Experts said emissions remain the primary threat to polar bear populations across the globe, with populations expected to plummet 25 years sooner than previously thought.
Researchers used two models to look at how emissions will affect polar bears. In one, emissions remain on their current course resulting in global warming by the end of the century while the other involved reducing emissions and a stabilisation of warming.
In the unabated emissions scenario, sea ice loss and climate change-related problems would lead to polar bear populations in two of the four ecoregions to reach a massively decreased state 25 years faster than the reduced emissions scenario.
However, both scenarios predicted a worsening outcome for polar bears by the end of the century. If emissions are reduced, the USGS predicts all polar bear populations will decrease except for those found in Archipelago Ecoregion, in the high-latitude Canadian Arctic, where sea ice remains for longer into the summer.
Mike Runge, a USGS research ecologist, said: “Addressing sea ice loss will require global policy solutions to reduce greenhouse gas emissions and likely be years in the making. Because carbon emissions accumulate over time, there will be a lag, likely on the order of several decades, between mitigation of emissions and meaningful stabilisation of sea ice loss.”
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