Loss of sea ice due to climate change will have a strong impact on a global scale on the number of polar bears. According to a new study, by mid-century polar bear population could decrease by more than 30 per cent.
Researchers found that the mean global polar bear population size will decrease by more than one-third over the next 34-41 years, a period the authors describe as “three polar bear generations.” There is a 71% likelihood for this prediction to materialize, based on mathematical models used by researchers to predict the effect climate change will have on sea ice in the future.
“Anthropogenic climate change is the primary threat to the species because, over the long term, global temperatures will increase and Arctic sea ice will decrease as long as atmospheric greenhouse gas concentrations continue to rise. The global population of approximately 26 000 polar bears is divided into 19 subpopulations, which are grouped into four ecoregions reflecting sea-ice dynamics and polar bear life history. The subpopulations currently exhibit variable status relative to climate change. Two have already experienced sea-ice-related demographic declines. Others show signs of nutritional stress, have been reported as stable or productive or have unknown status owing to deficient data”, reads the report.
The authors of the study said that these findings will lead to the listing of these species as “vulnerable” according to the International Union for Conservation of Nature (ICUN) Red List of Threatened Species.
“The one problem I’ve got is that it’s probably overly optimistic. If we look at 2016 for sea ice, it was a lot worse than anything else we’ve seen in the record. Even the sea ice we’ve seen for November, this past month, the results are dramatically different than the longer term projections… I think the actual conditions for polar bears may be worse than this paper puts forward”, told University of Alberta bear biologist Andrew Derocher of the study, according to cbc.ca.
“We’ve done a fair bit of work to indicate that just one or two bad years in an area can have devastating effects on a population,” he added.
Derocher also said that the concern for some of the subpopulations is reaching a critical juncture, particularly within some parts of Canada.
“Research we’ve done with the Hudson’s Bay population suggests very clearly that we likely will not have polar bears in that area by mid-century… It’s also very unlikely bears with persist in the southern Beaufort past that time”, he concluded.