AAAS President: IPCC Report Underscores Need for Strong Action on Climate

John Holdren

A new report from the Intergovernmental Panel on Climate Change (IPCC) "powerfully underscores" the need for a massive effort to slow global climate disruption, says AAAS President John P. Holdren.

On 2 February, the IPCC, an international group of scientists charged with reviewing the evidence on global climate change, issued "Climate Change 2007: The Physical Science Basis," a summary for policymakers. It was written by Working Group I of the IPCC as part of the panel's Fourth Assessment Report. The summary describes progress in understanding the human and natural drivers of climate change.

Holdren, president of the American Association for the Advancement of Science (AAAS), who also serves as director of the Woods Hole Research Center and Teresa and John Heinz Professor of Environmental Policy at Harvard University, released the following statement regarding the IPCC report:

"The new report powerfully underscores the need for a massive effort to slow the pace of global climatic disruption before intolerable consequences become inevitable. The report is far clearer and less equivocal in its description of how Earth's climate is changing—and in attributing the bulk of these changes to human activities—than the last IPCC report in 2001. That was to be expected, because since 2001 there has been a torrent of new scientific evidence on the magnitude, human origins, and growing impacts of the climatic changes that are underway. In overwhelming proportions, this evidence has been in the direction of showing faster change, more danger, and greater confidence about the dominant role of carbon dioxide from fossil-fuel burning and tropical deforestation in causing the changes that are being observed.

"A few climate-change 'skeptics' have tried to seize on pre-release accounts of the report's treatment of sea-level rise to assert that the IPCC's new portrayal is less pessimistic than the previous one. This is an obvious distortion. The report is very clear that the scientific basis for alarm about the pace and dangers of climate change has grown enormously since 2001. It states plainly that the observed pace of sea-level rise has been increasing, along with the pace of change in many other indicators of climate-linked danger. The report also makes clear that, while the processes that could further accelerate sea-level rise in a warming world are not fully understood and in some respects are controversial, the possibility of truly devastating increases in sea level is real."

The Intergovernmental Panel on Climate Change was established by the World Meteorological Organization and the United Nations Environment Programme in 1998 to assess scientific, technical, and socio- economic information relevant for the understanding of climate change, its potential impacts, and options for adaptation and mitigation. Its work engages the efforts of thousands of the world's leading analysts of every aspect of global climate change.

Susan Solomon, chair of the IPCC's Working Group I, will discuss the group's key physical-science findings during the 2007 AAAS Annual Meeting. Her public lecture will take place at 8:00 a.m. Monday, 19 February, in the Hilton San Francisco, Continental 4-6. To register for the AAAS Annual Meeting, log onto http://www.aaasmeeting.org.

Also during the AAAS Annual Meeting, Holdren will deliver a public Presidential Address Thursday, 15 February, at 6:30 p.m., in the Hilton, Continental 4-6. The theme of the 2007 meeting, "Science and Technology for Sustainable Well-Being," will focus on interactions among disciplines and in the influence of science and technology on the human condition. An array of climate-change events are planned, including a free public town hall meeting for teachers, students, and other communicators and learners on Sunday, 18 February, from 1:15 p.m. until 5:30 p.m. in the Hilton, Continental 4-6. For details, log onto http://www.aaas.org/climate

2 February 2007