Polar bears could become extinct faster than was feared, study says
Source: The Guardian
Polar bears could become extinct faster than was feared, study says
The animals facing an increasing struggle to find enough food to survive as climate change steadily transforms their environment
Oliver Milman in New York
Thu 1 Feb 2018 19.00 GMT
Polar bears could be sliding towards extinction faster than previously feared, with the animals facing an increasing struggle to find enough food to survive as climate change steadily transforms their environment.
New research has unearthed fresh insights into polar bear habits, revealing that the Arctic predators have far higher metabolisms than previously thought. This means they need more prey, primarily seals, to meet their energy demands at a time when receding sea ice is making hunting increasingly difficult for the animals.
A study of nine polar bears over a three-year period by the US Geological Survey and UC Santa Cruz found that the animals require at least one adult, or three juvenile, ringed seals every 10 days to sustain them. Five of the nine bears were unable to achieve this during the research, resulting in plummeting body weight – as much as 20kg during a 10-day study period.
“We found a feast and famine lifestyle – if they missed out on seals it had a pretty dramatic effect on them,” said Anthony Pagano, a USGS biologist who led the research, published in Science.
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Read more: https://www.theguardian.com/us-news/2018/feb/01/polar-bears-climate-change
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Source: Science
Out of balance in the Arctic
John P. Whiteman
Department of Biology, University of New Mexico, Albuquerque, NM 87131, USA.
Science 02 Feb 2018:
Vol. 359, Issue 6375, pp. 514-515
DOI: 10.1126/science.aar6723
Summary
As human activities lead to rising greenhouse gas concentrations in Earth's atmosphere, less incoming solar energy is released back into space, causing a net energy gain that increases global temperatures. The consequence of climate change for polar bears can likewise be understood in terms of an energy imbalance. Sea ice melting reduces the opportunities for polar bears to capture seals (see the photo), leaving them at risk of expending more energy in the pursuit of food than they can obtain. The magnitude of this imbalance is determined by their rate of energy use. On page 568 of this issue, Pagano et al. (1) quantify the energy expense of wild polar bears and show that it is higher than previously estimated.
http://science.sciencemag.org/content/359/6375/514
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