Glaciers and Ice Sheets
Leading figures from the World Glacier Monitoring Service have warned that the planet’s glaciers are melting so fast that many will disappear by the end of the century.
Mountainous glaciers are retreating in many parts of the World and one particular area, scientists are concerned about is Alaska – the Columbia Glacier there has retreated 15km over the past 25 years. The glaciers retreat when there is less snow in the winter than what is melted away in the summer.
Many of the mountains in the area are now severely depleted of snow. It is believed the situation is so extreme in Alaska that of the 2,000 glaciers observed, 99%of them are retreating.
In Europe, the situation is worrying too. Europe’s glaciers are thought to have lost around a quarter of their mass in the last 8 years.
Although melting glaciers aren't the main cause of sea level
rises (that's thought to be the result of surface air temperature rises), the effects of glaciers certainly contributes and is a concern to scientists.
An ice shelf sits over water but is attached to the ice sheet. If the ice shelf breaks off sea levels won’t be affected. This is different from an ice sheet which sits on land. If it
melts, sea levels will rise.
In April 2009 an ice bridge linking a shelf of ice the size of Jamaica to two islands in Antarctica snapped. Many scientists believe the collapse could mean the Wilkins Ice Shelf is on the brink of breaking away and that this provides further evidence of rapid change in the region. Sited on the western side of the Antarctic Peninsula, the Wilkins shelf has been retreating since the 1990s.
Temperatures in parts of Antarctica have risen higher than the global average (2.5C over the past 50 years), the reason for which is unclear. However, man-made climate change is seen by many to be playing a crucial role in this process.
Sea level rises