One hundred thirty miles north of Nome, a small coastal village on Sarichef Island is feeling the effects of climate change. Shishmaref, Alaska, is falling into the sea. Rising temperatures are melting the permafrost, the layer of frozen ground beneath the surface. Without this firm base, waves have eroded the land on which Shishmaref’s villagers make their home. They must relocate their houses inland or start all over somewhere else.
Nowhere is global warming having as obvious an impact as in the Arctic, and people living in Alaska, northern Canada, northern Scandinavia and Siberia have front-row seats. Some experts say that temperatures in these regions have risen by 3˚ to 5˚F over the past 30 years. And the temperature in the Arctic has warmed at twice the global average rate in the past century, according to the 2007 Intergovernmental Panel on Climate Change (IPCC) report. Permafrost is ground that maintains a temperature below freezing for at least two years. In some areas, that frozen layer is thawing, causing roads to collapse, runways to crack, and homes to sink, split apart, or even fall into the sea. But inside that icy ground is a threat more dangerous than crumbling infrastructure: massive amounts of greenhouse gases that, if released into the atmosphere, have the potential to quickly intensify climate change.
The soil, rock and sediment that make up permafrost are divided into two layers. The top, known as the active layer, runs slightly less than one foot to several feet deep and thaws every summer. The bottom layer remains solid year-round. Thickening of an area’s active layer indicates that the frozen ground beneath it is melting.single page
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