A new paper that combines paleoclimatology data for the last 56 million years with molecular genetic evidence concludes there were no biological extinctions [of Arctic marine animals] over the last 1.5M years despite profound Arctic sea ice changes that included ice-free summers: polar bears, seals, walrus and other species successfully adapted to habitat changes that exceeded those predicted by USGS and US Fish and Wildlife polar bear biologists over the next 100 years.
Cronin, T. M. and Cronin, M.A. 2015. Biological response to climate change in the Arctic Ocean: the view from the past. Arktos 1:1-18 [Open access] http://link.springer.com/article/10.1007/s41063-015-0019-3
Thomas Cronin is a USGS paleoclimatologist at the Eastern Geology and Paleoclimate Science Center, and Matthew Cronin is a molecular geneticist at the University of Alaska Fairbanks (see previous posts here and here about Matt’s work on the genetics of polar bear evolution).
From the Abstract:
Arctic climatic extremes include 25°C hyperthermal periods during the Paleocene-Eocene (56–46 million years ago, Ma), Quaternary glacial periods when thick ice shelves and sea ice cover rendered the Arctic Ocean nearly uninhabitable, seasonally sea-ice-free interglacials and abrupt climate reversals.
The final discussion and two summary graphics from this paper (copied below) are especially useful:
Posted in Evolution, Sea ice habitat, Summary
Tagged adaptation, Arctic, arctic seals, biological responses, climate change, climate extremes, Cronin, evolution, facts, genetics, glacial, he, ice-free summer, information, interglacial, LGM, marine mammals, paleoclimate, polar bear, resilience, sea ice, USGS, walrus
A cross-Arctic comparison shows that the US has been the most aggressive in designating polar bears and their main prey species as ‘threatened with extinction’ due to the predicted effects of human-caused (“anthropogenic”) global warming (AGW), even though the US has the least amount of sea ice habit of all circumpolar nations.
I’ve made a chart listing the conservation status of these species across all Arctic nations (Canada, Russia, Norway, Denmark (for Greenland) and the USA), as well as the one international body that considers the conservation status of all species (International Union for Conservation of Nature, IUCN).
Oddly, the IUCN considers the polar bear vulnerable due to future threats from predicted sea ice losses but not ringed seals or bearded seals. This situation highlights the capricious nature of the use of “future threats” (almost exclusively based on predictions of AGW) as a valid criteria for evaluating the conservation status of Arctic marine mammals. It also suggests why the IUCN has tightened considerably its rules regarding this practice.
Posted in Conservation Status, Summary
Tagged AGW, Arctic nations, arctic seals, bearded seal, conservation, global warming, IUCN, North Pole, polar bear, Polar Bear Specialist Group, ringed seal, threatened with extinction, walrus
Previously, I highlighted new research results that showed, contrary to expectations, polar bears in the Chukchi Sea subpopulation are doing better – despite declines in extent of September sea ice – since the 1970s. So it might not come as much of a surprise to find that the same is true for the primary prey of polar bears in the Chukchi and Bering Seas, Arctic ringed seals (Phoca hispida hispida).
Surprisingly, less than 6 months after Arctic ringed seals were placed on the American list of “threatened” species (under the ESA, see previous post here), actual research in Alaska has shown that declines in sea ice have proven better for ringed seals, not worse.
At a presentation given at the Lowell Wakefield Fisheries Symposium in March (Anchorage, Alaska) [program and links to pdfs here] Justin Crawford, a biologist with the Alaska Department of Fish and Game (ADF&G) presented the results of ringed seal research conducted by himself and fellow ADF&G biologist Lori Quakenbush in the Chukchi and Bering Seas (posted online by the event organizers, see references below).
As for polar bears, the Crawford and Quakenbush presentation provides some very interesting details on the status of Chukchi and Bering Sea ringed seals over the last 40 years, and contains some mighty “inconvenient” conclusions that should raise some eyebrows.
I’ve summarized these details and conclusions below in point form, with a map.
Posted in Conservation Status, Life History, Sea ice habitat
Tagged ADF&G, arctic seals, Bering Sea, body condition, Chukchi, ESA, Justin Crawford, Kelly, Lori Quakenbush, lowell wakefield, Phoca hispida, resilient, ringed seals, sea ice declines, sea ice extent, snow cover, summer ice minimum, threatened species, winter ice maximum