WASHINGTON — The effects of climate change driven by human activity are spreading through the United States faster than has been predicted, increasingly threatening infrastructure, water supplies, crops and shorelines, according to a review of climate science and its effects by a federal advisory committee.
The draft Third National Climate Assessment, issued every four years, delivers a bracing picture of environmental changes and natural disasters that mounting scientific evidence indicates is fostered by climate change: heavier rains in the Northeast, Midwest and Plains states that have overwhelmed storm drains and led to flooding and erosion; sea level rise that has battered coastal communities; drought that has turned much of the West into a tinderbox.
“Climate change, once considered an issue for a distant future, has moved firmly into the present,” the report says. “Americans are noticing changes all around them. Summers are longer and hotter, and periods of extreme heat last longer than any living American has ever experienced. Winters are generally shorter and warmer.”
Written by 240 scientists, business leaders and other experts, the draft Climate Assessment arrives days after the National Oceanic and Atmospheric Administration issued its annual State of the Climate Report, which noted that 2012 was the hottest year on record. Together, the two major reports and a year of drought, wildfires, floods and freak storms have teed up for President Barack Obama the chance to take substantial steps on climate change, environmentalists said.
The report explicitly addresses the most controversial question in climate change, saying that consumption of fossil fuels by humans is the main driver of climate change.
“The findings in the report are a three-alarm fire,” said Rep. Henry A. Waxman, D-Calif. “Climate change is already causing widespread disruption across the nation. We are in deep trouble if we don’t act forcefully this year.”