100 Places To Remember: North Slope, Alaska, USA
Geschreven op 16-2-2010 - Erik van Erne. Geplaatst in Natuur
A Vulnerable Area of Thawing Permafrost. The North Slope region consists of a huge expanse of permafrost in the most northerly part of Alaska. Forest and tundra cover the region, with winding rivers running from the Brooks Ranges to the Beaufort Sea in the Arctic Ocean. Despite being almost as big as Great Britain, the permanent population numbers a mere 7,300.
As well as magnificent scenery and wildlife, including caribou, polar bear and arctic fox, the North Slope is also home to the biggest oilfield in North America. Five thousand migrant workers are employed at Prudhoe Bay on the rim of the Beaufort Sea, producing 650,000 barrels of oil a day. From Prudhoe Bay, the Trans-Alaskan Pipeline transports the oil across the Alaskan state to the Port of Valdez in the south.
The thawing of the permafrost now poses a serious threat to the area. The active layer of permafrost the part that freezes in winter, thaws in summer and sustains vegetation ranges from a few inches to a few feet deep. In the last quarter of a century, rising temperatures have made the active layer deeper. It now encroaches into the permanently frozen deposits of ice, soil, stones and organic material that form the foundation for the physical stability of the whole area.
A further increase in temperature due to global warming is expected to make the active layer even deeper and slowly dissolve the permanently frozen soil. If this happens, it would gradually undermine the forests as well as man-made structures.
As the deeper layers of permafrost thaw, organic material that has been frozen for millennia will thaw too, potentially releasing greenhouse gases into the atmosphere and further fuelling climate change.
