The Honorable Barack Obama
President of the United States
The White House
1600 Pennsylvania Avenue, N.W.
Washington, D.C. 20050

August 3, 2011

President Obama:

We are researchers at work on the science of climate change and allied fields. We are writing to add our voices to the indigenous leaders, religious leaders, and environmentalists calling on you to block the proposed Keystone XL Pipeline from Canada’s tar sands.

The tar sands are a huge pool of carbon, but one that does not make sense to exploit.  It takes a lot of energy to extract and refine this resource into useable fuel, and the mining is environmentally destructive.  Adding this on top of conventional fossil fuels will leave our children and grandchildren a climate system with consequences that are out of their control.  It makes no sense to build a pipeline system that would practically guarantee extensive exploitation of this resource.

When other huge oil fields or coal mines were opened in the past, we knew much less about the damage that the carbon they contained would do to the Earth’s climate system and to its oceans. Now that we do know, it’s imperative that we move quickly to alternate forms of energy—and that we leave the tar sands in the ground. We hope those so inclined will join protests scheduled for August and described at tarsandsaction.org.

If the pipeline is to be built, you as president have to declare that it is “in the national interest.” As scientists, speaking for ourselves and not for any of our institutions, we can say categorically that it’s not only not in the national interest, it’s also not in the planet’s best interest.

Sincerely,

James Hansen
The Earth Institute, Columbia University

John Abraham
Associate Professor, School of Engineering
University of St. Thomas

Dean Abrahamson
Professor Emeritus Energy & Environment Policy
University of Minnesota

David Archer
Professor, Geophysical Sciences Department
The University of Chicago

Jason Box
Associate Professor, Department of Geography
Atmospheric Sciences Program
Researcher at Byrd Polar Research Center
The Ohio State University

Ken Caldeira
Senior Scientist
Department of Global Ecology
Carnegie Institution

Peter Gleick
President and Co-founder
Pacific Institute for Studies in Development, Environment, and Security

Richard A. Houghton
Senior Scientist
Woods Hole Research Center

Robert W. Howarth
David R. Atkinson Professor of Ecology & Environmental Biology
Cornell University

Ralph Keeling
Director, Scripps CO₂ Program
Scripps Institution of Oceanography

Donald Kennedy
President Emeritus and Bing Professor of Environmental Sciences, Emeritus
Institute for International Studies
Stanford University

Michael MacCracken
Chief Scientist for Climate Change Programs
Climate Institute

Michael E. Mann
Professor of Meteorology
Director, Earth System Science Center
The Pennsylvania State University

James McCarthy
Alexander Agassiz Professor of Biological Oceanography
Harvard University

Michael Oppenheimer
Albert G. Milbank Professor of Geosciences and International Affairs
Woodrow Wilson School and Department of Geosciences
Princeton University

Raymond T. Pierrehumbert
Louis Block Professor in the Geophysical Sciences
The University of Chicago

Steve Running
Professor of Ecology, Director of Numerical Terradynamics Simulation Group
Department of Ecosystem and Conservation Sciences
College of Forestry and Conservation, University of Montana

Richard Somerville
Distinguished Professor Emeritus and Research Professor
Scripps Institution of Oceanography

Ray J. Weymann
Director Emeritus, Carnegie Observatories
Member, National Academy of Sciences

George M. Woodwell
Founder, Director Emeritus, and Senior Scientist
Woods Hole Research Center