The World's largest High Arctic Lake Responds Rapidly to Climate Change
published in: Nature Communications (29 March 2018) Read the paper
For further information, please contact Igor Lehnherr (igor.lehnherr@utoronto.ca or 905-865-5226)
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Press release
Lake Hazen quick facts:
We found that the world’s largest High Arctic lake by volume has experienced large and important changes despite only a 1oC increase in summer climate warming. Lake Hazen, situated on northern Ellesmere Island in the middle of Canada’s most northerly National Park (Quttinirpaaq National Park), receives the majority of its water from melting glaciers in its watershed each summer. Recently, those glaciers have begun to melt more each year than they have been growing, resulting in 10-time increases in delivery of glacial meltwaters, sediments and organic carbon from the landscape, and contaminants, such as mercury and pesticides previously locked up in glacial ice. Also, due to warming in the region, Lake Hazen is now going ice-free each summer, something that rarely happened in the past. These changes to Lake Hazen have caused the algal community in the lake to shift dramatically to species favoring open water, and the physiological condition of the only fish species in the lake, Arctic Char, to decline significantly. All these changes shift Lake Hazen and its watershed into a state that is unprecedented within at least the past ~300 years.
“What our study shows is that even in the High Arctic, warming is now occurring to such an extent that it is no longer cold enough for glaciers to grow, and lake ice to persist year-round” says lead author Igor Lehnherr, an assistant professor in the Department of Geography at the University of Toronto-Mississauga. “This warming has important impacts on most aspects of the Lake Hazen watershed, from the glaciers in the mountains to the fish in the lake.”
We originally hypothesized that, because of its large volume, Lake Hazen would be relatively resilient to the impacts of Arctic warming. The finding that this was not the case is alarming because the Arctic is the most rapidly warming region on the planet, with conservative estimates predicting further warming of another ~ 4 oC by the end of the century. Due to the scale of the whole-watershed and ecological changes that we documented, and which occurred in response to a relative summer air temperature increase of only 1oC, we warn that any further warming of northern high latitudes will jeopardize sensitive ecosystems, the security of traditional freshwater foods such as Arctic char, and other services provided by freshwater ecosystems for northern Indigenous peoples throughout the Arctic.
“Lake Hazen is important in it’s own right, as a cultural and natural heritage site, but it also serves as a key sentinel for the impacts of human-caused climate change in the Canadian High Arctic”, comments Igor Lehnherr. “It is very difficult to measure environmental change in this part of the world, due to the remote location which poses significant logistical and financial challenges.”
Lake Hazen quick facts:
- Where: 900 km from the North Pole and 4300 km from Toronto, Lake Hazen is located on Ellesmere Island (Nunavut) in Quttinirpaaq National Park
- How big: 267 m deep, 540 km2 in surface area, Lake Hazen is the largest lake north of the Arctic Circle
- Who: Since circa 2500 BC, a succession of Arctic indigenous cultures, including modern Inuit, have hunted muskox and fished Arctic char in the Lake Hazen region. The only settlement on Ellesmere Island is Grise Fiord, located on the south coast of the island, and is about 650 km from Lake Hazen.
We found that the world’s largest High Arctic lake by volume has experienced large and important changes despite only a 1oC increase in summer climate warming. Lake Hazen, situated on northern Ellesmere Island in the middle of Canada’s most northerly National Park (Quttinirpaaq National Park), receives the majority of its water from melting glaciers in its watershed each summer. Recently, those glaciers have begun to melt more each year than they have been growing, resulting in 10-time increases in delivery of glacial meltwaters, sediments and organic carbon from the landscape, and contaminants, such as mercury and pesticides previously locked up in glacial ice. Also, due to warming in the region, Lake Hazen is now going ice-free each summer, something that rarely happened in the past. These changes to Lake Hazen have caused the algal community in the lake to shift dramatically to species favoring open water, and the physiological condition of the only fish species in the lake, Arctic Char, to decline significantly. All these changes shift Lake Hazen and its watershed into a state that is unprecedented within at least the past ~300 years.
“What our study shows is that even in the High Arctic, warming is now occurring to such an extent that it is no longer cold enough for glaciers to grow, and lake ice to persist year-round” says lead author Igor Lehnherr, an assistant professor in the Department of Geography at the University of Toronto-Mississauga. “This warming has important impacts on most aspects of the Lake Hazen watershed, from the glaciers in the mountains to the fish in the lake.”
We originally hypothesized that, because of its large volume, Lake Hazen would be relatively resilient to the impacts of Arctic warming. The finding that this was not the case is alarming because the Arctic is the most rapidly warming region on the planet, with conservative estimates predicting further warming of another ~ 4 oC by the end of the century. Due to the scale of the whole-watershed and ecological changes that we documented, and which occurred in response to a relative summer air temperature increase of only 1oC, we warn that any further warming of northern high latitudes will jeopardize sensitive ecosystems, the security of traditional freshwater foods such as Arctic char, and other services provided by freshwater ecosystems for northern Indigenous peoples throughout the Arctic.
“Lake Hazen is important in it’s own right, as a cultural and natural heritage site, but it also serves as a key sentinel for the impacts of human-caused climate change in the Canadian High Arctic”, comments Igor Lehnherr. “It is very difficult to measure environmental change in this part of the world, due to the remote location which poses significant logistical and financial challenges.”
For further information, please contact Igor Lehnherr (igor.lehnherr@utoronto.ca or 905-865-5226)
Official University of Toronto press release
Read the paper (open access)
Other press coverage related to this paper can be found here
Official University of Toronto press release
Read the paper (open access)
Other press coverage related to this paper can be found here
Footage of scientists working at Lake Hazen: |
