AAAS Joins Leading Scientific Organizations in Letter to Senators Reaffirming Scientific Consensus on Climate Change

As the U.S. Senate considers climate change legislation, AAAS joined with leading scientific organizations to send a letter to all senators reaffirming the scientific consensus that climate change is occurring and that greenhouse gases from human activities are the primary driver.

Sent 21 October and signed by leaders from 18 organizations, the letter states that conclusions based upon “rigorous scientific research” and “multiple independent lines of evidence” indicate that climate change driven by human activities is occurring and will have broad impacts on society, including the global economy and the environment.

In the United States, the letter said, this includes sea-level rise for coastal states, greater chances of extreme weather, regional water shortages and floods, and wildfires.

“The severity of climate change impacts is expected to increase substantially in the coming decades,” the letter says.

The organizations noted that a dramatic reduction in greenhouse gas emissions will be necessary to avoid serious impacts and warned that adaptation will be required to address impacts that are already unavoidable. Adaptation methods include improved infrastructure design, sustainable water management initiatives, modified agricultural practices, and improved responses to incidents of hazardous weather.

In June 2009, the U.S. House of Representatives passed its version of a climate change bill, H.R. 2454 authored by U.S. Representatives Henry Waxman (D-California) and Edward Markey (D-Massachusetts). Named the American Clean Energy and Security Act (ACES) of 2009, bill establishes a cap-and-trade program to reduce emissions 17 percent below 2005 levels by 2020 and 83 percent by 2050.

The U.S. Senate Environment and Public Works Committee, the first of several committees expected to take up the Senate's version of climate change legislation, is scheduled to begin its work later this month. Named the Clean Energy Jobs and American Power Act, the bill, S. 1733 authored by U.S. Senators Barbara Boxer (D-California) and John Kerry (D-Massachusetts), proposes a cap-and-trade program where polluters can buy and sell a finite number of allowances. It sets targets for short-term reductions in greenhouse gas (GHG) emissions at 20 percent below 2005 levels by 2020 and 83 percent by 2050.

While AAAS and the other signers are taking no positions on the bills, the letter is intended to remind lawmakers of the prevailing science and to offer scientific insight during the legislative process.

Benjamin Somers

21 October 2009