Climate change impacts to the Great Lakes

Climate change is hurting the Great Lakes region and without action to curb heat-trapping emissions, summer average temperatures in the region may increase by 14 degrees Fahrenheit within the lifetime of today's kindergartner. Unchecked global warming could also significantly lower lake levels, lead to droughts and deplete oxygen in water, creating more dead-zones where aquatic life can't survive. Higher temperatures also mean more invasive species for a region already rife with them. Nonnative carp, for instance, would be able to move into warmer water.

“The most expensive thing we can do about global warming is nothing,” says Dr. Barbara Ekwurzel, Climate Scientist from the Union of Concerned Scientists.  “The region needs to adapt to the changes coming, and take action to avoid the worst consequences of global warming.”

To adapt to looming changes of global warming, the region and the country need to aggressively take actions such as conserving water, reducing sprawl, and identifying ways to modify industrial practices. To avoid the worst consequences of global warming, the region and the country need to step up clean energy production and become more energy efficient. The Great Lakes region - already home to large manufacturing industries - could become a hub in a new clean energy economy.

Commercial shipping challenged by reduced water depths due to climate change

The lower water levels due to global climate change will reduce water depths and limit cargo vessel loads in the Great Lakes. Lake vessels are built and operated to take advantage of available water depths, often operating with minimal underkeel clearances. Ocean going vessels often have to function in the Great Lakes and St. Lawrence Seaway at less then their maximum cargo capacity. Reductions in water depths will force vessels to operate with reduced loads, thus increasing the number of trips and the cost of moving cargo. 

Research commissioned by Environment Canada and the Transportation Research Board of the National Academy of Sciences examined the impacts of global climate change on domestic and international shipping in the Great Lakes and St. Lawrence River system. The costs for a year's shipping in the Great Lakes and St. Lawrence River were estimated under conditions of no climate change impacts and under several climate change scenarios. A paper has been published in the Canadian Water Resources Journal.

"Depending on the climate change scenario, the increased costs to commercial shipping due to lower water depths vary from approximately 5% to over 29%,"said Dr. Frank Millerd, professor emeritus of economics from Wilfrid Laurier University in Waterloo, Ontario. "The decrease in water depths is likely the greatest potential impact of climate change that is facing freight transportation in the Great Lakes and St. Lawrence River."

The studies also determined that for those years with naturally occurring low water levels the impacts are up to and additional 12% higher for even the most moderate climate change scenario.

Some adaptation measures are possible, such as modifications to vessel operations and vessel replacement. "Addressing chronic low water levels will be a continuing challenge for the industry," said Dr. Millerd. 

Invasive species transported to the Great Lakes via international ballast

Zebra mussels truly changed the ecosystem and the economy in ways not seen since the sea lamprey invaded the upper lakes in the 1920s.

Zebra mussels are particularly insidious in that they undermine the very foundation of the Great Lakes’ food web.  Being filer feeders, zebra mussels rob fish and other organisms of the food they need.  They offer nothing in return; they provide no value as a prey organism and throw the natural ecosystem out of balance.  Zebra mussels are implicated in the alarming disappearance of Diporeia, a key native zooplankter that is vital to the diet of many native fish species.  Zebra mussels, when they interact with round gobies, another exotic pest, help produce the conditions that move botulism up the food web, killing Great Lakes fish and birds.

“Overall, zebra mussels have cost the fishery, the economy, and the people of the region dearly.  It is time to learn from the hard lessons zebra mussels have taught us,” says Marc Gaden, Communications Officer for the Great Lakes Fishery Commission. “We must manage the ballast from oceangoing vessels; ballast that has permanently littered our lakes with trash species like zebra mussels.”

Ballast mediated invaders spread throughout the St. Lawrence and Rideau Rivers

Prior to 1993, the Rideau River was clean of zebra mussels and had a rich diversity and abundance of native unionid clams. But, it would not take long for the invasive zebra mussel to take hold and spread throughout the river.

For six years starting in 1993, André Martel and his team at the Canadian Museum of Nature tracked how the zebra mussel virtually destroyed the native clam population, building huge colonies on the shells of the native clams (sometimes also referred as native mussels), effectively starving them.

In only four years the native clam population had disappeared over vast areas of the river and the spread of the zebra mussel was comparable to, if not greater than, the highest spread of the mussel in the Great Lakes. In some downstream areas, densities of zebra mussels exceeded 150,000 individuals per square metre.

 "We knew that the ecological impact of the zebra mussel was severe in the Great Lakes region. Here in the Rideau River, we found the first zebra mussels soon after their discovery in Lake St. Clair," said Dr. Martel.
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They were on a large steel ship that had made its way up the Rideau Canal to Ottawa after having spent some time sailing in the zebra mussel-ladden Lake Erie."

André Martel and his fellow researchers and volunteer divers were the first to employ SCUBA-diving techniques to quantitatively investigate and document the long-term impacts of the zebra mussel on a small river ecosystem.

"Ironically, the Rideau River and Rideau Canal would become one of Canada’s Heritage Rivers and a UNESCO World Heritage Site. It is unfortunate that the Rideau River-Rideau Canal system had to lose much of its rich native mussel populations before reaching this status simply because of our failure to properly control or prevent the transport of invasive mollusks like the zebra mussels in transoceanic cargo ships bound for Canada."

Boaters and Anglers battle spread of invaders across inland Ontario

Following the discovery of the zebra mussel in Lake St. Clair in 1988, it quickly spread to all the Great Lakes and connected waterways such as the Trent Severn Waterway and Rideau Canal. Using these recreational corridors, in less than a decade zebra mussels had gained access to many of the major watersheds of southern Ontario.

Recognizing the devastating impacts zebra mussels and other aquatic invaders could have on Ontario's 250,000 inland lakes, the Ontario Federation of Anglers and Hunters in partnership with the Ontario Ministry of Natural Resources created the Invading Species Awareness Program.

"Since 1992, we have educated hundreds of thousands of boaters and anglers about this issue; posted signs at over 3000 boat launches, and successfully engaged public participation in measures to stop overland spread from recreational watercraft said Francine MacDonald Invasive Species Biologist for the Ontario Federation of Anglers and Hunters.  "We are also actively involving hundreds of community groups to participate in "Invading Species Watch" initiatives to annually monitor lakes and waterways for zebra mussels and other invaders".

Similar efforts have also been initiated in neighbouring provinces such as Manitoba and Quebec to stop the further spread of zebra mussels across the country.

However MacDonald added "Despite all of these significant outreach and prevention efforts, we are fighting an uphill battle, if action is not taken immediately to stop new introductions to the Great Lakes and Canada's coastal waters from ship ballast and other vectors."

Historic practice of dry cargo dumping under scrutiny

Currently, ships on the Great Lakes dump cargo waste into the water—even though international and domestic laws prohibit so-called “cargo sweeping” or “dry cargo discharge” in any of the internal waterways. The U.S. Coast Guard has allowed the practice for at least 70 years, resulting in the deposition of about 550 tons of coal, limestone, iron ore and taconite into Great Lakes waters annually.
 
Conservation groups on both sides of the border want dumping in the Great Lakes to stop and support enforcement of federal and international laws to end to the practice.

“For Great Lakes restoration to succeed, we can’t use the lakes as a dumping ground,” says Lyman Welch, Water Quality Program Manager for the Alliance for the Great Lakes. “Everyone needs to do their part. Every change made to improve the health of the Great Lakes will help turn the tide towards a restored ecosystem.”
 
Many of the cargo residues -- especially iron ore and taconite -- contain mercury and other toxic metals that can harm wildlife, as well as people who eat fish potentially contaminated by the metals. The practice can also help invasive species such as the zebra and quagga mussels to expand their territories. The environmental impacts of cargo dumping are not adequately understood, and the groups maintain that the health of the Great Lakes is at a precarious tipping point due to a combination of stresses- from habitat alteration to toxic pollution, invasive species and sewage overflows. Without across-the-board improvements the groups warn of massive and potentially irreversible damages to the Great Lakes ecosystem.

“Operating commercial ships on the drinking reservoir of tens of millions is a privilege. We need a commitment to continued improvement by the shipping industry. The expansion of existing best practices and phasing in of new regulations should start now,” says Mark Mattson, President and Waterkeeper for the Lake Ontario Waterkeeper.

Ice breaking on the St. Lawrence River

“Residents here in the Thousand Islands have been fighting the Seaway’s attempts to lengthen the shipping season for more than thirty years, and yet the season gets longer and longer,” said Jennifer Caddick, executive director of Save The River.” In recent years, we have watched ships plow through two feet of ice just yards off our shoreline.”

In the 1970’s environmental groups throughout the Great Lakes region banded together to persuade Congress to defeat an Army Corps of Engineers proposal for winter navigation on the Great Lakes. Nine years of feasibility demonstration projects had clearly shown that icebreaking to keep winter shipping lanes open was not only economically impractical, but also responsible for severe damage to fish and wildlife habitats. Today, a flexible opening date set by the St. Lawrence Seaway has allowed the season to get longer, effectively undermining the decision not to implement winter navigation.

Ship wakes in a winter ice environment are concentrated under the ice, increasing bottom erosion and scouring.  Further, the potential for oil releases from normal shipping operations and from catastrophic releases during oil or hazardous cargo spills is increased during winter shipping and the cleanup of spills in the winter is more difficult.

“In ice conditions many spill response assets, including boats and boat launches, necessary for effective spill response are not available,” says Caddick. “STR is committed to standing up for the citizens who have watched the River suffer because of the Seaway’s winter shipping practices.”