A new study from the U.S. Geological Survey reveals that greenhouse gas emissions remain the primary threat to polar bear populations. Unfortunately for polar bears, this is the case whether GHG emissions stay at the current rate or if they are reduced to a level that would stabilize climate warming.
Researchers studied predicted population changes of polar bears in four ecoregions under two scenarios. Both scenarios, which consider sea ice changes projected by the Intergovernmental Panel on Climate Change (IPCC), show declining polar bear populations though the end of the century.
“Addressing sea ice loss will require global policy solutions to reduce greenhouse gas emissions and likely be years in the making,” Mike Runge, a USGS research ecologist, said in a news release. “Because carbon emissions accumulate over time, there will be a lag, likely on the order of several decades, between mitigation of emissions and meaningful
stabilization of sea ice loss.”
If GHG emissions remain unabated, polar bear populations in two of the four ecoregions are predicted to reach “a greatly decreased state” 25 years sooner than if emissions are stabilized. If emissions are stabilized, populations in three of the ecoregions are still predicted to decline dramatically.
“Substantial sea ice loss and expected declines in the availability of marine prey that polar bears eat are the most important specific reasons for the increasingly worse outlook for polar bear populations,” said lead author and USGS research biologist Todd Atwood.
The researchers note that the “most optimistic prognosis” for polar bears requires immediate and aggressive reductions of GHG emissions.
To learn more:
- Read the full news release: Greenhouse Gas Emissions Remain the Primary Threat to Polar Bears.
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