A new report shows that glaciers near Alaska are shrinking rapidly, and climate change is causing this substantial melt. The loss of the tens of thousands of glaciers in Alaska and neighbouring British Columbia, Canada alone is deeply worrying, according to scientists. Not only is this glacial melt accelerating, but it may spell a host of problems for humans, including the rise in sea-levels, dangers to marine life, water supply and agriculture.
The recent findings are found in the U.S. National Climate Assessment (NCA), a sort of state-of-the-Union report on climate change impact released last week by the White House. This comprehensive report shows how global warming is affecting each of the major regions of the United States, the specific regional impacts, and how the varying levels of government can attempt to deal with these problems.
In the report, the NCA details ten indicators of a warming world, noting decreases in snow cover, sea ice, and glaciers and ice sheets, while air temperature, sea surface temperature, water vapour and sea level have all increased. Specifically, the average temperature in the US has increased between 1.3 and 1.9 degrees Fahrenheit, with most of that change occurring since 1970. Alaska has seen the greatest impact of this change but with temperatures projected to rise anywhere from 2 to 10 degrees Fahrenheit, depending on future fossil fuel emissions, all of North America could experience dramatic negative consequences.
Specifically, the pacific glacial melt is occurring at 20 to 30 percent of what is happening in Greenland glaciers, and will cause to 22 billion cubic meters to seep into the sea, equivalent to the total amount of water found in 8.8 million Olympic-sized swimming pools. This is a significant portion of the global glacial melt, and the climate change-caused rapid shrinking of these Alaskan and Canadian glaciers is a major part of the rise of sea-levels around the world. Over the last century, sea-levels have risen between four and eight inches, though the rate of increase in the last two decades has been double that of the previous 80 years. Recent research has also suggested that by the end of this century, there will be an increase in ocean levels of between 2.5 to 6.5 feet, with the most extreme estimates being a complete loss of the ice sheet Greenland and a 23 foot rise in sea levels.
Even with lower levels of increases, the US, along with hundreds of millions of people world-wide, would be subject to regular flooding concerns. In addition, there will be greater glacial loss, leading to problems with water supply and thus irrigation for agriculture, greater drought in summers, leading to decreases in the capture of hydroelectricity, and increased acidification of the oceans, which would reduce marine life and fish stocks, creating problems for fisheries and the coastal communities that rely on that industry.
The degree to which these consequences will affect the environment and human populations will depend on changes to policy and human behaviour, as the global warming that is causing these Alaskan glaciers to shrink rapidly is expected to continue. Policy strategies will have to change to deal with the specific regional consequences of climate change, though experts agree that the most important change will have to be a decrease in fossil fuel consumption to prevent the most dramatic worsening.
By Bryan A. Jones
Sources:
National Climate Assessment
CBC
National Geographic
