WASHINGTON (Reuters) - The consequences of climate change are now hitting the United States on several fronts, including health, infrastructure, water supply, agriculture and especially more frequent severe weather, a congressionally mandated study has concluded.
A draft of the U.S. National Climate Assessment, released on Friday, said observable change to the climate in the past half-century "is due primarily to human activities, predominantly the burning of fossil fuel," and that no areas of the United States were immune to change.
"Corn producers in Iowa, oyster growers in Washington State, and maple syrup producers in Vermont have observed changes in their local climate that are outside of their experience," the report said.
Months after Superstorm Sandy hurtled into the U.S. East Coast, causing billions of dollars in damage, the report concluded that severe weather was the new normal.
"Certain types of weather events have become more frequent and/or intense, including heat waves, heavy downpours, and, in some regions, floods and droughts," the report said, days after scientists at the National Oceanic and Atmospheric Administration declared 2012 the hottest year ever in the United States.
Some environmentalists looked for the report to energize climate efforts by the White House or Congress, although many Republican lawmakers are wary of declaring a definitive link between human activity and evidence of a changing climate.
The U.S. Congress has been mostly silent on climate change since efforts to pass "cap-and-trade" legislation collapsed in the Senate in mid-2010.
The 1,146-page draft report is available at ncadac.globalchange.gov/. A three-month period for public comment will now ensue, as well as a review by the National Academies of Sciences, before the final version is produced.
The advisory committee behind the report was established by the U.S. Department of Commerce to integrate federal research on environmental change and its implications for society. It made two earlier assessments, in 2000 and 2009.
Thirteen departments and agencies, from the Agriculture Department to NASA, are part of the committee, which also includes academics, businesses, nonprofits and others.
The report noted that of an increase in average U.S. temperatures of about 1.5 degrees F (.83 degree C) since 1895, when reliable national record-keeping began, more than 80 percent had occurred in the past three decades.
With heat-trapping gases already in the atmosphere, temperatures could rise by a further 2 to 4 degrees F (1.1 to 2.2 degrees C) in most parts of the country over the next few decades, the report said.
Certain positive consequences of rising temperatures, such as a longer growing season, were said to be offset by more disruptive impacts, including:
- threats to human health from increased extreme weather events, wildfires and air pollution, as well as diseases spread by insects and through food and water;
- less reliable water supply, and the potential for water rights to become a hot-button legal issue;
- more vulnerable infrastructure due to sea-level rise, bigger storm surges, heavy downpours and extreme heat;
- warmer and more acidic oceans.
"This draft report sends a warning to all of us: we must act in a comprehensive fashion to reduce carbon pollution or expose our people and communities to continuing devastation from extreme weather events and their aftermath," Senator Barbara Boxer, a California Democrat who heads the Senate environment committee, said in a statement.
Some Democrats hope President Barack Obama will use his executive powers to clamp down further on some carbon-polluting industries. Obama has cited climate change as a priority since being re-elected in November.
Democrats could consider narrow legislation aimed at funding climate change mitigation, some environmentalists say. That might include making schools and community centers better able to withstand the extreme weather that is one expected consequence of a changing climate.
Reporting By Deborah Zabarenko; Additional reporting by Richard Cowan; Editing by Ros Krasny and Peter Cooney