Sen. James Inhofe (R-Okla.)Sen. James Inhofe (R-Okla.).Cross-posted from the Wonk Room.

A group of four Republican senators, led by climate denier Sen. Jim Inhofe (R-Okla.), have lashed out at the Obama administration’s efforts to protect the poorest and most vulnerable people of the world from climate disasters. Inhofe, Sens. John Barrasso (R-Wyo.), David Vitter (R-La.), and George Voinovich (R-Ohio) wrote a letter to President Barack Obama telling him to drop an international adaptation fund for the least developed nations — part of the Copenhagen Accord signed last year by Obama and over 130 other nations. Under Democratic leadership, the United States appropriated $1.3 billion for the climate fund in 2010 (compared to $136.8 billion for wars in Iraq and Afghanistan). After citing the budget deficit and high unemployment as reasons not to invest in protecting the vulnerable, the senators attacked the scientific basis for taking action:

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In addition, several of the findings of the UN’s Intergovernmental Panel on Climate Change (IPCC) concerning the eventual impacts of climate change in developing countries were found to be exaggerated or simply not true. We understand that reforms of the IPCC process are currently underway and we believe that no American taxpayer dollars should be committed to a global climate fund based on information that is not accurate.

The Wonk Room contacted the Climate Science Rapid Response Team, a new volunteer effort by top scientists, to find out what they thought about the claim that the threat to the developing world is too uncertain for the United States to act.

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“This is a dishonest climate change denier myth,” top climate scientist Michael Mann, director of the Penn State Earth System Science Center, explained. The senators are referring to two or three errors in the thousand-page impacts report that are “so insubstantial that they didn’t even make the summary for policy makers or the technical summary report.”

Dr. Gary Yohe, the Huffington Professor of Economics and Environmental Studies at Wesleyan University, charged the senators with “misdirection and misrepresentation”:

They are continuing an effort of misdirection and misrepresentation so that the debate does not focus on the issue — the urgent need for adaptation and the value to the United States of investing in adaptation (around the world).

Dr. Spencer Weart, a physicist and leading science historian, told us that “senators are incorrect in their claim that there are substantial errors in the IPCC’s evaluation of the science of impacts of climate change on developing nations”:

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Unless the senators can point to serious deficiencies in the actual main conclusions about impacts of the IPCC report — which they have not done and cannot do — the prudent thing is to take the IPCC’s severe warnings about impacts at face value and prepare accordingly.

The senators have received a collective $5.1 million from the fossil fuel industry in campaign contributions.

Dr. Weart’s full response debunks in detail the senators’ letter:

The senators are incorrect in their claim that there are substantial errors in the IPCC’s evaluation of the science of impacts of climate change on developing nations. The IPCC’s main conclusions, as carefully developed in summary statements, were endorsed with no dissent by all the scientists who participated (essentially comprising all the world’s experts in these matters) and also with no dissent by all the representatives of all participating governments (virtually every government in the world, including by the way the representatives appointed by the G.W. Bush administration).

What the senators are probably referring to are two statements buried among the many hundreds of detailed and specific statements in the body of the report. One of these claimed that Himalayan glaciers would disappear by the year 2035. This is rather obviously erroneous (ultimately it was traced back to a misprint in a non-peer-reviewed article that projected their disappearance by 2350). While the fate of the very high-altitude Asian glaciers remains uncertain, recent studies have shown that at least some of them are dwindling enough to have serious impact on South Asian water supplies within this century. In other developing nations, for example Peru, the harmful future impact of the disappearance of glaciers on water supplies has not been disputed, and is indeed already becoming a worry.

The second statement that the senators are probably thinking of had to do with the risk that the Amazon rain forest might dry up and turn to grassland by the end of the century. This is not an error if the statement is properly understood. There is indeed such a *risk* although since it is not a *certainty* it has been somewhat controversial. The most recent studies suggest that while climate change alone may not destroy the Amazon rain forest, the combined effect of climate change and continuing deforestation is indeed very risky.

In sum, unless the senators can point to serious deficiencies in the actual main conclusions about impacts of the IPCC report-which they have not done and cannot do-the prudent thing is to take the IPCC’s severe warnings about impacts at face value and prepare accordingly.