Yesterday, the United States Global Change Research Program (USGCRP) released the most thorough report ever written on the current and predicted future impacts of climate change in the U.S., including estimated regional impacts. The report, Global Climate Change Impacts in the United States, integrates the research of 13 federal agencies and numerous research institutions, summarizes impacts by sector (water, energy, transportation, agriculture, ecosystems, human health and society) and presents options for responding and adapting to climate change.
Myriad impacts are anticipated or are now occurring in the mid-Atlantic (note: the report groups Maryland and D.C. in the "Northeast" and Virginia in "Southeast"). Some severe weather events that have already affected the mid-Atlantic and are very likely to continue in the future include:
--Fewer cold days and nights;
--More frequent hot days and nights;
--More frequent heatwaves;
--More frequent and intense heavy downpours;
--More rainfall during heavy precipitation events;
--More severe flooding events; and
--More intense hurricanes (not necessarily more frequent).
Keep reading for more on the current and predicted regional and national impacts of climate change in the U.S.
The USGCRP report describes projections under both high- and low-emissions scenarios. Models show that higher emissions of greenhouse gases will lead to larger and more severe impacts. This is especially evident in temperature and precipitation projections.
For example, "A day so hot that it is currently experienced once every 20 years would occur every other year or more frequently by the end of the century under the higher emissions scenario," according to the report. The D.C. area currently averages around or more than 30 days per year that reach 90 degrees Fahrenheit or higher (as of 2002, the averages at National and Dulles were 37 and 29, respectively). Given a low-emissions scenario, this could increase to 60-75 days by the end of the century for our area; under a high-emissions scenario, it could increase to 75-90 or more.
Besides extreme weather, the D.C. area is also experiencing more gradual and less obvious changes that have just as much impact, such as increasing streamflow and rising sea levels. According to the report, "during the last century, sea level along the Mid-Atlantic coast rose 5-6 inches faster than the global average due to subsidence [the sinking of a part of the Earth's surface], and the Intergovernmental Panel on Climate Change estimates that the global average sea level will rise between 0.6 and 2 feet in the next century."
An increase of one degree Fahrenheit in the east coast's average annual temperature over the past century was also noted, along with the projection of a 2.5 to 4 degree Fahrenheit temperature increase in winter and 1.5 to 3.5 increase in summer in the Northeast. Continued warming can lead to a longer growing season and other impacts on agriculture, such as less suitable conditions for apples, blueberries and other crops to grow.
On a national scale, a northward shift in cold-season storm tracks has already been observed, as has a trend toward less snowfall and more winter rainfall. An observed trend in light precipitation decreasing and heavy precipitation increasing will likely become even more dramatic if emissions continue to remain high.
Other expected impacts of climate change include increased demand for electricity, changes in water resources, damage to transportation infrastructure, changes in species ranges and migrations, and increased health risks. Even air quality is not immune to warming: "For cities that now experience ozone pollution problems, the number of days that fail to meet federal air quality standards is projected to increase with rising temperatures if there are not additional controls on ozone-causing pollutants," the report says.
The report's national and regional projections are based on the globally focused Intergovernmental Panel on Climate Change (IPCC) 2007 assessment report. Along with the summary of impacts, the new report offers a number of suggestions for adaptating to climate change, including examples of successful initiatives.
USGCRP, formerly the U.S. Climate Change Science Program, is comprised of 13 federal departments and agencies and was mandated by Congress in 1990 to "coordinate federal research on changes in the global environment and their implications for society." It defines global change as "changes in the global environment (including alterations in climate, land productivity, oceans or other water resources, atmospheric chemistry, and ecological systems) that may alter the capacity of the Earth to sustain life."
In conjunction with the report's release yesterday, the USGCRP also launched a new website to highlight key findings, other publications and educational resources. The materials break down global change to national and regional levels in a way that is accessible to the stakeholders, decision-makers, media and the public, and include an educators toolkit on climate change, wildlife and wild lands.
For more information on the USGCRP and to view the report, visit www.globalchange.gov.