A consensus Bali Climate Declaration, signed by more than 200 members of the international climate science community, says that the goal of a new climate treaty regime “must be to limit global warming to no more than 2º C above the pre-industrial temperature,” and lays out targets for achieving this goal. The signers of the Declaration include about 75 U.S. scientists, in both universities and government labs.

Our comment follows the list of signers.

This consensus document was prepared under the auspices of the Climate Change Research Centre at the University of New
South Wales in Sydney, Australia.

Bali Climate Declaration

The 2007 IPCC report, compiled by several hundred climate scientists, has unequivocally concluded that our climate is warming rapidly, and that we are now at least 90% certain that this is mostly due to human activities. The amount of carbon dioxide in our atmosphere now far exceeds the natural range of the past 650,000 years, and it is rising very quickly due to human activity. If this trend is not halted soon, many millions of people will be at risk from extreme events such as heat waves, drought, floods and storms, our coasts and cities will be threatened by rising sea levels, and many ecosystems, plants and animal species will be in serious danger of extinction.

The next round of focused negotiations for a new global climate treaty (within the 1992 UNFCCC process) needs to begin in December 2007 and be completed by 2009. The prime goal of this new regime must be to limit global warming to no more than 2 ºC above the pre-industrial temperature, a limit that has already been formally adopted by the European Union and a number of other countries.
Based on current scientific understanding, this requires that global greenhouse gas emissions need to be reduced by at least 50% below their 1990 levels by the year 2050. In the long run, greenhouse gas concentrations need to be stabilised at a level well below 450 ppm (parts per million; measured in CO2-equivalent concentration). In order to stay below 2 ºC, global emissions must peak and decline in the next 10 to 15 years, so there is no time to lose.

As scientists, we urge the negotiators to reach an agreement that takes these targets as a minimum requirement for a fair and effective global climate agreement.

The 2007 Bali Climate Declaration has been signed by the following scientists:

Name     

Title   

Country

Richard Allan  

Dr  

United Kingdom

Richard Anthes  

Dr  

USA

Waleed Abdalati  

Head, Cryospheric Sciences Branch  

USA

Becky Alexander  

Assistant Professor  

USA

Ian Allison  

Dr  

Australia

Caspar Ammann  

Research Scientist  

USA

Leif Anderson  

Professor  

Sweden

Jean-Claude Andre  

Dr  

France

Natalie Andronova  

Research Scientist  

USA

David Archer  

Professor  

USA

Mike Archer  

Professor. Dean of Science  

Australia

Vincenzo Artale  

Senior Research Scientist  

Italy

Paulo Artaxo  

Professor  

Brazil

Karen Assmann  

Dr  

Norway

Dorothee Bakker  

Dr  

United Kingdom

Edouard Bard  

Professor College de France  

France

Tim Barnett  

Research Marine Physicist  

USA

J. Ray Bates  

Professor  

Ireland

Richard Bellerby  

Dr  

Norway

Rasmus E. Benestad  

Dr  

Norway

Terje Berntsen  

Senior Scientist  

Norway

Nathan Bindoff  

Professor Physical Oceanography  

Australia

Robert Bindschadler  

Chief Scientist, Hydrospheric/Biospheric Laboratory  

USA

Roxana Bojariu  

Head, Climate Research Group  

Romania

Sandrine Bony  

Research Scientist  

France

Laurent Bopp  

Dr  

France

Alberto Borges  

Dr  

Belgium

Philippe Bousquet  

Assistant Professor  

France

Pascale Braconnot  

Dr  

France

Raymond S. Bradley  

Professor. Director. Climate System Research
Center  

USA

Guy Brasseur  

Senior Scientist  

USA

Francois-Marie Breon  

Professor  

France

Christopher Bretherton  

Director. Program on Climate Change  

USA

Victor Brovkin  

Dr  

Germany

Erik Buitenhuis  

Dr  

United Kingdom

Pep Canadell  

Executive Director Global Carbon Project  

Australia

Mark Cane  

Professor  

USA

Carlo Carraro  

Professor  

Italy

Anny Cazenave  

Senior Scientist  

France

Marie-Lise Chanin  

Director of Research Emeritus  

France

Sylvie Charbit  

Dr  

France

Robert J. Charlson  

Professor  

USA

John Church  

Chief Research Scientist  

Australia

Garry Clarke  

Emeritus Professor of Geophysics  

Canada

Martin Claussen  

Professor. Director. Max Planck Inst.  

Germany

William D. Collins  

Professor and Senior Scientist  

USA

Paul Crutzen  

Professor  

Germany/USA

Kurt M. Cuffey  

Professor  

USA

Valerie Daux  

Dr  

France

Anthony Del Genio  

Physical Scientist  

USA

Kenneth Denman  

Senior Scientist  

Canada

Robert E. Dickinson  

Professor  

USA

Paul Dirmeyer  

Research Scientist  

USA

Helge Drange  

Professor  

Norway

Kerry Emanuel  

Professor  

USA

Matthew England  

Professor and ARC Federation Fellow  

Australia

Ian Enting  

Professor  

Australia

Jean-Louis Fellous  

Earth observation satellite expert  

France

Jonathan Fink  

Director. Global Institute of
Sustainability  

USA

Andreas Fischlin  

Director Terrestrial Systems Ecology. ETH Zurich   

Switzerland

Jacqueline Flückiger  

Research Scientist  

Switzerland

Chris E. Forest  

Research Scientist  

USA

Piers Forster  

Reader in Climate Change Physics  

UK

Joos Fortunat  

Professor  

Switzerland

Roger Francey  

Senior Scientist  

Australia

Helen Amanda Fricker  

Associate Research Geophysicist  

USA

Pierre Friedlingstein  

Dr  

France

Andrew D. Friend  

Dr  

United Kingdom

Qiang Fu  

Professor  

USA

Andrey Ganopolski  

Scientist  

Germany

Catherine Gautier  

Professor  

USA

Alexander Gershunov  

Research Climatologist  

USA

Sarah Gille  

Associate Professor  

USA

Nathan Gillet  

Dr  

UK

Valerie Gros  

Dr  

France

Nicolas Gruber  

Professor  

Switzerland

Hoshin Gupta  

Professor  

USA

Kimio Hanawa  

Professor  

Japan

Bogi Hansen  

Professor  

Faroe Islands

Mohamed H.A. Hassan  

Professor  

Italy

Klaus Hasselmann  

Prof. Emeritus  

Germany

Gerald Haug  

Professor  

Switzerland

Didier Hauglustaine  

Directeur de Recherche CNRS  

France

A. D. J. Haymet  

Professor  

USA

Gabriele Hegerl  

Dr and Reader Geosciences  

UK,USA

Martin Heimann  

Professor. Director. Max-Planck-Inst.  

Germany

Christoph Heinze  

Professor in Chemical Oceanography  

Norway

Ann Henderson-Sellers  

Professor  

Australia

Jens Hesselbjerg Christensen  

Head of Climate Research Programme  

Denmark

Bruce Hewitson  

Professor  

South Africa

Kip Hodges  

Director. School of Earth & Space Exploration  

United States

Georg Hoffman  

Dr  

France

Marika Holland  

Scientist  

USA

David M Holland  

Professor  

USA

Elisabeth A. Holland  

Program Lead, Biogeosciences Program, NCAR  

USA

Greg Holland  

Senior Scientist Severe Weather Research and Applications  

USA

Lesley Hughes  

Professor  

Australia

James W. Hurrell  

Senior Scientist  

USA

Stan Jacobs  

Senior Research Scientist  

USA

Eystein Jansen  

Professor. Director  

Norway

Truls Johannessen  

Professor of Chemical Oceanography  

Norway

Ian Joughin  

Senior Engineer  

USA

Masa Kageyama  

Dr  

France

Robert Kandel  

Emeritus Senior Scientist  

France

Georg Kaser  

Professor  

Austria

Ralph Keeling  

Professor of Geochemistry  

USA

Robert M. Key  

Research Oceanographer  

United States

Jeffrey Kiehl  

Senior Scientist  

USA

Miko Kirschbaum  

Senior Scientist  

New Zealand

Christine Klaas  

Dr  

Germany

Albert Klein Tank  

Dr  

Netherlands

Reto Knutti  

Professor  

Switzerland

Rupa Kumar Kolli  

Dr  

India

René Laprise  

Professor. Director ESCER Centre   

Canada

Corinne Le Quere  

Professor  

United Kingdom

Herve Le Treut  

Director. Laboratoire de Meteorologie Dynamique  

France

Peter Lemke  

Professor  

Germany

Conway Leovy  

Professor Emeritus  

USA

Sydney Levitus  

Director. World Data Center for
Oceanography  

USA

Ulrike Lohmann  

Professor  

Switzerland

Diana Liverman  

Professor  

United Kingdom

Dan Lubin  

Research Physicist  

USA

Joachim Luther  

Professor  

Germany

Amanda H. Lynch  

Professor and ARC Federation Fellow  

Australia

Jose Antonio Marengo  

Senior Scientist  

Brazil

Jochem Marotzke  

Professor. Director. Max Planck Inst.  

Germany

Valerie Masson-Delmotte  

Dr  

France

Ben Matthews  

Dr  

Belgium

Cecilie Mauritzen  

Senior Scientist  

Norway

Bryant McAvaney  

Senior Principal Research Scientist  

Australia

James J. McCarthy  

Professor of Oceanography   

USA

Jeffrey J. McDonnell  

Professor and Richardson Chair in Watershed
Science  

USA

Trevor J. McDougall  

Dr  

Australia

Tony McMichael  

Professor  

Australia

Ben McNeil  

Queen Elizabeth II Research Fellow  

Australia

Nicolas Metzl  

Dr  

France

Elisabeth Michel  

Dr  

France

Guy Midgley  

Dr  

South Africa

Arthur J. Miller  

Research Oceanographer  

USA

Gunnar Myhre  

Senior Scientist  

Norway

Neville Nicholls  

Professor  

Australia

Richard D. Norris  

Professor and Curator, SIO Geological Collections  

USA

Daniel Olago  

Dr. Senior Lecturer University of Nairobi  

Kenya

Michael Oppenheimer  

Professor  

USA

Bette Otto-Bliesner  

Senior Scientist  

USA

Jonathon Overpeck  

Director Institute for the Study of Planet Earth  

USA

Didier Paillard  

Dr  

France

Wm. Richard Peltier  

University Professor of Physics  

Canada

Andy Pitman  

Professor  

Australia

Serge Planton  

Senior Scientist  

France

Gian-Kasper Plattner  

Dr  

Switzerland

Jan Polcher  

Directeur de Recherche du CNRS  

France

Michael J. Prather  

Fred Kavli Professor  

USA

Stefan Rahmstorf  

Professor of Physics of the Oceans  

Germany

Philip Rasch  

Senior Scientist  

USA

Michael Raupach  

Dr  

Australia

Chris Reason  

Professor. Oceanography  

South Africa

James Renwick  

Science Leader, Climate Variability & Change   

New Zealand

Ulf Riebesell  

Professor  

Germany

Stephen R. Rintoul  

Dr  

Australia

Johan Rockström  

Associate Professor  

Sweden

Terry L. Root  

University Faculty, Senior Fellow  

USA

Lynn M. Russell  

Professor of Atmospheric Chemistry  

USA

Toshiro Saino  

Professor  

Japan

Christoph Schär  

Professor in Atmospheric Sciences, ETH Zurich  

Switzerland

John Schellnhuber  

Professor  

Germany

Gavin Schmidt  

Research Scientist, NASA GISS  

USA

Stephen H. Schneider  

Professor  

USA

Birgit Schneider  

Dr  

France

Michael Schulz  

Senior Scientist  

France

Richard Seager  

Senior Research Scientist   

USA

Jeffrey P. Severinghaus  

Professor of Geosciences  

USA

Drew Shindell  

Senior Scientist and Lecturer  

USA

W James Shuttleworth  

Professor. Director NSF SAHRA
Center  

USA

Murugesu Sivapalan  

Professor  

USA

John P. Smol  

Professor  

Canada

Olga Solomina  

Dr  

Russia

Richard Somerville  

Professor  

USA

Will Steffen  

Professor  

Australia

Thomas Stocker  

Professor  

Switzerland

Kristof Sturm  

Associate Professor  

Sweden

John Sulston  

Dr  

United Kingdom

Didier Swingedouw  

Dr  

France

Lynne D. Talley  

Professor  

USA

Karl E. Taylor  

Dr  

USA

Fichefet Thierry  

Professor  

Belgium

Helmuth Thomas  

Associate Professor. Canada Reseach Chair  

Canada

Jerry Tjiputra  

Dr  

Indonesia

Kevin Trenberth  

Dr. Head, Climate Analysis Section  

USA

Peter A. Troch  

Professor  

USA

Carol Turley  

Dr  

United Kingdom

A.S Unnikrishnan  

Senior Scientist  

India

Francisco P. J. Valero  

Director Atmospheric Research Laboratory  

USA

Rob Van Dorland  

Dr  

The Netherlands

Ricardo Villalba  

Director IANIGLA  

Argentina

Martin Visbeck  

Professor  

Germany

Andrea Volbers  

Dr  

Norway

Thorsten Wagener  

Assistant Professor  

USA

John Wahr  

Professor  

USA

Warren M. Washington  

Senior Scientist  

USA

Bob Wasson  

Professor  

Australia

Andrew Watson  

Professor  

United Kingdom

Ian G. Watterson  

Dr  

Australia

Andrew Weaver  

Professor  

Canada

Peter J. Webster  

Professor  

USA

Ray F. Weiss  

Professor  

USA

James W.C. White  

Professor  

USA

Jürgen Willebrand  

Professor Emeritus  

Germany

Larry Winter  

Deputy Director NCAR  

USA

Carl Wunsch  

Professor of Physical Oceanography  

USA

Xubin Zeng  

Professor  

USA

Guang J. Zhang  

Research Meteorologist  

USA

The Declaration concludes: “As scientists, we urge the negotiators to reach an agreement that takes these targets as a minimum requirement for a fair and effective global climate agreement.”

Thus, the signers are acting as citizen-scientists — bringing their credentials and expertise as scientists to bear in speaking and acting as citizens to engage governments on a central problem of public policy, not solely as science educators but also as advocates.  We fully support this. We know that members of the climate science community are undertaking this essential responsibility with the utmost seriousness of purpose. Policymakers and their fellow citizens need to pay attention to what they are saying.