already affecting — a broad range of human and natural systems,” states one of three NAS reports released Wednesday.

The other reports address steps needed to curtail emissions and strategies for adapting to changes that will inevitably occur and are already under way, such as rising sea levels and increased intensity of some extreme weather events.

“This is yet another wake-up call on the threats of global climate change,” Kerry said.

In its report, the National Academy of Sciences said that although “certain Earth system processes” are not fully understood, “it is clear” that the planet’s future climate will be markedly different from what it has been for the last 10,000 years.

Environmental groups used the report to refute claims pushed by climate change skeptics that the so-called Climategate e-mail controversy and errors in the United Nations report on global warming undercut evidence that burning fossil fuels is altering the climate.

“This report should put to rest the unfounded contrary assertions advanced by special interests and help clarify the fact that our nation’s most distinguished scientists are unified in their support of this core message: Man-made climate change is real and we need to address it now,” said James McCarthy, a biological oceanography professor at Harvard University, in a statement released by the Union of Concerned Scientists.
UCS is a backer of climate legislation in Congress.

Among the unresolved questions surrounding climate research the Academy identifies are “ice sheet dynamics, cloud processes and regional climate effects.” Such “Earth system processes” are either “incompletely understood or not fully resolved in current climate models, leading to uncertainties in the magnitude and rate of global climate change and its manifestations at local and regional scales,” according to the Academy.

{mosads}But the report adds: “Despite these uncertainties and complexities, it is clear that Earth’s future climate will be unlike the climate that ecosystems and human societies have become accustomed to during the last 10,000 years, leading to significant challenges across a broad range of human endeavors.”

The effort to pass climate legislation in Congress appeared to suffer a blow late last year when a number of hacked e-mails from the Climate Research Unit at the University of East Anglia in the United Kingdom were released.

The e-mails seemed to show climate researchers trying to hide data that didn’t support their conclusions, but initial investigations have found the e-mails don’t undercut the science supporting human-caused climate change.

Meanwhile, errors in the United Nations Intergovernmental Panel on Climate Change report — such as an unsubstantiated claim about the pace of glacier melt in the Himalayas — added to the controversy.

Gallup reported in March that a survey it conducted showed fewer Americans believed climate change was real, although a majority still believed it was.

The Academy says, however, that “science has made enormous progress toward understanding climate change.”

Although it is not possible to predict how a changing climate will affect different regions, the effects could also be more severe than projected and the danger warrants action, the Academy said.