In 2007, APS adopted an official statement on global warming:[21]
Emissions of greenhouse gases from human activities are changing the atmosphere in ways that affect the Earth's climate. Greenhouse gases include carbon dioxide as well as methane, nitrous oxide and other gases. They are emitted from fossil fuel combustion and a range of industrial and agricultural processes.
The evidence is incontrovertible: Global warming is occurring.
If no mitigating actions are taken, significant disruptions in the Earthâs physical and ecological systems, social systems, security and human health are likely to occur. We must reduce emissions of greenhouse gases beginning now.
Because the complexity of the climate makes accurate prediction difficult, the APS urges an enhanced effort to understand the effects of human activity on the Earthâs climate, and to provide the technological options for meeting the climate challenge in the near and longer terms. The APS also urges governments, universities, national laboratories and its membership to support policies and actions that will reduce the emission of greenhouse gases.
In November 2009, 80 current and past members of the American Physical Society presented a letter to the society specifically objecting to the society's position.[22] A few days later, it was rejected.[23] On April 18, 2010, the APS reaffirmed the 2007 statement with commentary to provide further support.[21]
The following individuals resigned their memberships over disagreement with the society's official statement on global warming:
Ivar Giaever, Winner of the Nobel Prize for Physics in 1973, resigned 13 September 2011.[24]
Harold Lewis, Emeritus Professor of Physics and former department chairman at the University of California, Santa Barbara, resigned 6 October 2010. His letter argues that APS's cupidity is what is keeping it from changing its opinion on global warming.[25]
http://en.wikipedia.org/wiki/American_Physical_Society#Statement_on_global_warming