Svalbard’s polar bears are among the least threatened under current global climate conditions, but are facing the most drastic best-to-worst scenario and being among those most likely to go extinct during the next several decades due to climate change, according to a study published Monday.
The study, summarized in widespread global headlines such as “most polar bears to disappear by 2100,” declares polar bears in Svalbard and the rest of the Barents Sea region face an “inevitable” risk of reproductive failure by 2100 if greenhouse gas emissions continue at current levels and a “very likely” risk if emissions are moderately mitigated. Currently the region’s bear population is among a relative few across the Arctic facing no such risk, according to the study.
But with Svalbard warming twice as fast as other Arctic regions and seven times faster than Earth’s average, according to another recent study, the threats to the species detailed in Monday’s report – such as prolonged fasting and reduced nursing of cubs by mothers as vanishing sea ice means longer periods of being away from food sources – are greatly magnified.
“It’s important to highlight that these projections are probably on the conservative side,” Steven Amstrup, chief scientist for Polar Bears International and a co-author of the study, told The Guardian. He said the models may include optimistic assumptions about the body condition of bears at the start of fasting periods and how much energy bears use to maintain conditions so “the impacts we project are likely to occur more rapidly than the paper suggests.”
The study examines 13 of the world’s 19 subpopulations of polar bears, representing about 80 percent of the total population. It examines threat levels if emissions levels are unchanged (resulting in global temperature increase of 3.3 degrees Celsius about preindustrial levels by 2100) and if they begin to decline after peaking in 2040 (resulting in an increase of 2.4 degrees).
All polar bears except those in the Queen Elizabeth Islands in northern Canada would be wiped out under a no-change scenario and even under a reduced emissions scenario a majority of the populations will experience reproductive failure by 2080, according to the study.
In Svalbard temperatures have already risen about five degrees since the 1970s and may increase anywhere from five to 15 degrees more in some parts of the archipelago during certain seasons (the most extreme increases occurring in the northernmost part during winter).
Currently the Barents Sea region is among a relative few with the lowest-level of risk to the species, according to the study. Under a reduced-level scenario it would join a plurality of Arctic regions at the “very likely” risk level, the highest in that scenario – and be the only current “no-risk” area in that group. The best-to-worst shift is even more drastic under a no-change scenario as it would be one of two areas with an “inevitable” reproductive collapse of the species, joining Canada’s southern Hudson Bay which at present is rated as “likely” to suffer such a collapse.
The threats and shifts to populations will occur long before the end of the century, the study warns.
“In some regions they are already caught in a vicious downward spiral, with shrinking sea ice cutting short the time bears have for hunting seals,” the report states. Their dwindling body weight reduces their chances of surviving winters without food.
There are roughly 25,000 polar bears worldwide, according to the most recent counts. Svalbard’s population rebounded strongly after hunting was outlawed in 1973, and has managed to remain relatively stable during the past decade or two despite profound changes in climate and sea ice conditions. Researchers have attributed the stability in part to bears increasingly seeking alternative food sources, often on land such bird eggs, and migrating to areas in the region (often north and east of Svalbard) where hunting is possible.
But rapidly vanishing sea ice means even limited hunting periods and migration possibilities will vanish, possibly within the the next decade or two. The global sea ice extent during summer has declined about 13 percent per decade compared to the 1981-2010 average and this year is on pace to set another record low, according to the Japanese Aerospace Exploration Agency.
As with all studies, the researchers emphasized their findings are subject to uncertainties, especially in some areas such as parts of Russia due to a lack of available data. The country, for example, backed out of a planned joint Norwegian-Russian census of the Barents Sea polar bears several years ago, thus resulting in the current estimate of 2,700 being a median estimate in a population that may range from 1,900 to 3,600.
And of course plenty of skeptics, from laypersons to notorious climate change deniers with academic credentials, quickly weighed in with their doubts.
Susan Crockford, whose Polar Bear Science blog has been cited as the primary source for the vast majority of climate skeptic blogs and online commentary, responded immediately with a post declaring the findings “not scientifically plausible.” She claims it used out-of-date findings from one part of northern Canada more than a decade ago and “the most extreme and now discredited” warming scenarios to make vague projections (‘possible’, ‘likely’, ‘very likely’) about all other subpopulations.”
“(Those are) all that’s needed to dismiss it as exaggerated-fear-mongering-by-proxy,” she wrote. “Why would anyone believe that the output of this new model describes a plausible future for polar bears?”
(Editor’s note: yes, the context and accuracy of her assertions can be challenged as well, but as with most climate change articles a full point-by-point breakdown of all claims and counterclaims goes way beyond reasonable expectations of what a journalist can write and reader can absorb in an ordinary newspaper story. The above is merely to illustrate how the so-called “debate” is likely to take form.)
At the “commoner” level, the readers comments in an article published by The New York Times about the study span an above-average range from reasoned debate to eclectic social commentary and suggested solutions.
“Polar bears survived the Eemian interglacial during which Arctic temperatures were 5 degrees F warmer than present, the Arctic was pretty much ice free, and sea level was as much as 20 feet higher than present,” wrote a commenter with the username Thomas J. Pain from Coos Bay. “I think they’ll have no problem getting through the next 80 years.”
That began a long thread, starting with a dissenting opinion by “B Fagen” from Chicago.
“They had to deal with oil exploration and overfishing and the killing of most whales back then, too?” the rebuttal noted, adding that man-man CO2 emissions mean the rise once caused by natural cycles is unlikely to occur now.
“Justin the Moon” thinks polar bears don’t have much to worry about – but only because humans are the ones at risk.
“At the rate we are going, I am confident societal collapse in the next few decades will cause a significant decrease in emissions and save the polar bear from extinction,” the commenter wrote.
As for all the pollution humanity is causing, “Steve” from Savannah suggests it be used for the bears’ benefit.
“Why can’t engineers drag some of the earth’s surplus styrofoam into the Arctic and design huge floating islands that the bears can survive on?” he wrote.