We keep on getting news that glaciers are melting because of the global warming and this will contribute to the sea level rise significantly. This sort of information naturally makes us curious about glaciers. We want to know how many glaciers are there in the world and where are they located? Are they any different from ice sheets and from where to get the most authentic information about them. The post tries to provide information about these queries.
Most of the ice in the world is present in the form of ice sheets, ice caps and glaciers. The combined area of these ice shapes is known as total glaciated area.
Most glacial ice sheets are present in Antarctica and Greenland. More than 90% ice in the earth is present as ice sheets of Antarctica. Ice sheets are dome-shaped and are greater than 50,000 square kilometres.
However, glaciers are not confined in any particular area and are present all across the planet, in all the continents. A glacier is a mass of ice that originates on land, usually having an area larger than one tenth of a square kilometre.
The information in this post focuses on glaciers and excludes ice sheets and ice caps. Glaciers cover 0.5% of the Earth’s land surface.
How many glaciers are there in the world?
The most authentic document that tells us about the glacier distribution across the earth is Randolph Glacier Inventory. It is the first collection of digital outlines of glaciers situated across the globe. These digital outlines of the glaciers have been created with the help of satellite imagery dating from 1999-2010.
The Randolph Glacier Inventory was developed to help Intergovernmental Panel on Climate Change (IPCC) scientists improve estimates of sea level rise. This inventory excludes ice sheets and account only for 1.4% of the World’s Total Glaciated area.
As per the Randolph Glacier Inventory there are total 198,000 glaciers in the world. This is based on the calculations done using a minimum area threshold of 0.1 km2. This means that anything smaller than this was not taken into account to avoid difficulties to distinguish between glaciers and snowpacks. Together, these glaciers cover 726,000 km2.
In addition, there are many small glacierets. Glacierets are very small glaciers or ice masses. If these are included in the list of glaciers their total number goes as high as 400,000.
Where are the glaciers located?
It is the arctic region where maximum glaciers are located. Out of the total glacier covered area of the earth, approximately 44% is present in the arctic region.
The Antarctic and Subantarctic region that contain more than 90% of the total ice of the world. However, most of the ice in this part is present as ice sheets. Out of total area in the earth covered with glaciers, 18% is present in this region.
Glaciers are present all over the world but at different elevations. The majority of the World’s glaciers are situated in the mid elevation ranges of ~2000 m above sea level. However, in the Antarctic region the glaciers are present at the sea level while in the Arctic Canada North glaciers are present in the higher elevations plateaus.
Most of the glaciers are found above snow line where the conditions are optimum for their existence. For a glacier to exist the region should receive high snowfall in winters and during the summer season the temperature of the region should remain low. Under such conditions, the snow that gets accumulated during the winters is much more than the amount of snow that gets melted during summers. This is why most glaciers are found either in mountainous areas or in the polar-regions.
For a glacier to survive one of the most important factors is the amount of snowfall it receives. There are some cold areas that do not receive enough snowfall such as Siberia and therefore, despite it being a cold region the Siberia has almost no glaciation.