Warming temperatures and declining sea ice are fueling more frequent and powerful storm surges in an Arctic region rich in oil and gas reserves, according to a new study.
The findings raise new concerns about the vulnerability of the delicate ecosystem in the outer Mackenzie Delta in Canada's Northwest Territories, home to indigenous communities, natural resources, vegetation and animal life. Previously, scientists had suspected that warming Arctic temperatures enhanced storm surges in the region, but they lacked specific details.
"As the Arctic continues to warm, we need to plan for greater storm surge activity in low-lying Arctic coastal environments," said Jesse Vermaire, a former postdoctoral fellow in the Department of Geography and Environmental Studies at Carleton University in Ottawa, Ontario. Vermaire was the lead author of the study, published online in Geophysical Research Letters.
"Future climate warming will make Arctic coastal regions increasingly hostile environments," the study says.
Declining Arctic ice is the driver of more powerful storm surges in the outer Mackenzie Delta, said Joshua Thienpont, a doctoral candidate at Queen's University in Ontario and co-author of the research. Last year, the National Snow and Ice Data Center reported that Arctic sea ice had hit record lows.
Storms strengthen in open water
As Arctic ice thins, it creates more areas of open water for storms to gather energy and bring in more powerful surges, said Theinpont. Additionally, climate change is creating higher sea levels that also can boost surges, he said.
To reach their conclusions, the scientists extracted cores from the muddy bottoms of three lakes in the delta. The cores provided clues about the past 400 years, by holding a record of very old sediment.
In normal conditions, the particles gathering in the lakes are quite small, carried by wind and other factors, said Thienpont. That was the case hundreds of years ago, according to the data.
But with more powerful storm surges, large sand particles are flushed into the lakes from the ocean, he said.
Over the past 150 years in particular, the team found evidence of large marine particles in the core data. Their presence indicates that greater storm surges moved in tandem with higher temperatures and declining sea ice over the same period, the researchers said.
"Although storm surges have regularly influenced the outer delta, the severity of the surges is affected by climate warming," the study says.
The scientists did not find a similar connection between temperature and storm surges in a core from a lake at higher ground outside of the storm flooding zone. That enforces the study's conclusions about a linkage between declining sea ice and storm surges, said Theinpont.
The storm surge phenomenon is worsened by the fact that Arctic sea ice hits its minimum in September, during the Arctic storm season, he said. The scientists also concluded that an unusually powerful storm surge in the region in 1999 was the most severe such event in at least the past 400 years.
More risks for oil and gas explorers
That storm created a "dead zone" of roughly 29,000 acres, where saltwater inundation killed off vegetation, driving away animal life and hunters and trappers.
"When you fly over it, it is brown," said Theinpoint. "It used to be green."
An earlier 2011 study in the Proceedings of the National Academy of Sciences found that saltwater flooding from the 1999 storm killed more than half of the shrubs in the area within a year and an additional 37 percent within five years.
With climate change continuing to melt Arctic sea ice, there definitely is a risk that similar "dead zones" could become more common, he said. More storm surges could threaten places such as Tuktoyaktuk, an Inuit community in the Northwest Territories about 45 miles from the studied lakes, he said.
While more research needs to be done, it is a likely possibility that further work will show similar storm surge increases in additional parts of the Arctic, said Thienpont.
"One important implication of our research is that in developing [oil and gas] resources, managers need to plan for more extreme weather events," Vermaire said.
Another study also published online in Geophysical Research Letters holds an additional warning about the Arctic.
It finds that some global climate models may be far too conservative about predicting when the Arctic will be ice-free in the summer. There is a possibility of a nearly sea ice-free summer in the Arctic within the next decade, according to the research.
"It is reasonable to conclude Arctic sea ice loss is very likely to occur in the first rather than the second half of the 21st Century," says the study, which was led by National Oceanic and Atmospheric Administration oceanographer James Overland.
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