Melting ice threatens polar bears to survival.
The sea ice in the Arctic has shrunk 75 %!
Many people are not aware that if the sea ice disappears, the polar bears disappear. They can not hunt seals on land, and certainly not in the water, where seals are much faster. And without the seals, they starve and die thus the sea ice is a necessity for Polar Bears to survive.
The method a polar bear use to catch a seal is waiting on some sea ice while trying to lurk a seal from one of the seal’s breathing holes. Here the bear sits quietly. Even the slightest movement on the ice will make the seal hear it. When the seal comes up to breathe, the bear slaps it on the head with its giant paw and pulls it up on the ice.
Another strategy the Polar bear uses is to catch seals lying on the edge of the ice sunbathing. Typically, the polar bear dives to the edge and jumps up, surprising the seal. However, that method requires more energy, than luring the seals up from the breathing holes.
Of course, this type of hunting requires ice on the sea. Due to climate change, more and more is melting away. This means that polar bears must swim farther and farther to get to new hunting areas where they can catch seals. Swimming costs are expensive for polar bears. New research shows that polar bears need three to four times as much energy when they swim rather than strolling along the ice. The problem is that the polar bears do not have a lot of energy in excess, as it also becomes harder and harder to obtain food.
In other words, things are really bad for Arctic bears.
Eats five times as much as a grown man a day!
The Polar bear is huge and can live in the cold and desolate regions of the Arctic because it eats very nutritious food. It feeds primarily on the thick layer of fat on ringed seals and belt seals. An adult polar bear should have at least 12.000 calories a day! However, they can easily get them if they only catch one single seal a week. Bacon from a single ringed seal can keep a polar bear going for 11 days. However, it requires that it should not swim too much and can catch the seals at their breathing holes. That hunting method is extremely energy efficient.
Goes ashore in the summer
The polar bear lives in almost the entire Arctic area, but there is a difference in how much sea ice is left in the summer in different areas.
At Hudson Bay in Canada, where a large polar bear population lives, the ice is now melting so early in the year that the bears are spending more and more time on land.
In other areas of the Arctic, they have the choice between either swimming north out into deep water where the ice does not melt or going ashore. Both choices are bad. The deeper the sea, the less nutrition is there and that means fewer seals. And on land, they can not catch the seals at all and have to find other food resources.
On land, the polar bears must starve instead, unless they are lucky enough to find a weak reindeer, some snow-geese eggs or a bunch of berries. It is much harder for them to get enough calories that way – both because there is less energy in the diet and because it requires more energy to provide.
To compare then bacon from one ringed seal corresponds to one and a half reindeer, 37 mountain trout, 216 eggs from snow geese or three million blackberries.
Polar bears that do not have access to seals lose about a kilo a day. It’s really bad for the females, who typically get pregnant in the fall and lie in an ice cave for four months, where they give milk to their cubs and cannot catch food.
Today, there is about 75% less sea ice!
Since the 1980s, much of the polar bears’ vital sea ice has disappeared. Because more of the ice has melted and there is more open sea, a smaller portion of the sun’s rays are reflected back. Instead, the ocean absorbs the sun’s energy. This means that even lower temperatures are needed before the sea freezes, while the temperatures do not have to rise much before the ice begins to thaw. They has let to the sea ice begins to melt earlier and earlier in the year.
And so it goes hard on the polar bears. The number of polar bears in Hudson Bay has dropped by 30% since the 1980s. By the Beaufort Sea off Alaska, the population has fallen by as much as 40%!
In addition, the polar bears that are left are thinner and smaller. The newest generations of polar bears are smaller. Many of them go all summer without getting anything to eat.
The bear at the top of the world
The polar bear is a close relative of the brown bear or grizzly bear, as it is also called.
It is estimated that the polar bear split from the brown bears at least 489,000 years ago. Here the climate was warmer and the brown bear could migrate further north. Some of the bears ventured out on the ice and tried to catch seals. The bears with the lightest furs got an advantage and stayed on the sea ice.
Today, there are about 23,000 polar bears left in the world. Most live in Canada, but they are also found in Greenland, Alaska, Russia and Svalbard.
Climate projections suggest that the summer sea ice around the year 2050 will be completely gone!