Lake Erie may experience a slight relief this summer as the National Oceanic and Atmospheric Administration (NOAA)—the U.S. government body in charge of weather forecasts and climate monitoring—predicts that the Great Lake will experience a below-average harmful algal bloom.
This year’s bloom is expected to measure at a 3.5 on the harmful algal bloom severity index. The index ranges from one to 10 and is based on the bloom’s biomass—or amount of algae—during the bloom’s peak 30 days. Numbers under three indicate a relatively small bloom, while numbers over five indicate a severe bloom, and numbers over seven indicate a very severe bloom with extensive lake coverage.
This year’s 3.5 isn’t guaranteed, though. Depending on weather conditions, the number could be bumped up. Last year, the NOAA predicted a severity index of three for Lake Erie and the bloom eventually reached a severity index of six. Lake Erie has grappled with harmful algal blooms for the past 14 years with the largest blooms occurring in 2011, at a 10, and in 2015, at a 10.5.
What makes these blue-green algal blooms so harmful is their potential to produce microcystin, a liver toxin that, if ingested, can cause sickness in humans—and even death in extreme cases—as well as kill fish, birds, and mammals. Not all algal blooms produce this toxin, but scientists have yet to create an accurate method for predicting bloom toxicity as it isn’t dependent on bloom size.
Toxic blooms have been known to contaminate drinking water. In August 2014, half a million people in Toledo, Ohio were unable to drink, cook, or brush their teeth with tap water due to a harmful algal bloom growing in Lake Erie. The blooms also impact Lake Erie’s fishing and tourism economies, which generate an estimated $65 million, annually.
Even if a bloom doesn’t produce microcystin, it can still cause problems, such as sucking the oxygen out of the water, clogging the gills of fish, and smothering other aquatic vegetation.
So far, this year’s algal bloom is contained in Lake Erie’s western basin, near Toledo. The NOAA says the bloom should stay there, leaving the northern and eastern basins touching Ontario unaffected. “Although, localized blooms may occur around some of the rivers after summer rainstorms,” the NOAA added.
Scientists have figured out a few factors that contribute to algae growth, but have yet to determine how these factors interact to create the algae.
“With ten years of experience with forecasts we understand more about the blooms, including evidence that big river discharge events in mid-summer may matter more than we thought,” said Richard Stumpf, NOAA’s lead scientist on the seasonal Lake Erie bloom forecast, in a statement.
These discharge events sweep nutrients from agricultural runoff, such as nitrogen and phosphorus, into the lake. “Recent research has found that a long-term increase in the frequency of heavy rainfall events due to climate change may be causing more runoff during spring and summer months because the soil has less time to absorb the rain,” the NOAA said.
In addition to nutrient runoffs, algal blooms seem to thrive when water is slow-moving, temperatures are warm, and there’s lots of sunlight. The NOAA said it’s too early to predict how long this bloom will last as it will depend on the frequency of wind events in September.
Currently, there’s no way to clean up algal blooms, so it’s best to avoid them. If you are swimming in an affected body of water, look for dead fish in or near the water and the appearance of blue or green spilled paint on the surface of the water as an indication of a bloom.
The NOAA will release an updated forecast on the Lake Erie algal bloom based on rainfall data in late July.
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The Great Lakes hold one-fifth the standing freshwater on the Earth’s surface and more than 34 million people live in the basin, supporting an economy worth US$5 trillion—if it were a country, it would be one of the largest economies in the world. And yet shoreline communities are faltering under the weight of billions of dollars in damages—and are worried that climate change will continue to make things even worse.
With the UN climate conference in Glasgow (COP26) underway, world leaders are discussing what must be done to address the climate crisis and making pledges to take specific actions. Adaptation features heavily in the COP26 agenda, including the Glasgow Adaptation Imperative to assess action taken and action needed to meet the Paris Agreement goal on adaptation and promote a more climate resilient future for all, particularly the most vulnerable communities and ecosystems.
Climate change impacts
In the Great Lakes, climate change is considered a threat multiplier, meaning it exacerbates other threats to the ecosystem.
The Great Lakes have lost more than 70 per cent of their total winter ice cover over the past 50 years. That means more open water during winter, thinner ice and less of the ice fishing that is so popular with basin denizens. Less ice cover will, however, lengthen the commercial shipping season.
Ice fishing is popular among those living near the Great Lakes. But as air temperatures rise in the winter, the ice is thinner and is in place for a shorter time. (Photo by Marianne Danielsen/Shutterstock)
Overall, warming of the lakes will alter the seasonal patterns of warm and cold water layers and the dynamics of the lakes’ food webs, and it will lead to greater shoreline damage from strong winter storms.
In some areas within the Great Lakes basin, water levels have risen by two metres, eroding shorelines, washing away houses, destroying roads, threatening infrastructure such as water treatment plants and disrupting age-old traditions of Indigenous Peoples.
Climate change is one of the leading threats to birds in the Great Lakes and North America. The 2019 Audubon Report “Survival by Degrees” found that 64 per cent of bird species (389 of 604) across breeding and non-breeding seasons were moderately or highly vulnerable to climate change. As indicator species, birds are telling us the time to act is now.
In addition, climate change will likely alter the range and distribution of certain fish species, increase the frequency and severity of harmful algal blooms, exacerbate wetland loss, create new threats from invasive species, diminish beach health and, in some cases, displace or extirpate native species.
Urban impacts of climate change
The effects of climate change are heightened in urban areas and impose a high financial burden to municipalities. Detroit is a good example.
Detroit is an old city with combined storm and sanitary sewers that overflow stormwater and raw sewage during heavy rainfall events. It also has plenty of impervious surfaces that promote runoff.
Extreme rainfall events have flooded highways, streets and neighbourhoods. High water levels have frequently flooded Detroit’s Jefferson-Chalmers neighbourhood. In response, the city spent US$2 million in 2020 on “tiger dams,” large, temporary, water-filled berms, to keep the water from flooding houses.
On the 398-hectare Belle Isle State Park, high water levels closed roads, flooded picnic areas and postponed 60 weddings at the popular Boat House, a more than 100-year-old rowing facility, in 2019. They have also delayed a US$5-million habitat restoration project on Blue Heron Lagoon and forced the redesign of the one-hectare, US$4.2-million Oudolf Garden, designed by Piet Oudolf, an internationally renowned Dutch garden designer.
Detroit is also projected to experience a significant increase in the number of very hot days by the end of the century, reaching as many as 65 days above 32.2 C. The burden of heat and poor air quality accompanying the climate threat will disproportionately affect the city’s most vulnerable residents.
Adapting to climate change
Many municipalities, provinces and states around the Great Lakes have been developing adaptation plans to address local impacts of climate change at a high cost. This decentralized approach comes with its own problems, like unintended cross-border effects of local adaptation or duplication of efforts. The United Nations has shown that flood risk reduction strategies in one part of a basin may increase flood risks in another portion of the basin that is located in another country.
A small home along Lake Michigan’s shoreline toppled down a bluff in January 2020.
An integrated, basin-wide ecosystem approach could allow for cost-sharing of scientific studies and co-ordinated policy action at national and sub-national levels, leading to better adaptation. Because the Great Lakes are a shared resource among many governments, including those of Canada, the United States, eight states, two provinces and tribes, First Nations and the Métis Nation, transboundary co-operation is needed.
The Great Lakes Water Quality Agreement calls for strengthened measures to anticipate and prevent ecological harm, by following the precautionary principle—when human activities may lead to unacceptable harm that is scientifically plausible but uncertain, actions shall be taken to avoid or diminish that harm.
There is enough scientific evidence that climate change poses a threat to the entire Great Lakes region—and the 38 million people who live there. As is being discussed and pledged at COP26, all must work together to limit global warming to 1.5 C, including the Great Lakes region, and all must immediately advance climate adaptation and resilience.
This story is part of The Conversation’s coverage on COP26, the Glasgow climate conference, by experts from around the world. More.This article is republished from The Conversation under a Creative Commons license. Read the original article.
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