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Climate Change Could Drive Polar Bears to Extinction by 2100

VOA News

   A studyof the Arcticsayspolar bears are one of the most threatened
   species on earth because ofmelting sea icecaused by climate change,and
   withoutaggressive steps,theanimalscouldbeextinct by the end of the
   century.

   TheUniversity of Torontostudy, published Monday in the journalNature
   Climate Change, says thatpolarbears rely on sea ice to reach their
   prey,usually seals and other water mammals.Researcherswho conducted the
   studysaya loss of ice will force the animals onto land, where they must
   rely on fat reserves due to a lack of food.

   Co-author ofareporton the studyStevenAmstrupsaysthe
   bearscurrentlyhaveless time to feed and a longer time to waituntilthe
   icereturns.He says typically, the ice melts in the early
   summerandmidsummer and returns in fall. "That period when the ice is
   absent is getting ever longer and the bears are facing that longer
   period with less fat on board."

   Modelling was used to determine polar bears' energy requirements while
   fasting and the thresholds that would limit their survival, alongside a
   model predicting the future number of days without ice.

   The researchers used thatto estimate when the survival thresholds would
   be surpassed for13Arctic sub-populations that represent 80% of all
   polar bears.

   Under a high greenhouse gas emissions scenario, the researchers found
   the bears' survival would be "unlikely" in much of the Arctic due to
   reduced sea ice.

   Butthe study maintains that ifthere was a "moderate emissions scenario"
   more sub-populations could survivethroughthis century.

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