Climate change is already reshaping the United States, according to a new federal report that predicts global warming could have serious consequences for how Americans live and work.
Hotter temperatures, an increase in heavy downpours, and rising sea levels are among the effects of "unequivocal" warming, concludes the report by the U.S. Global Change Research Program. Winters are now shorter and warmer than they were 30 years ago, with the largest temperature rise -- more than 7 degrees Fahrenheit -- observed in the Midwest and northern Great Plains.
The changes are already affecting human health, agriculture, coastal areas, transportation and water supplies. And climate change will intensify over the next century even with significant action to limit greenhouse gas emissions from human activities.
"The projected rapid rate and large amount of climate change over this century will challenge the ability of society and natural systems to adapt," warns the report, released yesterday in Washington by White House Office of Science and Technology Policy Director John Holdren and other top Obama administration officials.
The 196-page document -- the first major climate report from the Obama administration -- was also submitted to Congress, under a 1990 law that requires the White House to produce regular status updates on climate change in the United States. The Bush administration released a first draft of the report last year, after environmental groups successfully sued the government in federal district court.
The new report is based on published research, including a series of 21 reports on climate change produced by the Bush administration.
Forests shift, crops suffer, diseases move north
Released as House Democrats plan their floor strategy for major climate legislation, the analysis says that reducing carbon dioxide emissions will lessen warming during this century and beyond.
Earlier cuts will be more effective than comparable later cuts, the document adds. Without efforts to limit emissions, the United States could warm 7 to 11 degrees Fahrenheit by the end of the century. Cutting emissions could hold that increase to just 4 to 6.5 degrees Fahrenheit.
The report also breaks down likely effects of climate change by region and economic sector. Among its conclusions:
- Forest growth is likely to increase in much of the East but decrease in much of the West as water becomes scarcer.
- Heat-related deaths are likely to increase as the number of days when the mercury reaches 100 degrees Fahrenheit or higher grows. Without a reduction in greenhouse gas emissions, the report says, heat-related deaths in Chicago will rise tenfold by the end of the century.
- Sea level rise will continue, increasing the likelihood of temporary and permanent flooding of airports, roads, rail lines and tunnels. About 2,400 miles of roadways and 250 miles of freight rail lines could be inundated along the Gulf Coast over the next 50 to 100 years. The region is home to seven of the country's 10 largest ports.
- Crop production will suffer as carbon dioxide emissions rise, after an initial increase in growth. Warmer winter temperatures will help insects and plant diseases spread.
- A continuing trend of warmer night temperatures in the Northeast could shift maple syrup production from the United States to Canada.
'It affects the things people care about' -- Lubchenco
"What we've shown in this assessment is that we do need to act sooner rather than later," said Donald Wuebbles, an author of the report and an atmospheric scientist at the University of Illinois. "We want to avoid the worst of the kind of changes that we looked at."
National Oceanic and Atmospheric Administration chief Jane Lubchenco called the new report "a game-changer."
"I think much of the foot-dragging in addressing climate change is reflective of the perception that climate change is way down the road in the future, and it only affects remote parts of the planet," she said. "This report demonstrates that climate change is happening now, in our own backyards, and it affects the things that people care about. The dialogue is changing."
But she and other Obama administration officials who briefed reporters shied away from weighing in on climate proposals now before Congress. That includes the climate bill from House Energy and Commerce Chairman Henry Waxman (D-Calif.) and Rep. Ed Markey (D-Mass.).
"This is telling us with persuasiveness why we need to act sooner rather than later, and why action needs to include measures to reduce heat-trapping emissions and measures to adapt to unavoidable changes," said Holdren. "One has to hope it will influence how people think about particular legislative proposals."
Environmental groups hailed the new report, and a leader of one group said the analysis could help efforts to pass the Waxman-Markey bill.
"The timing is important," said World Wildlife Fund CEO Carter Roberts. "Right now, Congress is considering climate legislation and energy legislation. This report makes it pretty clear to constituents of every congressman and senator that we will see changes in the natural world and parts of the United States, and they will have consequences for our economy, our lifestyles and the places that we live."