PRESENTATION OUTLINE
Glaciers are large sheets of snow and ice that are found on land all year long. They're found in the western United States, Alaska, the mountains of Europe and Asia, and many other parts of the world. Warmer temperatures cause glaciers to melt faster than they can accumulate new snow.
While there are isolated cases of growing glaciers, the overwhelming trend in glaciers worldwide is retreat. In fact, the global melt rate has been accelerating since the mid-1970s.
After 1975, glacier shrinkage continues to accelerate until present. The mass loss from 1996 to 2005 is more than double the mass loss rate in the previous decade of 1986 to 1995 and over four times the mass loss rate over 1976 to 1985. When you narrowly focus on a few cherry picked glaciers, you can be misled into an incorrect view of global glaciertrends. When you take in the broader picture, you see that globally, glaciers are shrinking at an accelerating rate.
Conclusion
Glaciers respond directly and quickly to atmospheric conditions. As temperatures warm, summer melting increases. However, accumulation of ice in the winter also increases due to more snowfall. Air temperature tends to play the dominant role - there's a strong statistical correlation between air temperature and glacier fluctuations over large distances. Generally, when air temperatures warm, glaciers recede.
