No Safe Haven for Polar Bears in Warming Arctic
By Tim Radford
The world of the polar bear is shrinking—everywhere. New research by scientists in the U.S. confirms that each of the 19 known populations of Ursus maritimus is increasingly affected by the earlier sea ice melt in the Arctic spring, and the later arrival of ice every autumn.
Polar bears are affected by the earlier sea ice melt in the Arctic spring.Alamy
The finding is hardly a shock, as there have been warnings from conservationists about such things for years, with the polar bear becoming an icon of climate change concerns. And in most cases of species threat there are winners as well as losers.
The 25,000 or so surviving Arctic bears rely on the ice for their feeding and breeding success. A few stay on the ice all year round, but southerly populations survive ashore in the summer, and it is the seasonal winter feast upon seals and other sea mammals that gives them the nourishment to make it to the next breeding season.
"Sea ice really is their platform for life," said Kristin Laidre, principal scientist at the University of Washington's Polar Science Centre (PSC). "They are capable of existing on land for part of the year, but the sea ice is where they obtain their main prey."
She and her co-author, Harry Stern, principal mathematician at the PSC, used 35 years of satellite data to examine sea ice concentrations around the entire Arctic.
The total number of ice-covered days fell at the rate of seven to 19 days per decade between 1979 and 2014. Sea ice in the summer months—when polar bears are often forced to fast on land—also declined in all regions, by between 1 percent and 9 percent per decade.
And they found that the trend towards an earlier spring melt and a later autumn freeze was consistent everywhere.
Dr. Laidre and other scientists reported last year that all Arctic marine mammals could be at risk because of habitat loss. The catch was that biologists did not know enough about them to be sure.
Another group of researchers has established that things look bleak for Canada's polar bears, but this is just a subset of the species.
The PSC scientists have now established that spring melt has begun on average three to nine days earlier per decade, and the freeze similarly later each decade. Effectively, that added up to seven weeks' total loss of good habitat—that is, firm ice upon which the bears can stalk seals.
"These spring and fall transitions bound the period when there is good ice habitat available for bears to feed," Dr Laidre said. "Those periods are also tied to the breeding season, when bears find mates, and when females come out of their maternity dens with very small cubs and haven't eaten for months.
"We expect that if the trends continue, compared with today, polar bears will experience another six to seven weeks of ice-free periods by mid-century."
By Stacy Malkan
Neil deGrasse Tyson has inspired millions of people to care about science and imagine themselves as participants in the scientific process. What a hopeful sign it is to see young girls wearing t-shirts emblazoned with the words, "Forget princess, I want to be an astrophysicist."
As Trevor Noah noted during The Daily Show episode last night (starts at 2:25), the real reason Trump has these rallies is to "get back in front of his loyal crowds and feed of their energy." Noah believes that "Trump supporters are so on board with their dude he can say anything and they'll come along for the ride."
By Katie O'Reilly
Two years ago—long before coal became one of the most dominant and controversial symbols of the 2016 presidential election—Bloomberg Philanthropies approached production company RadicalMedia with the idea of creating a documentary exploring the U.S. coal mining industry. Last spring, they brought on Emmy-nominated director Michael Bonfiglio, tasked with forging a compelling story out of the multitudes of facts, statistics and narratives underlying the declining industry.
The Sierra Club released a new analysis Friday that found that transitioning all 1,400+ U.S. Conference of Mayors member-cities to 100 percent clean and renewable electricity will significantly reduce electric sector carbon pollution nationwide and help the U.S. towards meeting the goals of the Paris climate agreement.
Watch above as Newsy explains that the decision comes despite serious concerns from the environmental and scientific community, and Tribal Nations about a declining, isolated grizzly bear population with diminishing food resources and record-high mortalities.
By Francine Kershaw
Seismic airguns exploding in the ocean in search for oil and gas have devastating impacts on zooplankton, which are critical food sources for marine mammals, according to a new study in Nature. The blasting decimates one of the ocean's most vital groups of organisms over huge areas and may disrupt entire ecosystems.
And this devastating news comes on the heels of the National Marine Fisheries Service's proposal to authorize more than 90,000 miles of active seismic blasting. Based on the results of this study, the affected area would be approximately 135,000 square miles.
By Jill Richardson
Is coconut oil:
- good for you
- bad for you
- neither good nor bad
- scientists don't know
The subject of this question is the source of a disagreement. Initially, the question was thought to be settled decades ago, when scientist Ancel Keys declared all saturated fats unhealthy. Coconut oil, which is solid at room temperature, is a saturated fat.