“…despite the loss of good denning areas and a shrinking habitat for hunting, Svalbard’s bears seem to be doing fine.…The sea ice season is now several months shorter, and the ice edge typically lies several degrees further north than what was normal 20-40 years ago….Polar bears can survive long periods without food, provided they have accumulated a good fat reserve during the few months in spring and summer when sea ice is present, and seals are abundant.” [Jon Aars, Norwegian Polar Institute, 2018]
Jon Aars from the Norwegian Polar Institute has written an update on the status of Svalbard polar bears for the general public (The Barents Observer, 8 January 2019, republished from a story published by The Fram Centre in their newsletter: Population changes in polar bears: protected, but quickly losing habitat).
Read the whole thing below (original has awesome photos). It reports the truth of the current situation with the usual caveats about what might happen decades into the future. Continue reading
More ice in Hudson Bay and adjacent regions than we’ve seen at this time of year for more than two decades: not since 1993 has there been as much polar bear habitat in the 2nd-last week of November.
The anomaly chart for this week is almost all blue:
Other years back to 1994 had much less ice for the 2nd-last week in November, as the charts below show. Colour charts are only available from 2004.
What’s a good analogy for sea ice as essential polar bear habitat? Biologist Andrew Derocher claims that the soil in a forest is appropriate, because without the soil you can’t have the forest ecosystem. However, that’s a specious comparison because the amount of soil in a forest does not change markedly with the seasons the way that Arctic sea ice does.
A much better analogy is a big pond that dries up a bit every summer. The amount of habitat available to sustain aquatic plants, amphibians and insects is reduced in the dry season but many species have special adaptations for surviving reduced water availability. For the rest of the year, however, the pond provides an abundant and non-limiting habitat for all the creatures and plants that live there.
Posted in Advocacy, Life History, Sea ice habitat
Tagged analogy, ecosystem, extinction, forest, habitat, Interglacials, polar bears, resilience, sea ice, wetlands
Last year, an early freeze-up of Western Hudson Bay sea ice almost ruined the Polar Bear Week campaign devised by Polar Bears International to drum up donation dollars and public sympathy for polar bear conservation. Many bears were on the ice hunting by 7-8 November in 2017 before the celebratory week was done (the average date that bears left the ice in the 1980s): sea ice charts suggest the same may be happening this year.
Ice is forming along the Hudson Bay coast more than a week earlier than it was last year (barely discernible on the map below but detailed ice charts show it clearly), consistent with early build-up of ice in the Canadian Archipelago, East Greenland, and Foxe Basin since mid-September.
The question is: will the ice continue to build over the next few weeks or get blown offshore? See the ice charts below for this year and 2017.
Posted in Life History, Sea ice habitat
Tagged Churchill, freeze-up, gray ice, Hudson Bay, new ice, polar bear alert, polar bears, sea ice, shorefast ice, western hudson bay, winds
Svalbard in the western Barents Sea has recently had less sea ice extent than it had in the 1980s, especially in the west and north, but this is not unprecedented.
New evidence from clams and mussels with temperature-sensitive habitat requirements confirm that warmer temperatures and less sea ice than today existed during the early Holocene period about 10.2–9.2 thousand years ago and between 8.2 and 6.0 thousand years ago (based on radio carbon dates) around Svalbard. Barents Sea polar bears almost certainly survived those previous low-ice periods, as they are doing today, by staying close to the Franz Josef Land Archipelago in the eastern half of the region where sea ice is more persistent.
As this sea ice chart for 18 April 2018 shows, ice this month has been virtually absent from the west and north coasts of the Svalbard Archipelago, while Franz Josef Land to the east is surrounded by highly concentrated pack and land-fast ice.
From a new paper by Jan Mangerud and John Svendsen (2018) [my bold]:
Svalbard, located between 74° and 81°N, is the warmest place on Earth at this latitude (Drange et al., 2013). This is because of the North Atlantic Current and large-scale atmospheric circulation which transport warm water and air masses from lower latitudes northwards across the Atlantic and along the coast of Norway to Svalbard (Figure 1). Yet, during the Holocene Thermal Maximum, the climate of Svalbard was considerably warmer than at present.
The transition from Younger Dryas cold to Holocene Thermal Maximum warm conditions took place very rapidly, according to records from nearby Greenland (Taylor et al. 1997), warming in “steps” of about five years each over a period of about 40 years. This was at least as fast, if not faster than, recent Arctic warming between the 1980s and 2015. And since polar bears of the Barents Sea and adjacent Arctic areas appear to have survived this change to Holocence Thermal Maximum conditions, it challenges the notion that recent warming has been (or will be) too fast to allow polar bears to survive without huge changes in their present distribution (Amstrup et al. 2007).