Two thousand US economists and climate scientists, including eight Nobel laureates, are sending a letter Thursday to the Senate urging lawmakers to require immediate nationwide cuts in greenhouse-gas emissions tied to global warming.

Emerging from a wintertime blizzard of bad press, US and international climate scientists are in damage-control mode, holding press conferences, firing off press releases, and affirming that global warming is quite real and that climate change science is up to snuff.

Despite the "climate-gate" hacked e-mail scandal and embarrassing mistakes in previous scientific reports, the bulk of research shows climate change is incontrovertible, they say.

"We call on our nation’s leaders to swiftly establish and implement policies to bring about deep reductions in heat-trapping emissions," the scientists write in the letter. "The strength of the science on climate change compels us to warn the nation about the growing risk of irreversible consequences as global average temperatures continue to increase."

That letter comes on the heels of Wednesday's announcement, by the United Nations secretary general and the chairman of the UN's Intergovernmental Panel on Climate Change (IPCC), that an international independent commission will conduct an independent review of all the IPCC’s "processes and procedures."

The move is the latest bid to try to shore up credibility for the IPCC, whose reports were tarred after hacked e-mails appeared to show bias in favor of global warming's severity during development of the panel's reports. Add to that glaring mistakes, such as the erroneous prediction in the IPCC's 2007 report (which won a Nobel prize) that Himalayan glaciers would vanish by 2035. In fact, the glaciers are melting about as fast as glaciers worldwide – about double the rate of 40 years ago, NASA has found.

Such revelations "have really shaken the confidence of the public in the conduct of science," Ralph Cicerone, an atmospheric scientist who heads the US National Academy of Sciences, said last month at a meeting of the American Association for the Advancement of Science. Recent polls show flagging public confidence that global warming is occurring. A recent Gallup poll shows 48 percent of Americans think the seriousness of global warming is exaggerated.

“The IPCC’s mandate is to provide objective scientific assessments for decision makers,” IPCC Chairman Rajendra Pachauri said in a statement. “The IPCC stands firmly behind the rigor and reliability of its Fourth Assessment Report from 2007, but we recognize that we can improve. We have listened and learned from our critics, and we intend to take every action we can to ensure that our reports are as robust as possible.”

The review will be conducted by the InterAcademy Council, the umbrella organization for the National Academies of Sciences, whose 18-member body includes top scientists from Argentina, Australia, Brazil, China, France, Germany, India, Indonesia, Japan, South Africa, Turkey, Great Britain, and the United States.

The letter-writing scientists say the bulk of climate science is sound and, "if anything, the climate problem is actually worse than reported earlier," wrote Leon Lederman, director emeritus of the Fermi National Accelerator Laboratory in Batavia, Ill., and a Nobel Prize winning physicist, in an individual statement in the letter to the Senate. "Physicists tend to be super critical of strong conclusions, but the data on global warming now indicate the conclusions are not nearly strong enough."