New fears on sea-level rise

new cubs. Previous research has already shown that unstable ice can result in failures of on-ice denning attempts. Less ice than is suitable for denning apparently has led to an increased frequency of pregnant polar bears in this region choosing to den on land, " says Fischbach. Unlike other temperate and Arctic bear species that hibernate during winter months, polar bears remain active and seals are available on the pack ice throughout the winter. Pregnant females must, however, create a den for themselves and their cubs to protect them from the harshness of the Arctic winter – they give birth in midwinter. Throughout most of their range, pregnant polar bears have created dens mostly on land. But in northern Alaska, many polar bears historically have given birth on sea ice, sometimes as much as 600 kilometres offshore. If declines in sea ice continue, the researchers expect that the proportion of polar bears creating dens in coastal areas will continue to increase until the time when the autumn ice retreats so far from the shore to prohibit offshore pregnant females from being able to swim to the Alaskan coast. " Right now " , says Amstrup, " pregnant females foraging offshore in summer must wait up to a month longer than they did even 10 years ago for new sea ice to form so that they can travel to denning areas on land. Alternatively, they must swim even greater expanses of open water to reach suitable land... or they must den on ice that may be stable enough to survive the winter. " USGS researchers have earlier reported declines in the physical stature of adult male polar bears and cubs in the Beaufort Sea region, as well as a decrease in the survival of cubs. The researchers believe that feeding opportunities, like breeding sites, have declined in recent years.This information is being submitted to the US Fish and Wildlife Service as it considers the proposed listing of the polar bear as endangered. Countries based on coral atolls have led the fears about rising sea levels but the issue of global warming, which is contributing to rises in sea level, is out of their hands and in those of the major industrial nations. But this is not stopping growing alarm amongst such island states, some of which rise only a few metres above mean sea level. In Tuvalu in the southern Pacific, …