Jumping on thin ice
It appears to be International Polar Bear Day…. No clue who made that up (or who actually knows about it…), but a good reason to blog about Polar Bears and their problems…. Often I get asked about the Polar Bear population on Spitsbergen. Is it declining as everybody says? Will Polar Bears become extinct soon? Well… It’s hard to say… First of all it’s really difficult to count Polar Bears. They inhabit one of the most inhospitable habitats on earth and those are (for good reason) places that are hardly inhabited. The last Polar Bear count was from 2004. At that time, the Spitsbergen-Novaya Zemlya-Zemlya Frantsa Iosifa-population was estimated at around 3000 individuals. This is the highest number ever counted for this population. So no problems with climate change here, one could say. Well, the population is still recovering from the extensive hunting that stopped when Polar Bears became protected in 1974. A new count will give more insight in the current state of this population. Worldwide the image is different. Some populations are stable, or even increase, but in other populations (especially the more southern populations) a distinct decrease is observed. On this map you can see the differences per population.
Why do Polar Bears get into trouble with the changing climate? Polar Bears have great home ranges and can roam for many miles in search for food. This food, mostly (ringed) seals, are closely connected to the sea ice. They use it to haul out and they feed on the fish that live underneath the ice. When the ice disappears, the algae that live under the ice disappear. With these algae, also the crustaceans that feed on those algae disappear. With this there is no food for the fish that serve as the main food for the seals. And no seals means no Polar Bears… However, in the area around Spitsbergen there is still quite a lot of sea ice. We notice a distinct drop in sea ice extent in summer, but it’s still there. In summer the extent is low however and the ice is not connected to the land anymore. This means that many bears get stuck on land, without a lot of food and have to survive on their fat reserves. For bears who manage to stay on the ice things still seem ok. Pregnant females however face another problem. They have to be on the ice in summer, to make sure they have enough body reserves tot survive the six months in their snow den, three of which they have to nurse her young. These snow dens are located on steep mountain slopes. As the ice is not connected to the land at the end of summer, they have to swim towards these mountains, using valuable body reserves they need. Because of this, reproduction is a lot lower in recent years. And what will happen if the sea ice in summer is gone completely, as scientist predict to happen within the next 30 years…
So maybe an International Polar Bear Day isn’t such a bad idea at all. One of the suggestions for this day is to turn down your heating a few degrees. More suggestions to save energy (and Polar Bears) can be found here. It’s worth it! More Polar Bear pictures can be found on my website.