Are Polar Bears Starving Because Of Climate Change
Yous've probably seen the news stories lately about a remote Russian town being "invaded" by dozens of hungry, garbage-eating polar bears. These bears are roaming effectually playgrounds, rummaging through the local dump, and fifty-fifty trying to enter function buildings.
A similar incident occurred in 2016, when a sloth of polar bears — yes, that's the proper commonage proper noun — besieged scientists at a research station in the Russian Arctic.
But these news stories don't paint the total motion-picture show of what'due south happening to the iconic white bears as climate change takes hold in the north. Are they all starving? Will polar bears go extinct? Why is sea water ice so important?
The answers to these questions are complex, but we've boiled downwardly the basic facts for you here.
Are polar bears endangered?
Not all the same, but they're non doing great. The IUCN lists the polar bear ( Ursus maritimus ) as a vulnerable species, one pace abroad from existence endangered.
Scientists don't take exact numbers on the polar bear population, because these animals are spread out over a large expanse of rough, inhospitable terrain and are very difficult to count. The best estimate is around 25,000 animals in Canada, the United States, Greenland, Norway, and Russia.
In that location are nineteen unlike subpopulations of polar bears, and depending on where they live, some of these sub-populations are faring amend than others. Some are stable, one is increasing, several are in turn down, and for the residual we just don't have good data.
Recently, a controversial report from the Canadian government said that there are too many polar bears in the Canadian Arctic, threatening the safety of Inuit peoples living there. Many scientists disagreed with those findings, stating that bears might appear more than numerous because they're coming into contact with humans more frequently.
Why is climate change bad for polar bears?
Polar bears should really be chosen ice bears, considering water ice is key to their survival.
The bulk of a polar carry's diet is made up of seals that live on and effectually the edge of the bounding main ice, similar ringed seals and disguised seals. Polar bears chase on the ice, stalking seals as they lounge on icebergs or surface for air at a breathing hole.
The extent of the sea ice changes throughout the year. It reaches its superlative in belatedly wintertime, around the end of March, so shrinks during the warmer summer months. Equally the ice melts, polar bears rely more and more on the fatty stores they built upward during the previous winter. By September the sea ice is at its lowest and bears oftentimes struggle to find enough nutrient. Then as winter comes the ice grows, assuasive polar bears to hunt more hands.
This reliance on sea water ice makes polar bears extremely vulnerable to climate modify. The Arctic is warming faster than most other places on globe, and as it warms in that location's less and less ice. From 1979 to 2011, the amount of sea ice left in September declined by fourteen percent per decade. Sea ice is declining even faster than climate models predict.
Each year the water ice takes longer to form, covers less area, and melts faster. Polar bears accept less time to chase on the water ice and build up fat reserves for summer, and they must survive on those stores for longer equally they wait for the water ice to render. Starvation is a risk, and scientists are also concerned that bears will be less probable to breed and have cubs if they can't detect enough food.
Climate change is the single greatest threat to polar bears. Declining sea ice non simply deprives bears of their hunting grounds, information technology as well exacerbates other threats. Less ice means that more than of the Arctic will be open to oil drilling, commercial shipping, pollution, tourism, and even hunting. These problems already threaten polar bears, and with climate change they volition probable become worse.
Are polar bears starving?
Yes, but not all of them. Not notwithstanding.
Almost a year ago, a video of a starving polar bear transfixed the internet. Shot by photographer Paul Nicklen, the footage showed an emaciated polar bear stumbling about incoherently, hours away from death. Information technology'south impossible to say that climate change acquired this particular bear to starve to decease.
Only equally the sea ice disappears, more and more than bears may endure this fate.
Shrinking water ice ways the polar bears take less time to chase and build up fatty reserves. It as well ways they have to travel farther to notice their next meal, burning more calories and farther depleting their fat stores. Bears may take to swim greater distances between ice packs, which puts petty cubs at risk of drowning.
Polar bears are even more than reliant on a diet of fat-rich seals than scientists previously thought. In one written report, researchers used Fitbit-like activity monitors and GPS collars with cameras to monitor bears' activity and hunting over a viii to 10 day menstruation. They calculated that an adult polar bear needs to eat at least one developed ringed ocean (or three juveniles) every x days. 4 bears in the written report didn't encounter that baseline, and in less than 2 weeks they lost almost 10 per centum of their trunk mass, or about xl pounds.
Unfortunately, hunting dissimilar prey on land isn't enough to feed a hungry bear. In the lean summer months, bear practise supplement their diet with food like caribou, berries, or bird eggs. Only these foods don't accept enough calories to aid bears build up their fat reserves, because bears have to expend more than energy to discover them.
It's worth noting that — at least right now — not all polar bear populations are struggling to find nutrient. Some parts of the Arctic still take year-round pack ice, while other areas are completely water ice-free for several months. Nicklen, the photographer who captured the footage of the starving affect Canada's Baffin Island, told National Geographic that he has seen bears in Russia that are so fat they tin barely walk. It all depends on the ice.
In places where the ice is disappearing fastest, bears are more than and more than likely to come into contact with people. The Russian town of Belushya Guba recently alleged a country of emergency after an influx of more than 50 polar bears descended on the town in search of food. Photos show dozens of adults bears and cubs scavenging in the town's rubbish dump and wandering playgrounds.
So just how many bears are starving right now? We don't know. The Chill is just too remote and too vast to monitor polar bears so closely. Only Nicklen's video and the ongoing invasion in Belushya Guba paint a worrying motion picture of what is to come as the sea water ice slips away.
Will polar bears go extinct?
Mayhap.
There are so many variables at play that scientists can't say for certain if climate change will doom polar bears to extinction. But we exercise know that climate change will drastically and chop-chop reduce the habitat that these bears demand to survive. And that doesn't bode well for bears.
A report on the Canadian Chill Archipelago found that, under business concern-as-usual climate projections, polar bears may face starvation and reproductive failure beyond the region by the year 2100. Studies also show that polar bear populations will become more fragmented as ice declines, threatening their genetic health.
Another possible fate — and threat — is that polar bears will crossbreed with grizzly bears. Grizzly bears are venturing further and further n — likely because of climatic change — bringing them into contact with polar bears.
Polar bears actually evolved from grizzly bears virtually 150,000 years ago, and they can even so breed with this other species successfully. In the past 20 years, scientists and hunters have found a scattering of polar-grizzly hybrids, called "pizzly" or "grolar" bears. While it's non a widespread problem nonetheless, conservationists worry that both hybridization and full general competition with grizzlies could threaten polar bears in the future.
Tin we exercise anything to help?
Unfortunately, there are no quick fixes to save the polar bear.
Some people have raised the idea of relocating bears to Antarctica, or for feeding wild bears to help fight starvation. Both ideas are extremely problematic, expensive, and could cause lasting ecological damage for other species.
At the end of the solar day, these are just temporary solutions — the only way to protect polar bears long-term is to reduce greenhouse gas emissions. (You tin read more about The Nature Salvation'due south efforts to fight climatic change here.)
Source: https://blog.nature.org/science/2013/12/03/what-science-polar-bear/
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