Over the last 150 years, the average temperature of the Baltic Sea Basin has been rising at a rate of 0.14 degrees Fahrenheit per decade, which is slightly higher that the global trend of 0.09 degrees Fahrenheit per decade. This temperature increase has been most acutely felt during the winter, as the number of extremely cold days has decreased. The last ten winters have all been average or mild. One effect of this warming has been a change in the duration and thickness of the Sea’s winter ice cover. Over the last century, the length of the sea ice season has fallen by between 14 and 44 days. This reduction in ice has been linked to a decrease in the population of the endangered ringed seal, which, until this winter, appeared to be recovering after a century of over-hunting and pollution. The species nurses its young in ice lairs, and seal pups are dependent upon maternal care for about 40 days after birth. During this period, they grow in size and build up a layer of blubber, which protects them from the frigid waters. This winter has been the Basin’s warmest in almost 300 years, and the already retreating ice has exposed many of the ice lairs, which means that the pups have not had 40 days to prepare for the Sea. Few of the pups that were born this winter are expected to survive.(Sources: The Helsinki Commission: “Climate Change in the Baltic Sea Area.” Baltic Sea Environmental Proceedings No. 111 (2007). Accessed Online 12 March 2008
No comments:
Post a Comment