National Geographic Society
National GeographicNat Geo Wild


The vast majority of people living on Earth will never see a glacier during their lifetime, but the truth is that they have an impact on the lives of everyone living on the planet. Glaciers currently cover 10% of the Earth’s landmass and hold as much as 75% of the world’s total freshwater. If the world’s glaciers retreat and melt, the impact on the environment and geography will be dramatic, having a significant impact on how we live our lives in the future too.
Find out below why glaciers are so important and how they are going to change the way we live our lives in the future.

What is a Glacier?
Glaciers are essentially rivers of ice that grow and contract dependent on different conditions such as snowfall and temperatures. Glaciers are formed after snow becomes compact into ice and then under its own weight begins to move down along a valley. As more snow builds up the snow becomes more compact and quickly forms a strong mass of moving ice.
Glaciers are dependent on cold weather to survive, so they are usually, but not exclusively, found close to the two poles in Antarctica and the Arctic. They are also found away from the Poles in mountainous areas such as the Alps and the Rocky Mountains where the elevation is high enough for the temperatures to be consistently low enough for glaciations.

Why are the glaciers melting?
There is only one reason why glaciers are melting – the world’s climate is getting hotter. But what is causing the Earth to become warmer and our climate to change is far from certain.
While few scientists argue that man-made factors such as air pollution and burning fossil fuels have not played their part in global warming, the extent to which humans can be held responsible is hotly debated. For example, from the sixteenth to the mid nineteenth century the Earth’s temperature was significantly lower than it had been in the medieval period or that it is today.
Referred to as the ‘Little Ice Age,’ average temperatures around the world were 1-1.5 C cooler than they are today. Lower temperatures around the world led to significant glacier growth across the globe. Experts believe the drop in temperature during the ‘Little Ice Age’ may have been caused by the effects of large eruptions from volcanoes.
But while changes to the Earth’s temperature may have some natural basis, it looks like human activity is also increasingly having an effect on global temperatures worldwide and the shrinking of the Earth’s 160,000 glaciers.
A combination of burning large amounts of fossil fuels, such as coal, oil and gas, as well as the massive deforestation – the cutting down of vast tracts of trees by loggers - across the globe means that there is more CO2 in the environment and more heat in the atmosphere, pushing temperatures up.

How much are the world’s glaciers melting by?
There is no denying that glaciers are melting at an increasingly fast rate. Figures released by the World Glacier Monitoring Service at the University of Zurich in Switzerland for 2007 claimed an average loss of ice thickness of 0.67 metre water equivalent (mwe), with some glaciers in the Alps losing as much as 2.5 mwe. Metre Water Equivalent is the method used by glaciologists as a standardized unit for measuring the density change of ice: one metre of ice thickness is equal to about 0.9 mwe.
In Greenland, researchers reported that the amount of ice melting was nearly three times faster in the summer of 2008 than it had been in 2007. Researchers from Ohio State University estimated that the amount of ice lost from Greenland’s glaciers in 2008 would cover an area twice the size of Manhattan.
A 2002 study claimed that Alaska’s glaciers are losing as much as 1.8 metres of ice a year, more than twice the levels recorded in the 1950s. Some glaciologists believe that glaciers are losing 22 cubic miles (92 cubic kilometres) of ice per year – equivalent to the amount of water the US uses every four months. Figures suggest that if all the ice held in the world’s glaciers melted sea-levels would rise by as much as 70 metres worldwide – flooding vast tracts of land and transforming the planet’s geography in the process.
But while the world’s glaciers are melting and sea levels undoubtedly rising, there is some good news. Recent studies have shown that sea levels may not rise by as much as scientists first predicted. While many projections see global sea levels as being 20 feet higher by 2100, a study in 2008 by the University of Colorado at Boulder claims that a sea level rise of more than 6 feet is unlikely by 2100.
However, even a sea level rise of this amount would cause devastating effects across the planet, with significant population numbers – 70% of the world’s population - living on low-lying coastal plains.



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