© Kt Miller/Polar Bears International
7/1/2015 5:03:44 PM
Greenhouse Gas Emissions Still Primary Threat to Polar Bear
Greenhouse gas emissions remain the primary threat to the preservation of polar bear populations worldwide, according to a press release from the U.S. Geological Survey.
This conclusion holds true whether greenhouse gas emissions are reduced and climate warming stabilizes, or if emissions and warming continue at the current pace, according to updated USGS research models.
Under both scenarios, the outcome for the worldwide polar bear population will very likely worsen over time through the end of the century. The prognosis is most optimistic through immediate and aggressive greenhouse gas reductions that would limit global warming to less than 2°C above preindustrial levels.
"Addressing sea ice loss will require global policy solutions to reduce greenhouse gas emissions and likely be years in the making," said Mike Runge, a USGS research ecologist. "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."
The updated forecast for polar bears was developed by the USGS with collaborators from the U.S. Forest Service and our chief scientist, Dr. Steven Amstrup. The forecast is being shared in advance of the draft version of the USFWS Polar Bear Conservation Plan, which is expected to be released later this week.
The forecast is an update of the model that Amstrup and his team originally developed in 2007 during his tenure as Polar Bear Project Leader for the USGS, later updated for his Nature paper in 2010.
The original model predicted that we could lose two-thirds of the world's polar bears by mid-century without action on climate change. This prediction was included in the series of reports that led to the listing of the polar bear as a threatened species under the Endangered Species Act.
"Although the model nodes are defined differently than in my original, the outcomes are the same. That is, there is basically no long-term conservation of polar bears without stopping the rise in greenhouse gases," Amstrup said.