As the Arctic continues to warm because of human-caused climate change, polar bears are spending more time fasting and scavenging in garbage dumps, instead of hunting for seals on sea ice. And as human activity in northern communities increases, the hungry bears’ growing reliance on trash is leading to more human-bear conflict—often to the detriment of one of both species—according to a new paper published in the journal Oryx on Wednesday.
An international team of scientists is sounding the alarm about the harmful effects of human food and waste on polar bear populations, which are already vulnerable because of rising temperatures. In the paper, the researchers share cautionary tales from six communities that have experienced negative food-related interactions between humans and polar bears in Canada, Russia, Alaska and Norway, including incidents that resulted in polar bear and human deaths.
"Already we've had a couple human fatalities in the eastern Canadian Arctic," Andrew Derocher, a biologist at the University of Alberta and one of the paper’s authors, tells Reuters’ Gloria Dickie. "It's surprising just how many places that never had polar bear problems are now having emerging issues.”
Though researchers have long studied food- and trash-related issues among black and brown bears, which regularly make headlines for breaking into homes and vehicles in search of snacks, the paper’s authors say this is the first broad analysis of the issue among polar bears. That’s largely because polar bears haven’t historically scavenged through trash, until more recently.
Polar bears spend much of the year wandering around on sea ice looking for seals, their main source of food. But scientists say the Arctic Ocean is warming four times faster than the rest of the world and, as a result, Arctic sea ice is melting earlier each spring and forming later each fall. This, in turn, means the bears are going hungry for longer and longer periods of time. In some cases, it’s pushing them toward starvation.
With less sea ice, the bears are spending more time on land. And because of their curious, resourceful nature, they’re finding their way to garbage dumps, a trend that is dangerous for both bears and humans. When they scrounge through trash in search of food, the bears are likely also ingesting plastic food wrappers, wood, metal and other harmful inedible materials, as well as potentially toxic chemicals, which can make them sick or even cause fatal blockages.
"At some point, they're going to get hungry and they're going to look for food,” Geoff York, senior director of conservation at Polar Bears International and one of the paper’s authors, tells the CBC. “And if they can smell something that smells like food to them, they don't know that it might well have other things that are negative for their health.”
Beyond that, wildlife managers sometimes euthanize bears because of public safety concerns.
Scientists are also concerned because young cubs still under the care of their mothers are learning that garbage is an easy source of calories.
The situation will likely get worse, unless governments take steps to improve waste management, such as by installing fences, doing more public outreach and education, burning garbage, distributing bear-resistant trash cans, monitoring landfills and using tools to haze and deter the bears, according to the researchers.
But dealing with trash has historically been a challenge for remote northern communities, where the ground is often too frozen to bury trash and trucking the garbage out is expensive.
Still, the researchers urged swift action, as food-related polar bear issues can quickly spiral out of control. Bears remember where they find food and will return again and again, often in greater numbers. In addition, human populations in the north are also growing, which will also mean more trash.
The good news is that when access to food waste and garbage is cut off, other types of bears have returned to their natural feeding strategies. Researchers believe the same will be true for polar bears. Communities already have the tools and knowledge to address the problem—now, they just need to take action.
“Problems of food-conditioning in polar bears have been reported in every country where polar bears exist,” Megan Owen, vice president of conservation science at the San Diego Zoo Wildlife Alliance and one of the paper’s authors, says in a statement. “While each community’s solution may differ, we know that we already have the technology and solutions to solve the problem of human waste attracting polar bears. We need immediate and concerted efforts throughout the Arctic to apply solutions.”