Arctic Ice Loss to Bring Six-Metre Waves, More Coastal Erosion
An ice-free Arctic summer will bring surging ocean swells to northern seas by 2080—meaning community-battering coastal waves and six-metre mid-ocean monsters that will menace ship traffic.
Reporting on research from Environment and Climate Change Canada that was published last week in the Journal of Geophysical Research, the Globe and Mail writes that such an increase in summer wave action will particularly threaten coastal communities in Canada’s western Arctic and Greenland’s east coast.
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Already fighting a rearguard action against melting permafrost that is causing homes and sacred burial sites to fall into the sea, villages like Tuktoyaktuk, Northwest Territories will increasingly need to defend themselves against an ocean that roils ashore even on calm days. The Canadian researchers also found that “floods and other extreme events that currently occur about once every 20 years could show up every two to five years,” reports the Globe.
Just how much increased erosion will affect coastal Arctic communities as summer sea ice vanishes is an under-researched question that climate scientist Mercè Casas-Prat and ocean wave specialist Xiaolan Wang sought to answer with the study.
“The pair looked at the heights and periods of waves found in the Arctic Ocean between 1979 and 2005 and then used climate models to estimate how much those characteristics are likely to change,” writes the Globe. To eliminate uncertainty, Casas-Prat and Wang also ran their projections through five climate models.
“Some of the general patterns were expected, but seeing how much it will increase is a bit surprising—I would say alarming,” said Casas-Prat. More open sea water means more surface area, called “fetch”, for wave-generating winds to move across and act upon. The weight of sea ice would once have acted to supress those waves—“particularly during the fall when Arctic seas are at their stormiest,” explains the Globe. But as that ice melts, there will be little left to subdue the waves and protect the coastline.
Such changes also bode ill for the commercial ships that are expected to traverse Arctic waters in increasing numbers as the climate warms and the sea ice vanishes, Casas-Prat warned.
While the new study did not take into account the possible mitigating impacts of the broad continental shelf that pushes out from Alaska’s north coast, nor the possibility that increasing wave action will actually mean an ice-free Arctic summer “well before 2080,” physical oceanographer Li Erickson of the U.S. Pacific Coastal and Marine Science Center in Santa Cruz, California lauded the new study as a significant addition to the complex science of Arctic sea ice loss. “It’s really a step forward,” she said.