Hunting ringed seal, the preferred diet for polar bears, has become a lot more difficult over the past decades for the large white bear. With warmer temperatures in the Arctic, the ice, where the ringed seal feed and give birth, melts earlier. When the polar bears come out of winter hibernation in early spring the ice may already be gone and so are the seals. The polar bear is left starving in a period when it should build up its body fat for the coming birthing period.
This is just one example of how the general increase in global temperatures has an immense effect on the Arctic environment, as described in the recently released United Nations Environment Programme (UNEP)’s Global Environment Outlook report (GEO3).
Measurements from 1979 to 1997 indicate an increase of 1oCelcius per decade in the eastern Arctic and a decrease of –1oCelcius in the western Arctic.
At the same time the protective stratospheric ozone layer has thinned. There have been sporadic episodes of severe stratospheric ozone depletion over the past 30 years and a 7.5 per cent decrease in Arctic ozone between the 1970s and 1990s. For each 1 per cent decrease in stratospheric ozone, there is about a 1 to 2 per cent increase in ultraviolet radiation. The impacts are serious and can affect the entire food chain of the Arctic. For example, reduced ozone protection damages phytoplankton and other microbial organisms that power the life systems of the Arctic.
The warmer temperatures also reduce the snow and ice cover. This, together with increased levels of pol lutants on the land surface, reduce the amount of reflection of sunlight adding to the overall warming effect.
The changes are a stark reminder of the interconnectedness between the earth’s surface, its water masses and its atmospheric systems. According to scientists polluting human activities both in and outside the Arctic contributes to most of these changes.
Most Arctic states embrace the Kyoto Protocol and other climate change instruments, with the exception of the withdrawal of the USA.
For further reading
GEO-3 http://www.grida.no/geo3 AMAP (1977) Arctic Pollution Issues: A State of the Arctic Environment Report
CAFF (1994) The State of Protected Areas in the Circumpolar Arctic http://agdc.usgs.gov/caff/caff_maps.html