Report finds climate change already impacting the United States

The report, “Global Climate Change Impacts in the United States,” compiles years of scientific research and takes into account new data not available during the preparation of previous large national and global assessments. Image sourced from U.S. Global Change Research Program

Climate change has been shown to already have a visible impact on the United States, says a new federal study assessing the current and anticipated domestic impacts of climate change.

The report, “Global Climate Change Impacts in the United States,” was produced by a consortium of experts from 13 US government science agencies and from several major universities and research institutes.
It compiles years of scientific research and takes into account new data not available during the preparation of previous large national and global assessments. With its production and review spanning Republican and Democratic administrations, it offers a valuable, objective, and scientific consensus on how climate change is affecting the United States.

The report confirms previous evidence that global temperature increases in the recent decades have been primarily human-induced. It incorporates the latest information on rising temperatures and sea levels, the increase in extreme weather events, and other climate-related phenomena.

The study finds that Americans are already being affected by climate change through extreme weather, drought, and wildfire trends, and details how the nation’s transportation, agriculture, health, water, and energy sectors will be affected in the future. The study also finds that the current trend in the emission of greenhouse gas pollution is significantly above the worst-case scenario that this and other reports have considered.

The report is not intended to direct policy makers to take any one approach over another to mitigate climate change or to adapt to it. But it emphasized that the choices made now will determine the severity of climate change impact in the future.

“Implementing sizable and sustained reductions in carbon dioxide emissions as soon as possible would significantly reduce the pace and the overall amount of climate change,” the report states, “and would be more effective than reductions of the same size initiated later.”

Among the main findings of the report are: that heat waves will become more frequent and intense; increased heavy downpours will lead to more flooding; reduced summer runoff and increasing water demands will create greater competition for water supplies; rising water temperatures and ocean acidification will threaten coral reefs and the marine ecosystems they support; insect infestations and wildfires have increased and will increase further; and local sea-level rise of three feet on top of storm surges will threaten homes and costal infrastructure.

The results are broken down in terms of region and economic sector and can provide a tool for policy makers and shareholders who will be affected by these trends such as farmers, local officials, public health officials, water resource officials, and business owners.

Responses to climate change fall into two categories. The first involves “mitigation” measures to limit climate change by reducing emissions of heat-trapping pollution or increasing their removal from the atmosphere. The second involves “adaptation” measures to improve our ability to cope with or avoid harmful impacts and take advantage of beneficial ones. “Both of these are necessary elements of an effective response strategy,” said Jerry Melillo of the Marine Biological Laboratory in Woods Hole, MA, who is a report co-chair.

A product of the interagency U.S. Global Change Research Program, the report was commissioned in 2007 and completed this spring. The report draws from a large body of scientific information, including the set of 21 Synthesis and Assessment reports from the U.S. Global Change Research Program. The government agencies affiliated with the program include the Departments of Agriculture, Commerce, Defense, Energy, Health and Human Services, Interior, State, and Transportation; the Environmental Protection Agency; NASA; National Science Foundation; the Smithsonian Institution; and the United States Agency for International Development.

The report is available for download online: http://www.globalchange.gov/usimpacts


-  Katrice R. Jalbuena

Sources:

¹ http://www.globalchange.gov/images/cir/pdf/Climate-Impacts-PR_june-6-2009.pdf
² http://www.globalchange.gov/