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Climate Science Symposium Reflects on Early Warnings, Today’s Perils

Five decades after the first climate change warning to an American president, the signs are apparent. Global temperatures have increased, extreme weather events are more common, and species are fleeing their habitats.

Climate Science, 50 Years Later, the 29 October symposium at the Carnegie Institute of Science in Washington, D.C., assembled more than a dozen prominent scientists who recounted the damages caused by climate change, reflected on the past, and considered how best to respond to an increasingly challenging future.

"The climate is changing at a pace and in a pattern that is not explainable by natural influences," said John P. Holdren, assistant to the president for science and technology and director of the White House Office of Science and Technology Policy. "We know that with global temperature about 0.9 degrees Celsius above pre-industrial, these changes are already causing significant harm to life." Holdren is a former AAAS president.

J. Marshall Shepherd of the University of Georgia discussed the challenges climate scientists face in communicating with the public. | Tracey Salazar

The event commemorates the 5 November 1965 President's Council of Advisors on Science and Technology (PCAST) report to President Lyndon B. Johnson, which warned that the accumulation of atmospheric carbon dioxide from the burning of fossil fuels would "almost certainly cause significant changes" to the environment. The symposium also represents a continuation of the AAAS What We Know climate change communications project, launched last year.

"We've known just about everything we need to know to do something about this issue for a very long time," said Katharine Hayhoe, director of the Texas Tech University Climate Science Center. "We knew that burning fossil fuels produces carbon. We knew that carbon was building up in the atmosphere and in the ocean. We knew that it was causing the temperature of the planet to heat. And we knew that there was one simple but terribly difficult solution — to stop."

AAAS organized the symposium in collaboration with the Carnegie Institution for Science, with support from the American Meteorological Society and the Linden Trust for Conservation.

"It's remarkable to think that that long ago the science was already pointing in a direction that we had to pay attention to atmospheric changes because they'd be so powerful that they would affect the climate," said Carnegie Science President Matthew Scott in a video address to the symposium. "Governments all over the world are looking to scientists for guidance."

The symposium speakers included more than a dozen prominent scientists who study the impacts of and possible adaptations to global climate change. | Tracey Salazar

A team of scientists demonstrated another tangible effect of climate change with a new study published Thursday in Science. In a news briefing, researchers from the Gulf of Maine Research Institute and Stony Brook University warned that rapidly warming waters in the Gulf of Maine have contributed to the collapse of cod stocks — despite cutbacks in fishing beginning in 2010.

"The vast majority of climate scientists agree that climate change is underway. It's real, it's [caused by] us, it's costly in lives and dollars and it can be addressed," said Rush D. Holt, CEO of AAAS and executive publisher of the Science family of journals. "Many individuals including AAAS have been paying attention to this issue for a long time."

About 97% of scientists agree that climate change is occurring, according to the AAAS What We Know report. But there's a gap between the scientific community and the public — about half of Americans said they do not believe humans are mostly responsible for climate change, according to a 2014 AAAS Pew Research survey.

That presents a challenge for scientists who are competing with that gap in understanding between the public, the scientific community, and lawmakers.

Following the symposium, AAAS organized a Capitol Hill briefing in conjunction with Sen. Ed Markey (D-Mass.) in the U.S. Capitol Senate Visitors Center. Science Editor-in-Chief Marcia McNutt moderated the Hill event, which included climate symposium speakers J. Marshall Shepherd of the University of Georgia and Chris Field of the Carnegie Institution and Stanford University.

A free webstream of the event is available at


Gavin Stern

Director of News and Information

Carla Schaffer