Second only to the Antarctic ice sheet, the Greenland ice sheet is almost 2,400 kilometers in length and around 1,100 kilometers in width at its northern margin. Roughly, the ice sheet covers around 1.7 million square kilometers, which is equivalent to around 80% of the surface of Greenland. At the same time, the depth of the Greenland ice sheet is more than 4 kilometers and consists of compressed snow fallen during the past 100,000 years. Thus, being the second largest ice mass on the planet and having evolved over thousands of years, the Greenland ice sheet is significant on many different fronts.
Significance of maintaining the sea level
One of the major significance of the Greenland ice sheet is its value in maintaining the sea level. Because of global warming, scientists have observed that the Greenland ice sheet is thinning at a significant rate and according to their estimates, the annual loss of ice from this sheet is around 200 gigatonnes. Such a loss can raise the global sea level by about 0.6 mm per year and in a worst-case scenario, the entire Greenland ice sheet if melted could raise the global sea level by about 7 meters. Although such a scenario may not take place in the near future, even a sea-level rise of around few inches can completely wipe out some islands, cities and coastal belts.
However, climate experts warns that, unless there are concrete measures to control the carbon dioxide and other greenhouse gas emissions, the earth’s temperature could rise drastically and when the temperature rise equals to around 3 degrees Celsius (the threshold value), it could pave way for a complete meltdown of the Greenland ice sheet. At the same time, the global climate model suggest that at present rate of change, the ‘threshold’ might be reached by the year 2100 and unless the present climate change slows down and falls to the levels of the year 2000 before the year 2050, the worst-case scenario of rising sea levels may become a reality.
Significance of holding information related to past climates
Apart from its significant contribution towards maintaining the sea level, the Greenland ice sheet also harbors a wealth of information related to thousands of years of climate change in more detail than any other means of storage. However, in order to gather climate related information, scientists had to drill up to 4 km of the ice sheet. During the drilling, they were able to unearth many proxies, which explain certain parameters related to particular climates, which existed in the past. Based on these proxies, the scientists can predict the temperature, ocean volume, chemistry and gas composition of the lower atmosphere, precipitation, solar variability, sea surface productivity, dessert extent as well as the forest fires related to a certain period of time represented by a layer in the ice sheet.
When considering the other sources of information with regard to past climates, the Greenland ice sheet is the richest source. With further research, the scientists may unravel many secrets that are buried deep within the ice core that could change the way we think of how the earth has evolved over many millions of years.
The Greenland ice sheet is an enormous mass of ice, which helps maintain the global sea level and the ocean currents. It also harbors a rich source of information related to past climates, which can provide the scientists with vital clues as to the evolution of the planet earth.