Posted by: Vicki Burns | November 16, 2015

Climate Change Impacts Lake Winnipeg Water Levels and Blue-Green Algae

Grand Beach June 2014

It seems that every day now we are seeing news items in mainstream media about climate change and the upcoming COP21 meetings in Paris on Nov.30, 2015. Many of us, Canadians, are hoping that our federal government, under the recently elected Trudeau Liberals, will take a much more proactive approach to reducing our CO2 emissions. Canada has been infamous for receiving the fossil award at international meetings in recent years and that is a designation we want to see gone.
I’m encouraged to see so much more attention in mainstream media about climate change because I think there are still quite a number of people who have not fully accepted that this is very real challenge we face.  It seems to me that if we can identify how climate change has already impacted some of the areas where we live, it will help to broaden acceptance and support for the changes we’ll all need to make.
Last month I posted a blog about the impact of climate change on Lake Winnipeg and other North American lakes. I focussed primarily on the issue of much longer ice-free days on our lakes due to warming temperatures resulting in earlier spring ice break-up and later fall freeze-up. That translates into longer growing seasons for algae. Recently I received this report authored by Dr. Greg McCullough, of the University of Manitoba’s Centre of Earth Observation Science. It highlights a different impact of climate change on Lake Winnipeg – the greatly increased flow into the lake from both the Red River and the Winnipeg River which results in increased flow of phosphorus as well.
The annual flow from the Red River into Lake Winnipeg has increased 160% between 1920 and 2010 while the flow from the Winnipeg River has gone up 53%.  These increased flows are a result of more intense weather events (snow and rain storms) as well as drainage of a huge percentage of wetlands within the watershed. It is well recognized that the flow of phosphorus (the nutrient that feeds the blue-green algae) into the lake is greatly increased with storm events, thus adding to the impact of climate change.
These increased flows into Lake Winnipeg (along with isostatic rebound) have resulted in the level of the lake averaging one foot higher than it was in the early 20th century. Without Hydro’s regulation of the lake, it would have been 2 feet higher on average (2002 -2011) with isostatic rebound accounting for .7ft. and increased flows accounting for the other1.3 ft.
To summarize, climate change is impacting Lake Winnipeg and many other lakes by contributing to the proliferation of blue-green algae, much of which contains dangerous toxins. There are many good reasons for all of us to work to increase efforts to decrease emissions causing climate change, not the least of which is the threat to clean, safe water in our lakes.

 

 

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