It seems inevitable. What is happening to these animals? What is the cause of the decline of the polar bear in the world? Apparently, it is directly related to the emission of greenhouse gases (GHG).
The report was published in the journal ‘Science’. It connects the dots between greenhouse gas emissions, the number of ice-free days caused by specific amounts of emissions, and polar bear survival rates. It also explains recent downward trends observed in their population.
Polar bears were listed under the Endangered Species Act (ESA) in 2008. It was done because of the loss of sea ice caused by global warming. But it was said ESA considerations on emissions would not be necessary. They would only include them if this specific impact could be separated from all historical global emissions.
“We have known this for decades. Continued warming and loss of sea ice reduces the distribution and abundance of polar bears.” Lead author Steven Amstrup, Ph.D., assistant professor at the University of Wyoming, recalls in a statement. “But we couldn’t distinguish the impact of greenhouse gases emitted by specific activities. Now we can.
The methodology used allows us, for the first time, to analyze the impact of emissions according to their origin. “And it has wide application beyond polar bears to other ecosystems and species. It could be used by managers and policy makers around the world. It would be vital when evaluating development projects.”
This was based on the basis established in a 2020 report. It related the predicted survival of polar bears to the duration of summer fasting caused by global warming. This paper goes a step further. It quantifies the number of ice-free/fasting days caused by a specific amount of equivalent CO2 emissions. It allows a direct calculation of the impact of a project’s emissions on future polar bear cub recruitment. And it explains the global polar bear decline.