Glaciers present today have taken centuries to form. They keep on melting, forming rivers and lakes; essential for human survival in many places across the world. This melted ice is replaced by fresh snow that is converted into ice over time. Things start going wrong when the water that is melting is more than the snow that is replacing it.
What are GlaciersGlaciers are formed by fallen snow that gets compressed into solid ice over a period of time. New layers of snow fall over the formed ice, compacting the layers of ice below. This is a constant process, making the glacier thicker and bigger over a period of time.
Glaciers are also known as 'rivers of ice' because they are not stationary but moving constantly like the water of a river; onlymuch slower, from a few millimeters a day to a few meters a day.
How are Glaciers Formed
Glaciers are formed by snow. This snow keeps on freezing and thawing (depending on the climate and temperature) and finally gets converted into ice. This ice gets compacted and firmer when a new layer of snow falls over it and compresses it under pressure. As more snow gets converted into ice, the weightand size of the glacier keeps increasing. An increased weight helps the layers of ice to start moving slowly (thus the nickname 'rivers of ice'). The upper layers of the glacier are usually not compressed to the levels of the lower layers and are more brittle, forming deep cracks (crevasses) as they move.
Is Ice Glaciers Melting Normal
It is normal for ice glaciers to melt. Ice glaciers eitherbreak off into smaller icebergs and melt directly into the sea, or melt on land and form rivers that will empty into the sea.
Sea water is evaporating constantly and is replaced by melting glacier water. A problem here occurs when the snow replenishing it is less than the melted water. This is exactly what is happening with most of the glaciers around the world today, gradually reducing thesize of the glacier, at the same increasing the sea water level.
Effects of Melting Ice Glaciers
Glacier ice is melting much faster today than was expected. This has got serious effects on the earth, mostly negative.
Temperatures across the globe have gone upward, helping the cause of ice glaciers melting faster than required. In certain places across the world small iceglaciers have totally vanished, exposing the earth below. Ice glaciers are able to deflect almost 80% heat of the sun, absorbing approximately 20% heat. This figure gets reversed when sunlight falls on earth, 80% is absorbed and only 20% is deflected back. This in turn helps in increasing global temperatures. This leads to an increase in the temperature of sea water. Icebergs melt faster. Added tothis is the expansion of sea water, leading to a rise in sea water levels.
Fresh Water Shortage
When seen from outer space, the earth looks self-sufficient in its need for water; in reality it is just the reverse. Almost all this water seen from space is salt water; unfit for human use. Just over 2% of this water is freshwater that is fit for human use; and over 70% of this 2% make-up the earthsglaciers. Many on earth depend on the melting water from glaciers for their fresh water supply through lakes and rivers. The melted water gets renewed as ice on the glacier through a process known as precipitation. In many parts of the world this is the 'only' source of fresh water supply throughout the year. An ever-increasing human population and a rapidly decreasing glacier mass will lead tosevere fresh water shortage in the near future (some places like those surrounding the Himalayas are already facing a crisis of fresh water shortage, especially in the dry months).
Reduced Agricultural Output
Agriculture that depends solely on rain will be mostly unaffected by the effects of ice glaciers melting. Such areas are very few worldwide and do not contribute to the major chunk of...