Stories tagged Great Lakes
From Eurekalert.org
Contact: Jonathan Patz
patz@wisc.edu
608-262-4775
University of Wisconsin-Madison
Waterborne disease risk upped in Great Lakes
MADISON — An anticipated increased incidence of climate-related extreme rainfall events in the Great Lakes region may raise the public health risk for the 40 million people who depend on the lakes for their drinking water, according to a new study.
In a report published today (Oct. 7, 2008) in the American Journal of Preventive Medicine, a team of Wisconsin researchers reports that a trend toward extreme weather such as the monsoon-like rainfall events that occurred in many parts of the region this past spring is likely to aggravate the risk for outbreaks of waterborne disease in the Great Lakes region.
"If weather extremes do intensify, as these findings suggest, our health will be at greater risk," according to Jonathan Patz, a University of Wisconsin School of Medicine and Public Health professor of population health and an expert on the health effects of climate change.
A primary threat to human health, says Patz, are the extreme precipitation events that overwhelm the combined urban storm water and sewage systems such as those in Milwaukee and Chicago, resulting in millions of gallons of raw sewage being diverted to Lake Michigan. Adding to the risk throughout the region, Patz notes, is the growing concentration of livestock operations where heavy rainfall can wash large amounts of animal waste into the rivers and streams that drain into the Great Lakes, the world's greatest concentration of fresh surface water.
"It's the perfect storm," notes Patz. "Deteriorating urban water infrastructure, intensified livestock operations, and extreme climate change-related weather events may well put water quality, and thereby our health, at risk."
Waterborne diseases caused by pathogenic bacteria, viruses and parasites are among the most common health risks of drinking water. In 1993, Milwaukee experienced an outbreak in city drinking water of the parasite Cryptosporidium that exposed more than 400,000 people and killed more than 50.
Patz, who is also affiliated with UW-Madison's Nelson Institute for Environmental Studies' Center for Sustainability and the Global Environment, conducted the study with Stephen Vavrus, a climatologist and director of the UW-Madison Center for Climatic Research, also part of the Nelson Institute.
Changes in regional weather patterns and, in particular, an increase in the number and intensity of severe rainfall events are predicted to accompany global warming. Climatologists have already cataloged a decades-long trend toward more tempestuous weather, says Vavrus.
"We have seen an uptick in the incidence of severe precipitation events in the last couple of years, but this has been a trend for decades," says Vavrus, noting an increased frequency of both major storms and total precipitation in the late 20th century. "And we are expecting climate (in the Great Lakes region) to change significantly in the future, so we'll very likely see an increase in these extreme precipitation events."
Climate change, scientists know, will prompt extremes of the hydrologic cycle, causing intensified precipitation as well as drought. Using the best available computer climate models, the Wisconsin researchers found that southern Wisconsin is likely to experience a 10 to 40 percent increase in the strength of extremely heavy precipitation events, leading to greater potential for flooding and the waterborne diseases that accompany the high discharge of sewage into Lake Michigan.
Previously, Patz led a U.S. Environmental Protection Agency-funded study linking outbreaks of waterborne disease in the U.S. to extreme rainfall. That study, published in 2001, showed that two-thirds of waterborne disease outbreaks between 1948 and 1994 were correlated with heavy rainfall.
The new study, say Patz and Vavrus, points to a need to strengthen pubic health infrastructure and improve aging urban drinking water and sewage systems, and to improve land use planning to reduce the amount of runoff that occurs in urban areas during major precipitation events.
"This is where climate policy, land use policy and public health come together," Patz argues.
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The new study, which was funded by the U.S. Environmental Protection Agency, was co-authored by Christopher Uejio of UW-Madison's Nelson Institute and Sandra McLellan of the University of Wisconsin-Milwaukee.
-- Terry Devitt, (608) 262-8282, trdevitt@wisc.edu
Tags : This seems to be a big week for the Great Lakes, especially their restoration and preservation. The Great Lakes Legacy Act is making its way through Congress; presidential candidate Barack Obama has promised to set up a five billion dollar trust fund for protection of the 5 inland seas (in the spirit of non-partisan fairness here’s the Republicans’ response); the new Omnifilm, Mysteries of the Great Lakes just opened and is playing here at the SMM Omnitheater; and a new debate has started regarding the long-held practice of swabbing debris from the decks of Great Lake freighters once they get out on the lakes.
Great Lakes from space: Photo by NASAThe five Great Lakes, Superior, Michigan, Huron, Erie, and Ontario contain something like 20 percent of the world’s fresh water, and are the source of drinking water for millions of Canadians and Americans who live around them. I grew up along the shores of Lake Superior (our hillside neighborhood in Duluth set on the prehistoric lake bottom of a larger Ice Age ancestor) so I’m partial to good old Gichigami and its siblings, and I’m really glad to see some serious attention is being paid to their clean-up and preservation.
Lake Superior Day: Swimmers enjoy the waters of Lake Superior in Duluth, Minnesota's Canal Park.
Courtesy Mark RyanHow do you celebrate one of the largest pools of freshwater on Earth? By participating in the annual Lake Superior Day, that’s how! This Sunday, July 20, is Lake Superior Day, a day of celebrations for the world’s largest and cleanest freshwater lake.
Towns and communities lining the shores of Superior in Michigan, Minnesota, and Wisconsin, and the Canadian province of Ontario are planning all sorts of events in tribute to the greatest of the Great Lakes.
Picnics, beach clean-ups, library displays, kite flying, concerts, hikes, an essay contest, and government proclamations are all part of the day’s celebration to bring attention to this huge body of water that holds 10 percent of Earth’s fresh water. Events are planned all around the lake. For example, games and activities promoting water conservation will take place in Red Rock, Ontario. A family picnic is scheduled at Silver Harbour in Thunder Bay, Canada. Afternoon events will take place on Barker’s Island Festival Park in the city of Superior, Wisconsin, and scientists and lake area experts will be on hand at the Lake Superior Maritime Visitor Center at Canal Park in Duluth with information about the lake’s natural history, regional culture, and invasive aquatic species.
The annual event takes place on the third Sunday of July, and is sponsored by the Lake Superior Binational Forum, the U.S. Environmental Protection Agency, and Environment Canada. So, if you're anywhere near Gichigami this coming Sunday, join in the festivities, or just go jump in the lake!
Since 2005, an ebola-like virus has been killing fish in the Great Lakes. A major die-off was recently reported near Milwaukee, affecting some 30 species. While the disease does not affect humans, it could devastate sport and commercial fishing in the region. Though the disease has not hit Lake Superior yet, it is starting to spread out from the Great Lakes region, thanks to infected fish swimming into rivers and streams.
Lake Superior: Photo by Mark RyanLake Superior is the greatest of the Great Lakes, and lately has become the subject of great concern. Superior’s water level has been dropping at an alarming rate in recent years, and is now at an all-time low. Lake Superior sets on the border of the United States and Canada, and people from both countries are trying to get answers. Some blame the drop in level on climate change, due to the decline of ice formation each winter on the lake and the subsequent increased evaporation. I covered this subject in an earlier posting that you can read about here. But others point to a chain reaction of water loss due to erosion and human activity farther down the Great Lakes System where the St. Clair River drains out of Lake Huron. Whatever the reasons, people on both sides of Superior are worried. The Canadian Broadcasting Corporation recently created a documentary titled Who Pulled the Plug on Lake Superior? which details the story. Watch it here.
MORE ABOUT SUPERIOR
Having grown up in Duluth, Minnesota on the western tip of Lake Superior, I continue to have a fascination with the great inland sea. The body of water is huge and powerful, and not to be taken lightly in inclement weather, when its mood can change in a matter of minutes. Waves during storms can reach up to 30 feet in height. The lake is the grave to more than 325 shipwrecks.
Here are some more quick facts about Lake Superior:
- Elevation above sea level: 600 feet (183 m)
- Maximum Length 350 miles (563 km)
- Maximum Breadth: 160 miles (257 km)
- Average Depth: 483 feet (147 m)
- Maximum Depth 1333 feet (406 m)
- Average Water Temperature: 40 degrees F.
- It’s the largest freshwater lake in the world by surface area (31,820 square feet (2956 square meters))
- It holds more than 2900 cubic miles of water (12,100 cubic km) which is enough to cover all of North and South America with a foot of water
- The Anishiabe Ojibwe Indians called the lake “Gichigami”, which means “Big Water”.
A statistic I’ve always found interesting is that 3% of the water on Earth is fresh water, and 10% of that fresh water is held in Lake Superior. The total water in the four other Great Lakes match Superior’s volume, and together they equal the volume of water contained in Russia’s Lake Baikal, the largest freshwater lake by volume in the world.
Evidently, I’m not alone in this fascination with Lake Superior. Two conferences about the body of water are taking place in the next few weeks. The first is “Making a Great Lake Superior” (October 29-31, 2007), which will bring together scientists, tribal and government officials to present current research, education programs, and management ideas relating to the lake.
The second conference is the “Gales of November 2007” (November 2-3, 2007). It celebrates the maritime history of the lake, and will present exhibitors and speakers on regional history, shipwrecks, diving, and other lake-related subjects. This will be their 20th annual get-together.
Both conferences are being held at the Duluth Entertainment and Convention Center, in Duluth Minnesota.
Lastly, just for the heck of it, here’s a short video titled TWELVE MOONS ON GICHIGAMI that compresses a year of Lake Superior images into less than seven minutes.
LINKS
More about Lake Superior
“Making a Great Lake Superior” Conference
“Gales of November 2007” Conference
Great Lakes from space: Photo by NASAGlobal warming, or more accurately climate change, is being blamed for lower water levels and rising temperatures in some of the Great Lakes according to a recent article at NewScientist.com.
Lake Superior from the North Shore: Photo by Mark RyanLake Superior, which contains 10% of the world’s fresh water, is showing levels that are down about an inch-and-a-half from last year, and more than eighteen inches below its long-term mean level. Temperatures on the lake’s surface water has risen 2.5 degrees Celsius since 1979.
Both changes are attributed to the lack of ice on Superior during the winter months. Without ice cover, sunlight energy doesn’t get reflected back into the atmosphere, but is instead absorbed by the water, heating it, and causing evaporation to increase. Jay Austin, a limnologist at the University of Minnesota Duluth's Large Lakes Observatory, says most evaporation on the massive lake has been taking place during the winter.
Lakes Michigan and Huron are also experiencing increased temperatures and lower levels. However, the two smaller lakes, Ontario and Erie, are showing above average levels due to increased rainfall in the region from such non-local events as hurricanes Katrina and Dennis.
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