The Greenland Ice Sheet is an ice sheet covering Greenland, the largest island in the world. The Greenland Ice Sheet is the second largest ice sheet in the world. Due to global warming, the Greenland ice sheet is in the process of melting.

Introduction

A single ice sheet covering about 84.7% of Greenland is the largest ice body in the northern hemisphere. It is 2,530 kilometers long from north to south, the widest (near the northern edge) is 1,094 kilometers, and the average thickness is about 2,300 meters (meters). The known maximum thickness is 3,415 meters and the area is about 1,833,900 square kilometers. Covering the dish-shaped basin, the surface of the bedrock is as high as the sea. The center of the ice sheet is thicker than the surrounding edges, and there are two rising ice domes. The northern one is in central and eastern Greenland, with an altitude of 3,000 meters. It is the thickest place with the lowest temperature, with an annual average of -31°C (-24°F).

An altitude of 2,500 meters to the south. The ice layer moves from the peak to the surroundings, and its edge to the fjords along the coast of Greenland forms many outflow glaciers, which flow into the ocean and become countless icebergs. The ice sheet accounts for 12% of the world’s total glacier water. Once it melts, the sea level will rise by 7 meters. In the 1970s and early 1980s, scientists from the United States, Denmark, and Switzerland collaborated to study the dynamics of the ice sheet and its impact on the climate.

The existing continental ice sheets on the earth include the Antarctic Ice Sheet and the Greenland Ice Sheet. These two ice sheets account for about 97% of the global glacier area and 99% of the total ice volume. The Antarctic ice sheet accounts for about 85.7% of the world’s total glaciers, and the Greenland ice sheet accounts for about 10.9%.

It was formed in the Quaternary Period. At about 18,000 years ago, the area of ​​the ice sheet was 7 times larger than that of today, and it was connected to the North American ice sheet at that time. Most of Greenland is located in the Arctic Circle, with an area of ​​2,166,313.56 square kilometers, making it the largest island in the world.

The Greenland ice sheet covers an area of ​​about 1.8339 million square kilometers, with an average thickness of about 2,300 meters, and a maximum thickness of 3,400 meters, accounting for 9.7% to 11% of the world’s ice volume. It is composed of two dome-shaped ice sheets connecting the north and the south. The edge of the ice sheet covers the sea. There are many glaciers whose tongues extend to the sea, forming many icebergs in several fjords.

Some of the glaciers in West Greenland, such as the Jakobshavn Isby Glacier, flow at a speed of 7,000 meters per year, making it the fastest-moving glacier in the world. The ice surface on the west side of the middle part of the ice sheet is thickening at a rate of 0.1 meters per year, while the east side is slightly thinning. The ice surface in the ablation zone on the west coast of the ice cap is thinning about 0.2 meters per year.

The Greenland ice sheet shows stronger polar oceanic glacier properties. The southwestern coast of the ice sheet is affected by the West Greenland Warm Current. The climate is relatively warm. The average annual temperature is as high as 1℃. The average temperature in January and July is -7.8℃ and 9.7℃ respectively. The annual precipitation reaches 1,000 mm, and the accumulation of snow and ice. And the amount of ablation is very large.

The conditions inside the ice sheet are significantly different. The annual average temperature is about -31°C. The average temperatures in January and July are -47.2°C and -12.2°C, respectively. The annual precipitation is only 200 mm. The temperature is low, the precipitation is low, and snow and ice accumulate. The amount and the amount of melting are small, and the ice formation process is slow. For example, the ice formation process of the Century Camp (77°11′N, 61°10′W) takes 125 years.

Greenland ice sheet-melting

The Greenland Ice Sheet is second only to Antarctica in size, but it is more fragile. It is farther from the cold polar regions than the Antarctica ice sheet. The southernmost ice sheet is located south of 60 degrees north latitude, almost at the same latitude as the Shetland Islands in northeastern Scotland.

Over the centuries, the decline of the Greenland ice sheet has been balanced: in summer, glaciers break ice and meltwater into the ocean; in winter, frozen snow replenishes the ice sheet.

Since the 1990s, the Greenland ice sheet covering most of Greenland has been melting faster and faster. According to satellite research in 2006, the ice sheet pushes up to 240 cubic kilometers of water into the sea every year. Greenland is a secondary reason for raising concerns about how the three-dimensional rise of the sea will affect coastlines all over the world.

In 2010, a team of scientists warned in a report to the U.S. Congress that if the temperature rises by 2-7°C, the entire ice layer of Greenland will disappear from the world map. It has a serious impact on other parts of the world.

According to Richard Alley, a professor of earth sciences at Pennsylvania State University, in August 2010, a huge ice floe collapsed from Greenland’s Peterman Glacier. The area of ​​the fractured ice floe is equivalent to four Manhattans. It may be history. The largest floating Iceland that has collapsed from a glacier on record. He thinks this is Greenland’s warning to mankind.

The latest (September 2010) study by American scientists found that the permanent ice sheet on Greenland, Denmark is melting at the fastest rate in nearly a century, especially in summer. Climatologist Menild of Los Alamos National Laboratory in the United States said that the volume of the ice sheet that melted on Greenland this summer was as high as 540 cubic kilometers, which was 25% to 50% higher than normal years. In the last 10 to 12 years, the summer temperature in Greenland has increased year by year.

Calculations show that the volume of ice sheet melting in summer is larger than ever before. The rapidly melting ice may cause sea levels to rise, and it may also pose dangers to lower-lying countries and regions. Menild pointed out that in the summer of 1972, only 17% of Greenland’s ice sheet melted, and this summer the percentage was as high as 52%.

Climatologists at the Polar Research Center of Ohio State University in the United States have also concluded that the melting rate of the Greenland ice sheet this year is the fastest since 1873.