IPCC report says humans almost certainly cause global warming
By Darryl Fears, Updated: Friday, September 27, 4:58 PM
A panel of the world’s leading climate scientists strongly asserted Friday that “it is extremely likely that human influence has been the dominant cause” of global warming since 1950 and warned of more rapid ice melt and rising seas if governments do not aggressively act to reduce the pace of greenhouse gas emissions.
At a meeting in Stockholm, where the panel released its latest assessment of climate change, the scientists for the first time established a budget for the amount of carbon that can be released into the atmosphere. Even if that target is reached, carbon emissions will have a harmful impact on the environment well into the future.
“As the ocean warms, and glaciers and ice sheets reduce, global mean sea level will continue to rise but at a faster rate than we have experienced over the past 40 years,” said Qin Dahe, a Chinese scientist who co-chaired the working group that produced the first of the report’s three segments, a summary for government policymakers.
“As a result of our past, present and expected future emissions of [carbon dioxide], we are committed to climate change, and effects will persist for many centuries even if emissions . . . stop,” said Thomas Stocker, a German scientist who served as the other co-chair of the working group.
The 2,000-page report of the Intergovernmental Panel on Climate Change, appointed by the United Nations, will not be available until Monday, following a weekend of editing and corrections. But a summary highlighting 20 findings was provided early Friday.
Some key findings were that the planet is warming at an accelerated pace without any doubt, that humans are causing it with 95 percent certainty and that the past three decades have been the hottest since the start of the Industrial Revolution in 1850.
Carbon concentrations in the atmosphere have increased 40 percent since then and carbon, methane and nitrous oxide are at levels unprecedented in at least 800,000 years.
Greenland and Antarctic ice sheets have steadily lost mass over two decades, and glaciers are shrinking worldwide. Sea-level rise could reach three feet by 2100.
The panel expressed high confidence in its findings because climate models that help scientists observe surface temperature patterns have improved in the past six years, since its previous climate assessment. The current assessment is the IPCC’s fifth since 1990.
Scientists arrived at their conclusions by drawing on more than 9,000 publications. They considered more than 54,000 comments from about 1,050 people in 52 nations.
Yet the summary did little to dissuade a small but forceful chorus of scholars who deny that humans cause significant global warming or that the earth is suffering from warming impacts.http://www.washingtonpost.com/national/health-science/ipcc-says-humans-cause-global-warming/2013/09/27/aae32880-275d-11e3-b3e9-d97fb087acd6_story.html