Ice-Free Alaskan Waters No Problem for Polar Bears & Walruses
Written by Susan J Crockford PhD
One of two alarming headlines that caught my eye this week was the ‘news’ on Monday that the waters off Alaska were now ice-free because of climate change, courtesy a story in the online media outlet Mashable that was later picked up by The Weather Channel and the UK mainstream paper The Independent.
In addition, a large number of mainstream news outlets, including the New York Times and Newsweek, have reported that walruses came ashore this year at Point Lay, Alaska, two weeks earlier than any year since 2007.
No one claimed this late July onshore movement of walruses was the beginning of the end of walruses but it was still blamed on human-caused climate change because it was associated with the aforementioned ice loss in Alaska.
Neither event was really ‘news.’ Moreover, neither an ice-free Alaska in early August or walruses onshore two weeks earlier than 2017 will have any negative impact on local polar bear or walrus populations, whether due to human-caused climate change or natural variation.
Well-fed polar bears everywhere are quite capable of going 4-5 months without food in the summer and a few thousand walruses at Point Lay will feed happily from this shore-based haul-out for a few days to a few weeks as they have done many summers since 2007 before moving on to other Chukchi Sea beach locations – although the ‘leaving’ events never seem to get any media attention.
Walruses will haul-out on beaches in Alaska and Russia until the ice returns in October.
Here is the map that Mashable story on an ice-free Alaska included, which indeed shows a vast area of open water off Alaska [note theirs is dated two days earlier, on 4 Aug.]:
However, what the Mashable story didn’t show is the related chart that shows the age of the remaining pack (see below), which is very thick multiyear ice. Such thick ice might thin out a bit by September but it is in no danger of disappearing:
Any bear that had chosen to spend the summer on an Alaskan beach in 2016 would have spent 3-4 months ashore – something that bears in Hudson Bay, Davis Strait, and the Baffin Bay have done on a regular basis for as long as they have been studied and more recently, they have spent almost five months ashore without serious problems.
Despite the large expanses of open water this year in the Beaufort Sea, there have been no media reports of unusual numbers of problem bears or bear attacks along the coast of Alaska.
As for the walrus story, the Associated Press account authored by Don Joling points out that the US Fish and Wildlife Service determined in 2017 that Pacific walrus are not threatened with extinction because of recent declines in Arctic sea ice (MacCracken et al. 2017).
USFWS also determined that future sea ice decline would not threaten walrus survival and we know that walruses have come ashore in the Chukchi Sea during the ice-free season in summer and/or fall for more than 100 years (Crockford 2014; Fischbach et al. 2016).
It all adds up to a non-story although it might work as click-bait for those few readers who eagerly seek out any event blamed on climate change.
Such large herds coming ashore in summer or early fall are a natural phenomenon and a sign of population health, not climate-change-induced catastrophe (Crockford 2014; Lowry 1985).
Dr. Susan Crockford is a University of Victoria (British Columbia, Canada) zoologist who specializes in Holocene mammals, including polar bears and walrus. Her new book is The Polar Bear Catastrophe That Never Happened (Amazon).
Read more and references at Polar Bear Science