World's largest high Arctic lake shows startling new evidence of climate change

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Lake Hazen, located on northern Ellesmere Island in Canada’s far north is, by volume, the largest lake north of the Arctic  Circle. Arctic indigenous people’s first arrived at Lake Hazen circa 2500 BC. At various times since then, a succession of arctic-adapted cultures, including the modern Inuit, have hunted muskox in the region and fished Lake Hazen’s plentiful population of Arctic Char. 

Lake Hazen has a maximum depth of 867 feet, a surface area of 335 square miles and a catchment area of 4,260 square miles. “The NW half of its catchment is extensively glaciated, while the Hazen Plateau characterized by polar desert tundra lies to the SE. Lake Hazen is an ideal system for examining the impacts of recent climate change on Arctic freshwater ecosystems due to its large size, the variety of ecosystems found within its watershed (including glaciers, tundra, wetlands and other aquatic ecosystems), its location within protected Quttinirpaaq National Park”.

Researchers found that Lake Hazen is reacting rapidly to warming global temperatures in a once stable region of the Arctic.

Location of the Lake Hazen watershed and changes in glacier surface temperatures. Changes in summer glacier surface temperatures (°C y−1) were quantified for the months of June, July and August for the period 2000–2012. The white line delineates the boundaries of the Lake Hazen watershed, and the glaciers within it (northern Ellesmere Island, Nunavut, Canada). The catchment area to lake area ratio for Lake Hazen is 12.7. The black line delineates the boundary of Quttinirpaaq National Park, Canada’s most northerly national park

University of Toronto news release on the newest horrors being discovered in the Arctic:

“Even in a place so far north, it’s no longer cold enough to prevent the glaciers from shrinking,” says the U of T Mississauga geographer and lead author of the study. “If this place is no longer conducive for glaciers to grow, there are not many other refuges left on the planet.

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“We showed that climate  has many different impacts, and all components of the watershed are intricately connected,” he says. “The physical, biological and chemical aspects are responding directly to climate changes.”

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“The lake and the lake ecosystem have been in a relatively stable state for hundreds of years, but all it took was a one-degree increase in regional air temperature for it to enter a completely new state,” Lehnherr says. “The biological food web looks different, the biogeochemical cycles are accelerated, and we’re observing more organic nutrients, contaminants and carbon coming into the system.”

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“The glaciers typically melt a little during the spring and summer seasons, however we noticed that they began to lose more ice than they gained in the winter,” says Lehnherr. “We are now seeing the ice mass declining, which is surprising, because the lake is one of the most northerly of Canadian lakes. Water takes a lot of energy to warm up, and can store a lot of heat energy. A large lake, like Lake Hazen, theoretically should be more resilient to climate change relative to a pond or smaller body of water. If this lake is exhibiting signs of climate change, it really shows how pervasive these changes are.

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From the study.

In this study, we investigate how a warming climate has impacted the Lake Hazen watershed from its glacier headwaters, all the way through to the Arctic Char at the top of the aquatic foodweb, using a combination of historical, contemporary, modeled and paleoliminological datasets. We hypothesized that, due to its large size and thermal inertia, Lake Hazen would be more resilient to Arctic warming (c.f. ref.12) than smaller aquatic ecosystems, a number of which have already undergone significant regime shifts13,14,15. However, we demonstrate that the Lake Hazen watershed was not resilient to even an ~1 °C relative increase in recent summer air temperatures. Accelerated melt in the cryosphere resulted in an ~10 times increase in delivery of glacial meltwaters, sediment, organic carbon and legacy contaminants to Lake Hazen and a reduction in summer lake ice cover. Changes to the physical and chemical components of the watershed caused an ecological reorganization of the algal (diatom) community assemblage and a decline in the physiological condition of Arctic Char.