WASHINGTON - March 11 - Nobel Prize-winning economists and scientists will deliver a letter to the U.S. Senate today, urging lawmakers to require immediate cuts in global warming emissions. The letter was signed by more than 2,000 prominent U.S. economists and climate scientists, including eight Nobel laureates, 32 National Academy of Sciences members, 11 MacArthur "genius award" winners, and three National Medal of Science recipients. 

"The nation's leading scientists and economists have joined together to tell policymakers that we agree about the urgency of addressing climate change now," said James McCarthy, one of the letter's organizers and a biological oceanography professor at Harvard University. "The bad news is the science of climate change is indisputable. The good news is we can cost-effectively cut the emissions that are causing it."

McCarthy is a former president of the American Association for the Advancement of Science, the chairman of the Union of Concerned Scientists (UCS) board, and a leader of the Nobel Peace Prize winning U.N. Intergovernmental Panel on Climate Change.

The longer the United States waits to address climate change, the more expensive it will be to reduce emissions and adapt to its effects, according to the letter, which among its signatories includes five Nobel Prize-winning economists.

One of those economists is Eric Maskin, a professor at the Institute for Advanced Study in Princeton, New Jersey. "The economic and social costs of global warming could be huge," Maskin said. "We need to act now to limit them."

Maskin and McCarthy were joined this morning in a telephone press conference by Alan Robock, a meteorology professor at Rutgers University, and U.S. Sen. Tom Udall (D-N.M.).

"As a scientist who has worked on this issue for my entire career -- more than a third of a century -- I can tell you every year of continued greenhouse gas emissions will lock us into larger widespread climate changes, with major negative consequences for most people on our planet," said Robock, a contributor to the Nobel Peace Prize winning U.N. Intergovernmental Panel on Climate Change.

Sen. Udall, who sits on both the Senate's Environment and Public Works Committee and the Commerce, Science and Transportation Committee, said Congress must make energy and climate legislation a top priority. "In addition to protecting public health and the environment," he said, "comprehensive legislation would reduce our dangerous dependence on foreign oil and enable American workers and businesses to lead the growing global market in clean energy technologies."

Today's letter was issued partly as a response to escalating attacks on climate science and disinformation about the costs of addressing global warming.

"In the economic emergency we are experiencing, some people think that we cannot afford to address the problem of climate change," said another letter signatory, Elinor Ostrom, an Indiana University professor and a Nobel Prize-winner in economics. "It's the other way around. If we don't act now, we will run into even greater economic problems in the future."

The letter, which was signed by 2,026 economists and climate scientists, concludes with the recommendation that the United States reduce global warming emissions "on the order of 80 percent below 2000 levels by 2050" and that the first step should be reductions on the order of 15 to 20 percent below 2000 levels by 2020.