click here to enlarge
Armstrong, climate change: snow and ice cover
Submitted by share-everest on Wed, 04/30/2008 - 15:51.
Fluctuations of the Earth’s snow and ice cover provide one of the most visually obvious and dramatic examples of climate change. Direct and indirect measurements of air temperature over past centuries indicate periods of both cooling and warming, although in the most recent decades the Earth, in almost all locations, has experienced a dramatic warming trend.
Some ice core records indicate that the last 50 years have been the warmest within the last 1000 years. It is not surprising that snow and ice cover have been responding to this trend of increased warming.
Although glaciers exist at both high latitude and high altitude, it is the latter, the mountain glaciers, which are most important with respect to water resources. Glaciers in virtually all regions of the world have been shrinking in area since the end of the Little Ice Age, or since about 1850. However, in apparent response to the more recent significant increases in air temperatures, the retreat of glaciers has greatly accelerated.
This presentation provides examples of glacier retreat trends as well as decreasing trends in seasonal snow cover. There is also evidence that climate warming in the mountains has exceeded, and began at an earlier date, than that measured at lower elevations.
The accelerating loss of mountain snow and ice cover impacts society in many ways including winter recreation, tourism, water resources for agriculture and human consumption, hydropower, and management of hazards. Accurate predictions of the response of mountain snow and ice reserves to future climate change patterns will be essential to successful resource planning in many regions of the world.