Climate Change is Already Here, Going to Get Worse

Extreme weather, drought, heavy rainfall and increasing temperatures are a fact of life in many parts of the U.S. as a result of human-induced climate change, researchers report today in a new assessment. These and other changes will continue and likely increase in intensity into the future, the scientists found.

Researchers representing 13 U.S. government science agencies, major universities and research institutes produced the study, "Global Climate Change Impacts in the United States." Commissioned in 2007, it is the most comprehensive report to date on national climate change, offering the latest information on rising temperatures, heavy downpours, extreme weather, sea level changes and other results of climate change in the U.S.

The 190-page report is a product of the interagency U.S. Global Change Research Program, led by the National Oceanic and Atmospheric Administration. It is written in accessible language, intended to better inform members of the public and policymakers about the social, environmental and economic costs of climate change. It focuses on effects by region and details how the nation's transportation, agriculture, health, water and energy sectors will be affected in the future.

In a press conference today, University of Illinois Harry E. Preble Professor of Atmospheric Sciences Don Wuebbles, a contributor to the assessment, outlined the current and predicted effects of climate change in the Midwest U.S.

"We well recognize that the earth's climate varies naturally and has been warmer and cooler in the past," Wuebbles said. "But we also know that the climate changes we are experiencing today are largely the result of human activities."

Average temperatures have risen in the Midwest in recent decades, Wuebbles said, especially in winter. The growing season has been extended by one week. Heavy downpours are now twice as frequent as they were a century ago, he said, and the Midwest has experienced two, record-breaking floods in the past 15 years.

These trends are expected to continue into the future, Wuebbles said. Average annual temperatures are expected to increase by about two degrees Fahrenheit over the next few decades, and by as much as seven to 10 degrees by the end of the century, he said, with more warming projected for summer than winter.

Precipitation is expected to increase in the winter and spring, while summer precipitation will likely decline.

"More of the precipitation is likely to occur during heavier events," Wuebbles said.

From here.

Two researchers at the U.S. Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab), Evan Mills and Michael Wehner, contributed to the analysis of the effects of climate change on all regions of the United States, described in a major report released today by the multi-agency U.S. Global Change Research Program. For the southwest region of the United States, which includes California, the report forecasts a hotter, drier climate with significant effects on the environment, agriculture and health.

"Global Climate Change Impacts in the United States" covers such effects as changes in rainfall patterns, drought, wildfire, Atlantic hurricanes, and effects on food production, fish stocks and other wildlife, energy, agriculture, water supplies, and coastal communities.

"This is the most thorough and up-to-date review ever assembled of climate-change impacts observed to date as well as those anticipated in the future across the United States," says Evan Mills, one of the Berkeley Lab scientists who contributed to the report. While the report paints an ominous picture of potential impacts, "the good news is that the harshest impacts of future climate change can be avoided if the nation takes deliberate action soon. This can be done through a balanced mix of activities to reduce greenhouse-gas emissions and adaptation to the otherwise unavoidable impacts," says Mills.

The report addresses nine zones of the United States (Southwest, Northwest, Great Plains, Midwest, Southeast, Northeast, Alaska, U.S. islands, and coasts), and describes potential climate change effects in each. California is part of the southwest zone, as well as a coastal zone.

Wehner, who is a climate researcher in the Scientific Computing Group of Berkeley Lab's Computational Research Division, developed projections of future climate change for the report chapters covering global and national impacts of climate change. One of Wehner's research interests is extreme weather conditions resulting from climate change. His work is principally supported by the Climate Change Prediction Program in the DOE Office of Science's Office of Biological and Environmental Research.

The precipitation map is one of the projections developed by Wehner. It shows, among other things, a substantial reduction in springtime rains in California, and summertime rains in the Pacific Northwest.

"Even in areas where precipitation is projected to increase, higher temperatures will cause greater evaporation leading to a future where drought conditions are the normal state. In the southwest United States, water resource issues will become a major issue," says Wehner.

Another of Wehner's graphics shows past and future projections of the global mean surface air temperature, an indicator of the magnitude of the effects of global climate change. The three different trajectories after 2009 show low emissions, and two high emissions scenarios of how the temperature increase caused by greenhouse gas emissions could play out. The projections are based on the most sophisticated climate models available.

"These and similar projections reveal that actions taken today would take several decades to make any noticeable change in the rate of warming. This is one of the factors that makes climate change a difficult policy issue. There is no instant gratification," says Wehner.

From here.

Go Mike! GOOOO!

Ok, yes, I've worked with Mike on things. He's a damned smart man. I'll see if I can wrangle up copy of the report and scrape some comments and graphs from it for the blog. A bit busy though.