The Intergovernmental Panel on Climate Change: IPCC

http://www.ipcc.ch/

Over 800 scientists from around the world are currently working to develop IPCCs 5th Assessment Report.
Three working groups are planned
  1)  The Physical Science Basis 

  2) Impacts, Adaptation and Vulnerability 

  3)  Mitigation of Climate Change.

The Final Synthesis Report is scheduled to be released in the Fall of 2014.