One of Earth's air conditioners is set to release its vast store of fresh water into the North Atlantic, which could have "significant" impacts on the Northern Hemisphere's climate, including the breakdown of the Atlantic Meridional Circulation Current.
The anticyclonic Beaufort Gyre is located north of Alaska and Canada's coastlines. Before the Great Acceleration of Industrialization at the beginning of the 1950s, sea ice would circulate for several years in the Gyre, which led to the formation of what is referred to as thick multi-year ice or old sea ice.
Fresher water reaches the Arctic Ocean through rain, snow, rivers, inflows from the relatively fresher Pacific Ocean, as well as the recent melting of Arctic Ocean sea ice. Fresher, lighter water floats at the top, and clockwise winds in the Beaufort Sea push that lighter water together to create a dome. When those winds relax, the dome will flatten and the freshwater gets released into the North Atlantic.
But global warming has taken a heavy toll on the Arctic's sea ice nursery, where newly formed ice could at one time mature and grow. Due to warming, little mature ice is left, and the resultant melt adds fresh water to the Gyre. The release of all that cold water would be disastrous as it would be pushed to Europe, disrupting fisheries and making the northwestern part of the continent colder.
From Wiki:
Housed in the western part of the Arctic Ocean is the Beaufort Gyre, whose growing reservoir of freshwater is shrouded in mystery. In recent years, this increasing freshwater content (FWC) has been the focal point of many studies, particularly those concerning coupled ocean-atmosphere dynamics. The majority of the Arctic’s freshwater content resides in the Beaufort Gyre. Although biased toward the Northern Hemisphere summer months, observations from submarines, ships, and stations on drifting ice suggest that the gyre has been expanding over the past two decades.
The presser from the Woods Hole Oceanographic Institution describes the study's findings.
The Beaufort Gyre “has transitioned to a quasi-stable state in which the increase in sea surface height of the gyre has slowed and the freshwater content has plateaued. In addition, the cold halocline layer, which isolates the warm/salty Atlantic water at depth, has thinned significantly due to less input of cold and salty water stemming from the Pacific Ocean and the Chukchi Sea shelf, together with greater entrainment of lighter water from the eastern Beaufort Sea. This recent transition of the Beaufort Gyre is associated with a southeastward shift in its location as a result of variation in the regional wind forcing,” according to the journal article “Recent state transition of the Arctic Ocean’s Beaufort Gyre,” published in Nature Geoscience.
“Our results imply that continued thinning of the cold halocline layer could modulate the present stable state, allowing for a freshwater release,” the article states. “This in turn could freshen the subpolar North Atlantic, impacting the AMOC.”
Because there could be many potential local and remote impacts of the changing gyre on the hydrographic structure, physical processes, and ecosystem of the Arctic, “it is of high interest to better understand the factors associated with such changes—including the underlying causes,” the article notes.
“People should be aware that changes in the circulation of the Arctic Ocean could threaten the climate. It’s not only the melting ice and animals losing their habitat that should be a concern,” said Peigen Lin, lead author of the paper. Lin, who is an associate professor at the Shanghai Jiao Tong University’s School of Oceanography in China, conducted his research as a postdoctoral investigator at the Woods Hole Oceanographic Institution (WHOI) in Massachusetts.
With the gyre being the Arctic Ocean’s largest freshwater reservoir, “if that freshwater gets released and ends up spreading into the North Atlantic, it could impact the overturning circulation, and, in an extreme case, disrupt it,” said co-author Robert Pickart, a senior scientist in WHOI’s Department of Physical Oceanography.
The study, which includes an examination of long-term trends of the Beaufort Gyre and the causes of the thinning of the cold halocline layer, quantifies the evolution of the gyre in terms of its sea surface height as well as its freshwater content. “Both of these indicate that the Beaufort Gyre has stabilized in the second decade of this century,” Lin said.
The job now is for the Beaufort Gyre mechanisms to be closely monitored so scientists can understand what it may do in the future.
Their experiment showed that most of the freshwater reached the Labrador Sea through the Canadian Archipelago, a complex set of narrow passages between Canada and Greenland. This region is poorly studied and was thought to be less important for freshwater flow than the much wider Fram Strait, which connects to the Northern European seas.So the gyre just keeps getting bigger, spinning faster and collecting more water, Struzik says. “Imagine all of the water that we have in the Great Lakes — that’s the amount of freshwater trapped in the Arctic just waiting to get out.”
Scientists are waiting with bated breath, he says. They see signals that the gyre could reverse sooner rather than later, but they thought this was the case in 2013 and it turned out not to be. When it does happen, Struzik says, we won’t see a "The Day After Tomorrow" scenario, in which the world goes into a deep freeze, but it's definitely going to “create some problems" for the European countries near the North Atlantic. The last time this happened, in the 1960s and 1970s, western Europe endured eight of its most severe winters and the surge of ice and freshwater disrupted the North Atlantic food chain; this, in turn, caused a collapse of the lucrative herring fishery.
Hypothetically, a quickly warming Arctic and its effect on the gyre could impact weather across North America, as well. Warming Arctic waters appear to be disrupting the flow of the jet stream, creating a kind of “loopiness” in its shape that tends to hold weather patterns in place, Struzik explains. This can bring Arctic air further south than usual and create unusual extreme weather events, like what recently occurred in Corpus Christi, Texas, which received several inches of snow a few weeks ago.
Our primary job will be to fight the Fossil Fuel industry tooth and nail. I suggest we nationalize the industry and begin a severe drawdown of fossil fuels with the least amount of pain possible.
We are in serious trouble, folks, be kind to each other.
Video by Woods Hole Oceanic Institution three years ago.