Since the mid-20th century, Alaska has warmed 3 degrees Fahrenheit and its winters have warmed almost 6 degrees. The predictions are even more dire. By the end of the 21st century, Alaska's average annual temperature is expected to rise between 8 and 13 degrees Fahrenheit compared to the 1960s and 1970s if greenhouse gas emissions continue unabated.
Dramatic temperature changes in Alaska are already causing the landscape to change faster than anywhere else in the United States, threatening infrastructure, wildlife, and native culture.
Alaska: not so permanent permafrost
Alaskan villages, like Shishmaref, are finding the land they call home literally melting beneath them. Warmer winters have allowed once reliably frozen tundra, called permafrost, to melt, causing homes and buildings to sink and foundations and roads to crack and warp.
Reducing protective sea ice and rising sea levels make coastal villages more vulnerable to tides, storms and increased erosion. According to an analysis by the Army Corps of Engineers, as global warming changes the contours of Alaska's shores, entire towns are faced with the need to relocate inland at a cost of tens of millions of dollars.
But coastal villages aren't the only things at risk in Alaska. The water and sanitation infrastructure throughout Alaska is threatened by melting permafrost. Structures such as roads, buildings, pipes, and power lines built on permafrost can shift, warp, or collapse as the soil melts and softens. Damage from permafrost thaw, increased flooding, and coastal erosion as a result of global warming could add $ 3.6 to $ 6.1 billion to public infrastructure costs in Alaska by 2030.
Even nature's infrastructure can suffer from permafrost melt. Drunken forests occur when permafrost melts, leaving trees leaning at odd angles. But leaning trees aren't the only problem for Alaska's forests. In many areas, rainfall has subsided, leading to drier conditions and more wildfires. Alaska's white spruce forests, for example, are already suffering from drought stress. Warmer temperatures have also brought in more damaging outbreaks of pests. As trees burn or decompose, they release stored carbon into the atmosphere.
Changes in the ecosystem
Arctic biodiversity is also in danger from global warming and ocean acidification. Significant changes include declines in populations of seabirds and marine mammals and declining salmon harvests upon returning to spawning grounds.
The number of sea lions has decreased between 50 and 80 percent in recent decades. The polar bear relies on summer sea ice to hunt seals. As the extent of sea ice shrinks, so does polar bear habitat. On land, scientists have documented a doubling of coastal erosion and lake changes in the past two decades, impacting critical habitat for caribou and migratory birds.
The decline of these iconic Arctic animals affects Alaska's indigenous communities, as they depend on hunting, trapping and fishing for their subsistence. Beyond the importance of diet and health, these activities also represent a unique and important part of indigenous cultures.
Reduced or displaced populations of marine mammals, seabirds, and other wildlife combine with shrinking and thinning sea ice to make traditional livelihoods more difficult and more dangerous for Alaska Natives.
Original article (in English)