Bleak out­look for polar bear numbers in Arc­tic ice study

China Daily (Hong Kong) - - WORLD - By REUTERS

Ris­ing tem­per­a­tures that melt sea ice in the Arc­tic will prob­a­bly re­duce the polar bear pop­u­la­tion by a third over the next few decades, and the same warm­ing trend is likely to worsen the de­cline of wild rein­deer, sci­en­tists said on Mon­day.

The new find­ings by uni­ver­sity and govern­ment re­searchers were pre­sented as part of a panel dis­cus­sion about cli­mate im­pacts on wildlife dur­ing a meet­ing of the Amer­i­can Geo­phys­i­cal Union in San Fran­cisco. The pre­sen­ta­tion was streamed live on the in­ter­net.

The polar bear re­search is drawn from new satel­lite data doc­u­ment­ing a loss of Arc­tic sea ice — the an­i­mal’s chief habi­tat — from 1979 to 2015, and form­ing the ba­sis of pro­jec­tions in fur­ther de­clines of both ice and bears over the com­ing decades.

Polar bears cur­rently num­ber about 26,000, but their pop­u­la­tion is ex­pected to di­min­ish by some 8,600 an­i­mals over the next 35 to 40 years, the sci­en­tists said. At the time polar bears were de­clared a threat­ened species in 2008, one study pre­dicted they could van­ish from two-thirds of their na­tive range by mid­cen­tury.

The lat­est data bet­ter quan­ti­fies such an out­come.

“There is the po­ten­tial for a large re­duc­tion in the global pop­u­la­tion of polar bears over the next three gen­er­a­tions if the sea ice loss con­tin­ues at the rate we’ve seen it,” said Kristin Laidre, a marine mam­mal ecol­o­gist at the Uni­ver­sity of Wash­ing­ton’s Polar Science Cen­ter.

Polar bears, stand­ing as tall as 3.35 me­ters and weigh­ing up to 635 kilo­grams, use float­ing sea ice as plat­forms for ev­ery­thing from mat­ing and rear­ing their young to hunt­ing their pre­ferred prey of ringed seals.

The study was led by the US Fish and Wildlife Ser­vice’s Eric Regehr, who told Reuters habi­tat loss was un­equiv­o­cal but that ef­fects have var­ied among the world’s 19 sub­pop­u­la­tions of polar bears, whose range lies mainly within the Arc­tic Cir­cle.

He pointed to a re­gion north of Alaska where the num­ber has dropped sharply amid sig­nif­i­cant sea ice losses. An­other pop­u­la­tion west of Alaska ap­pears to have ex­pe­ri­enced less im­pact, but that area may sus­tain larger, health­ier pop­u­la­tions of seals and other polar bear prey, Regehr said.

A warmer cli­mate also is thought to be a pri­mary cul­prit in the rapid de­cline of wild rein­deer and their close cousins, cari­bou, An­drey Petrov, head of the Arc­tic Cen­ter at the Uni­ver­sity of North­ern Iowa, said at Mon­day’s sym­po­sium.

Petrov’s study of rein­deer in Taimyr in north­ern Rus­sia shows the herd’s pop­u­la­tion has fallen to about 600,000, from 1 mil­lion in 2000.

There is the po­ten­tial for a large re­duc­tion in the global pop­u­la­tion of polar bears.” Kristin Laidre, marine mam­mal ecol­o­gist

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