The leading scientific group in the United States reported Wednesday that a “strong, credible body of scientific evidence shows that climate change is occurring” and is largely caused by human activity.
The National Academy of Sciences, which issued three reports relating to climate change on Wednesday, acknowledged that “certain Earth system processes” are not fully understood. But the group added that “it is clear” Earth’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.
The science academy does say there are unresolved questions surrounding climate research.
“Certain Earth system processes – such as ice sheet dynamics, cloud processes, and regional climate effects – 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.”
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 seemingly suffered 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 unsubstantial 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 that 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.
The other two reports are on possible ways to reduce the risks associated with climate change and how to adapt to the impacts already occurring.