The report – which is full of figures, charts and other research-generated graphics – includes 3,096 footnotes referring to other mostly peer-reviewed research. It was written by more than 250 scientists and government officials, starting in 2012. A draft was released in January 2013, but this version has been reviewed by more scientists, including twice by the National Academy of Sciences which called it “reasonable,” and “a valuable resource.”
Environmental groups praised the report. “If we don’t slam the brakes on the carbon pollution driving climate change, we’re dooming ourselves and our children to more intense heat waves, destructive floods and storms and surging sea levels,” said Frances Beinecke, president of the Natural Resources Defense Council.
Scientists and the White House called it the most detailed and U.S.-focused scientific report on global warming.
The report looks at regional and state-level effects of global warming, compared with recent reports from the United Nations that lumped all of North America together.
“All Americans will find things that matter to them in this report,” said scientist Jerry Melillo of the Marine Biological Laboratory, who chaired the science committee that wrote it. “For decades we’ve been collecting the dots about climate change; now we’re connecting those dots.”
In a White House conference call with reporters, National Climatic Data Center Director Tom Karl said his two biggest concerns were flooding from sea level rise on the U.S. coastlines – especially for the low-lying cities of Miami, Norfolk, Virginia, and Portsmouth, New Hampshire – and drought, heat waves and prolonged fire seasons in the Southwest.
Even though the nation’s average temperature has risen by between 1.3 and 1.9 degrees since record keeping began in 1895, it’s in the big, wild weather where the average person feels climate change the most, said co-author Katharine Hayhoe, a Texas Tech University climate scientist. Extreme weather hits us in the pocketbooks and can be seen with our own eyes, she said.
The report says the intensity, frequency and duration of the strongest Atlantic hurricanes have increased since the early 1980s, but it is still uncertain how much of that is from man-made warming. Winter storms have increased in frequency and intensity and have shifted northward since the 1950s, it says. Also, heavy downpours are increasing – by 71 percent in the Northeast. Heat waves, such as those in Texas in 2011 and the Midwest in 2012, are projected to intensify nationwide. Droughts in the Southwest are expected to get stronger. Sea level has risen 8 inches since 1880 and is projected to rise between 1 foot and 4 feet by 2100.
Climate data center chief Karl highlighted the increase in downpours. He said last week’s drenching, when Pensacola, Florida, got up to two feet of rain in one storm and parts of the East had three inches in one day, is what he’s talking about.
The report says “climate change threatens human health and well-being in many ways.” Those include smoke-filled air from wildfires, smoggy air from pollution, and more diseases from tainted food, water, mosquitoes and ticks. And ragweed pollen season has lengthened.
Flooding alone may cost $325 billion by the year 2100 in one of the worst-case scenarios, with $130 billion of that in Florida, the report says. Already the droughts and heat waves of 2011 and 2012 have added about $10 billion to farm costs, the report says.