Earth Policy Institute
http://www.earth-policy.org/
The Earth Policy Institute (EPI) was founded in 2001 by Lester Brown, the founder and former president of the Worldwatch Institute, to provide a plan of a sustainable future along with a roadmap of how to get from here to there.

Intergovernmental Panel on Climate Change
http://www.ipcc.ch The Intergovernmental Panel on Climate Change is the leading body for the assessment of climate change, established by the United Nations Environment Programme (UNEP) and the World Meteorological Organization (WMO) to provide the world with a clear scientific view on the current state of climate change and its potential environmental and socio-economic consequences.