A new report from the U.S. Geological Survey (2015) paints a grim picture for the future of polar bears. Forced onto land as their icy habitats melt, polar bears will be unable to thrive on terrestrial food, such as berries and birds.
Polar bears have one of the fattiest diets of any species, and the high-protein, low-fat food available on land is no match for the ice seals upon which polar bears have been preying for generations. Furthermore, a polar bear would be unlikely to gather enough terrestrial food for long-term survival thanks to competition from grizzly bears.
"The smaller size and low population density of grizzly bears in the Arctic provides a clear indication of the nutritional limitations of onshore habitats for supporting large bodied polar bears in meaningful numbers," said Dr. Karyn Rode.
The world’s sea ice hits a record low for January as the annual melting period expanded according to the National Snow and Ice Data Center. The 5.04 million square miles of sea ice in the Arctic was 524,000 sq miles less than the average 1981-2010 cover. It is the lowest recorded since satellite records began.
Eric Holthause, writing for Grist, has a good read on yet another miserable milestone falling.
Holthause notes that the loss of sea ice is bad news for the biosphere. But the rate of change is even more worrying. He writes; “Global temperatures are rising at a rate far in excess of anything seen in recent Earth history. That means, in all likelihood, these latest records were made to be broken”.
That worrying development is just the latest sign that rising temperatures are inflicting lasting changes on the coldest corners of the globe. The new record low comes as the planet’s climate system shifts further from the relatively stable period that helped give rise to cities, commerce, and the way we live now.
So far, the new year has been remarkably warm on both poles. The past 30 days have averaged more than 21 degrees Fahrenheit warmer than normal in Svalbard, Norway — the northernmost permanently inhabited place in the world. Last month, a tanker ship completed the first wintertime crossing of the Arctic Ocean without the assistance of an icebreaker. Down south in the Antarctic, sea ice is all but gone for the third straight year as summer winds to a close.
The loss of Earth’s polar sea ice has long been considered one of the most important tipping points as the planet warms. That’s because as the bright white ice melts, it exposes less-reflective ocean water, which more easily absorbs heat. And that, sorry to say, kicks off a new cycle of further warming.
According to research published last fall, that cycle appears to be the primary driver of ice melt in the Arctic, effectively marking the beginning of the end of permanent ice cover there. The wide-ranging consequences of this transition, such as more extreme weather and ecosystem shifts, are already being felt far beyond the Arctic.
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