Great Lakes Water Levels Expected to be Below 2009, Future Drop Seen
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Is global climate change already affecting the Great Lakes region?
The Great Lakes are at, or slightly below, the levels they were in March 2009 although a drop of up to a foot may occur this year.
But a federal report on climate change predicts the lake levels could drop by as much as two feet in coming decades.
The carbon emissions that contribute to global warming in the Midwest are higher than the entire west or east coasts. according to the World Resources Institute (WRI), a center for policy research on global environmental and resource issues. The region is the seventh largest contributor worldwide.
Warming temperatures reduce ice cover and increase evaporation. Lake Huron and Lake Michigan are projected to have the greatest changes.
"Less winter ice and warmer temperatures in the summer could mean a decrease of one to two feet in Great Lake levels by the end of the century," said Melanie Fitzpatrick, a climate scientist with the WRI organization.
The series of reports, Confronting Climate Change in the U.S. Midwest, aims to explain the current effects and predict potential consequences of climate change on Midwest states. The reports cover Illinois, Iowa, Michigan, Wisconsin, Indiana, Minnesota, Missouri and Ohio.
Other projections of the report for the end of the century if climate change is unchecked:
-Each summer, Chicago would face 70 days with temperatures greater than 90 degrees, and at least two major heat waves.
-Spring and winter in Michigan would see a 25 percent increase in precipitation.
-All summers in Wisconsin would be hotter than in 1988, the state's hottest summer on record.
-Indiana, as well as several other states, would experience warmer winters. That extends the growing season by six weeks. It also allows pests more time to destroy crops.
-Snow days in Minnesota would decrease by a third.
-Cincinnati would face more than 85 days with temperatures greater than 90 degrees. Cleveland could see more than 60 days that are that warm.
Fitzpatrick cited manufacturing, power production and transportation as possible reasons for the high levels in the region.
The lakes experienced unusually low levels from 1997-2007, hitting near record lows in late 2007. This decline eased in 2008, and there was a general increase in levels from 2008-2009. In February 2010, an ice jam dropped levels in Lake St. Clair; levels have since rebounded with the removal of the jam.
As of March 2010, the lakes are at the level, or slightly below, where they were in March 2009.
An inter-agency U.S. government report has outlined region-by-region challenges from global climate change, and the Great Lakes region faces an especially complex array of challenges. Home to 20 percent of the world's fresh water supply, the Great Lakes - Superior, Huron, Michigan, Erie, Ontario - could see their levels drop by as much as two feet during the 21st century.
The government report, "Global Climate Change Impacts in the United States," was commissioned in 2007 during the Bush Administration and was released last year.
Produced by the U.S. Global Change Research Program, which was led by the National Oceanic and Atmospheric Administration, the report is the most comprehensive report to date on climate change impacts in the US, with the latest information on rising temperatures, heavy downpours, extreme weather, sea level changes and other results of climate change.
In its sections on the Midwest region, the report concluded that lower Great Lakes water levels would affect beaches, coastal ecosystems, fish populations, dredging requirements and shipping.
Observations show that warming of the climate is unequivocal. The global warming observed over the past 50 years is due primarily to human-induced emissions of heat-trapping gases. These emissions come mainly from the burning of fossil fuels (coal, oil, and gas), with important contributions from the clearing of forests, agricultural practices, and other activities.
Warming over this century is projected to be considerably greater than over the last century. The global average temperature since 1900 has risen by about 1.5ºF. By 2100, it is projected to rise another 2 to 11.5ºF.
The U.S. average temperature has risen by a comparable amount and is very likely to rise more than the global average over this century, with some variation from place to place. Several factors will determine future temperature increases. Increases at the lower end of this range are more likely if global heat-trapping gas emissions are cut substantially.
If emissions continue to rise at or near current rates, temperature increases are more likely to be near the upper end of the range. Volcanic eruptions or other natural variations could temporarily counteract some of the human-induced warming, slowing the rise in global temperature, but these effects would only last a few years.
Reducing emissions of carbon dioxide would lessen warming over this century and beyond. Sizable early cuts in emissions would significantly reduce the pace and the overall amount of climate change. Earlier cuts in emissions would have a greater effect in reducing climate change than comparable reductions made later.
In addition, reducing emissions of some shorter-lived heat-trapping gases, such as methane, and some types of particles, such as soot, would begin to reduce warming within weeks to decades.
Climate-related changes have already been observed globally and in the United States. These include increases in air and water temperatures, reduced frost days, increased frequency and intensity of heavy downpours, a rise in sea level, and reduced snow cover, glaciers, permafrost, and sea ice.
A longer ice-free period on lakes and rivers, lengthening of the growing season, and increased water vapor in the atmosphere have also been observed. Over the past 30 years, temperatures have risen faster in winter than in any other season, with average winter temperatures in the Midwest and northern Great Plains increasing more than 7ºF. Some of the changes have been faster than previous assessments had suggested.
These climate-related changes are expected to continue while new ones develop. Likely future changes for the United States and surrounding coastal waters include more intense hurricanes with related increases in wind, rain, and storm surges (but not necessarily an increase in the number of these storms that make landfall), as well as drier conditions in the Southwest and Caribbean. These changes will affect human health, water supply, agriculture, coastal areas, and many other aspects of society and the natural environment.
This report synthesizes information from a wide variety of scientific assessments (see page 7) and recently published research to summarize what is known about the observed and projected consequences of climate change on the United States. It combines analysis of impacts on various sectors. U.S. Global Change Research Program has identified 10 Global Climate Change Impacts in the United States such as energy, water, and transportation at the national level with an assessment of key impacts on specific regions of the United States. For example, sea-level rise will increase risks of erosion, storm surge damage, and flooding for coastal communities, especially in the Southeast and parts of Alaska.
Reduced snowpack and earlier snow melt will alter the timing and amount of water supplies, posing significant challenges for water resource management in the West.
Society and ecosystems can adjust to some climatic changes, but this takes time. The projected rapid rate and large amount of climate change over this century will challenge the ability of society and natural systems to adapt. For example, it is difficult and expensive to alter or replace infrastructure designed to last for decades (such as buildings, bridges, roads, airports, reservoirs, and ports) in response to continuous and/or abrupt climate change.
Impacts are expected to become increasingly severe for more people and places as the amount of warming increases. Rapid rates of warming would lead to particularly large impacts on natural ecosystems and the benefits they provide to humanity. Some of the impacts of climate change will be irreversible, such as species extinctions and coastal land lost to rising seas.
Unanticipated impacts of increasing carbon dioxide and climate change have already occurred and more are possible in the future. For example, it has recently been observed that the increase in atmospheric carbon dioxide concentration is causing an increase in ocean acidity. This reduces the ability of corals and other sea life to build shells and skeletons out of calcium carbonate.
Additional impacts in the future might stem from unforeseen changes in the climate system, such as major alterations in oceans, ice, or storms; and unexpected consequences of ecological changes, such as massive dislocations of species or pest outbreaks.
Unexpected social or economic changes, including major shifts in wealth, technology, or societal priorities would also affect our ability to respond to climate change. Both anticipated and unanticipated impacts become more challenging with increased warming.
Access the full report at http://environmentalism.suite101.com/article.cfm/study_says_climate_change_already_impacting_midw#ixzz0mQTBeqIW ###
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