Who are the Brooklyn Centre Naturalists?
In 2007, a group of neighbors and business owners who shared a common belief that gardening is a way to foster community and create bonds between neighbors formed Brooklyn Centre Naturalists (BCN).
The trading of plants in a community builds connections that are not easily broken. As BCN continued to meet, we discovered that another bond held us together - the belief that the health of a community depends on the health of its environment.
With that thought in mind, our connection to the National Wildlife Foundation became clear. One of our members researched what it takes to become a registered National Wildlife Community, and the group decided that the designation was achievable.
A community Wildlife Habitat is a designated area that promotes and fosters the vigor and diversity of native birds and animals by providing four basic elements: food, water, shelter and a place to raise young throughout the community. BCB has been registered since the fall of 2008, and we are now working to become a certified habitat.
Q: How does climate change affect polar bears?
A: Climate change, or the current trend of our warming Earth, is causing the sea ice to melt. Polar bears spend their lives on sea ice, hunting seals, their main source of prey. As the extent of sea ice decreases, polar bears lose their hunting platform, forcing them to go ashore and fast, or swim in between ice floes to continue hunting. As the Earth continues to warm, the sea ice continues to melt, making each year a bit more difficult for polar bears to survive.
Q: What exactly is happening to the arctic sea ice?
A: It is melting, shrinking in thickness and extent of coverage. Satellite imagery shows reduced sea ice extent in all seasons, but most significantly in the summer season. Satellite data reveals the remaining ice has lost thickness. According to satellite data provided from the 1970’s to the present time, scientists learned that the arctic ocean was covered mostly with multi-year ice, with young ice just on the edges. Current images reveal that over 40% of the multi-year ice is gone. We lost enough multi-year ice to cover the state of Alaska! This is important because young ice is much more sensitive to environmental changes than multi-year ice. As the warming trend continues, the young ice will likely be susceptible and melt quickly.
Q: Can polar bears adapt to living without sea ice?
A: No one can say for sure. As fast as the ice is melting, polar bears would have to adapt very quickly. Polar bears are large-bodied carnivores, which means that they require relatively large sized prey to stay alive. Seals have become the staple of their diet. Polar bears have the most success hunting seals at breathing holes in the ice, or catching pups in their dens. Seals easily out-swim polar bears, which makes swimming after them an unlikely and probably unsuccessful hunting tactic.
Other Interesting Facts about Polar Bears
- Arctic air temperature is rising at almost twice the rate as the global air temperature due to reduced sea ice cover. Scientists observed this increased rate over the past two decades.
- Loss of arctic sea ice alters oceanic and atmospheric circulation, affecting weather patterns across the globe.
- Polar Bears Need sea Ice to hunt seals
- Polar bears are classified as marine mammals because they spend most of their life on the sea. They do swim, but usually they remain on top of the sea ice, just diving into the water for a quick grab at a seal or to swim from one ice floe to the next. Polar bears tend to come to land only for denning and birthing cubs. Even then some females prefer to form dens on the sea ice itself and avoid land altogether.
- Polar bears are carnivores and eat mostly seals. They have adapted to hunting seals from sea ice. They are particularly good at catching seal pups in ice dens or seals at breathing holes. Once the polar bear is in the water, the seal has a distinct advantage. The seal can easily swim out of the polar bear’s reach, making swimming for seals not a good option for a hungry polar bear. In order to catch seals successfully, polar bears need ice.
- Large mammals such as beluga whales and walruses supplement the polar bear’s diet, but they are much more difficult to kill and can require the effort of more than one bear. Smaller animals, such as ptarmigan or lemmings, can provide some calories, but will do little to help the polar bear survive and maintain its large body size. Polar bears need seals to survive.
- Scientists are finding that polar bears are shrinking, in number and in size. Ice free oceans are particularly hard on cubs and older bears. Sometimes females won’t even produce cubs due to poor body condition. Average litter size has shrunk down to just one cub, maybe two, very rarely three. Scientists are finding that bears seem to be an inch shorter in length on average than they used to be, and they are seeing more underweight bears than ever before. Polar bears are struggling.
- For the first time on record, both the Northeast and Northwest passages were open in 2008, indicating that the arctic sea ice had pulled far away from the coastal edge.
For more information about polar bears, climate change, and what you can do to help, visit www.polarbearsinternational.org