Category Weather, Climate, Ecology

WHAT ARE THE LARGEST BODIES OF ICE IN THE WORLD?

In today’s world, the ice sheets of Antarctica and Greenland. An ice sheet is a continuous mass of ice covering more than 50,000 km2. The ice sheet in Antarctica covers 14 million km2. It is 1.6 to 6.4 km thick and holds 30 million km2 of ice. The Greenland ice sheet covers about 1.7 million km2.

The Antarctic ice sheet is the largest block of ice on Earth. It covers more than 14 million square kilometers (5.4 million square miles) and contains about 30 million cubic kilometers (7.2 million cubic miles) of water.

The Antarctic ice sheet is about 2 kilometers (1.2 miles) thick. If it melted, sea level would rise by about 60 meters (200 feet).

The Greenland ice sheet is much smaller than the Antarctic Ice sheet, only about 1.7 million square kilometers (656,000 square miles). It is still the second-largest body of ice on the planet.

The Greenland ice sheet interacts much more dynamically with the ocean than the Antarctic ice sheet. The annual snow accumulation rate is more than double that of Antarctica. Glacial melt happens across about half of the Greenland ice sheet, whereas it is much more isolated on the far western part of Antarctica. Greenland’s ice shelves break up much faster than those surrounding Antarctica.

Both the Antarctic and Greenland ice sheets have caused the land under them to sink. Eastern Antarctica is about 2.5 kilometers (1.6 miles) below sea level because of the colossal weight of the ice sheet above it.

Credit: National Geographic

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IS ANTARCTICA A DESERT?

A desert is defined by the amount of precipitation (rain, snow, mist and fog) in an area. A region that receives very little precipitation is classified as a desert. There are many types of deserts, including subtropical, coastal and polar deserts. What they all have in common is a barren, windswept landscape, which makes it difficult for plants and animals alike to gain a foothold on land. This all certainly applies to Antarctica.

The average yearly rainfall at the South Pole over the past 30 years was a tiny 10 mm (0.4 in). Most of the continent is covered by ice fields carved by the wind, and craggy mountains covered in glaciers. While Antarctica is home to wonderful forests of low-lying mosses and lichens, there are only two flowering plants that can survive the harsh conditions. And most of the animals we encounter – penguins, seals, whales and seabirds – rely on seafood for sustenance.

Credit: aurora expeditions

 

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HOW OLD IS GLACIER ICE?

  • The age of the oldest glacier ice in Antarctica may approach 1,000,000 years old
  • The age of the oldest glacier ice in Greenland is more than 100,000 years old
  • The age of the oldest Alaskan glacier ice ever recovered (from a basin between Mt. Bona and Mt. Churchill) is about 30,000 years old.

Glacier flow moves newly formed ice through the entire length of a typical Alaskan valley glacier in 100 years or less. Based on flow rates, it takes less than 400 years for ice to transit the entire 140 + mile length of Bering Glacier, Alaska’s largest and longest glacier.

Picture credit: Google

HOW MUCH OF THE WORLD IS COVERED BY ICE?

Almost 10 per cent of Earth’s total landmass is covered by ice. This includes glaciers, Ice caps and ice sheets. Glaciers cover 15 million km2. During the last ice age, 32 per cent of the total land area was covered by ice.

Most of the Earth’s ice that we see is to be found in large masses of “nearly” pure ice: ice-sheets and glaciers of various types, ice shelves and sea ice packs. It is quite easy to calculate the surface of the areas covered with ice: it has been calculated that this amounts to approximately 15 million km2, equal to one tenth of the surface of the Earth’s emersed land. It is more difficult, on the contrary, to calculate the volume of ice because the thickness of the entire covered area must be known: using special techniques it is possible to measure the ice thickness in various points of a glacier and therefore to estimate the volume. For example the average thickness of the Antarctic sheet is 2,100 m, with peaks of 4,800 m in Land of Wilkes, in the Eastern sector: with a surface of little less than 13,600,000 km2, the total volume of the Antarctic ice is 30 million km3.

Credit: Energy & environment

Picture credit: Google

 

DOES ANTARCTICA HOLD MOST OF THE WORLD’S FRESH WATER?

The Antarctic ice cap contains about 91% of all the ice in the world and about 86% of all freshwater that occurs in the form of ice. But despite all this freshwater, Antarctica is considered one of the most arid places on Earth.

Antarctica is the highest, coldest, driest, and windiest of the world’s continents. It is also “tallest” in terms of average height above sea level. Nearly 99% of this land mass is covered with an ice cap with an average altitude of around 2 200 metres above sea level. The area of this vast continent – some 14 million square kilometres – doubles in the winter, when sea ice can stretch as much as 1000 km outwards from the coastline.

Most of the continent of Antarctica lies south of 70°S, although the Antarctic Peninsula stretches northward as far as 60°S. The continent is surrounded by the Southern Ocean, a circumpolar sea that isolates Antarctica from the other continents.

Most of Antarctica is covered with ice, but in many places mountain peaks (nunataks) stick up out of the ice. The Vinson Massif in West Antarctica, with an elevation of 5 140 m, is the highest peak in Antarctica. In addition to the nunataks, there are large ice-free regions called oases where the ice has retreated and where melting outstrips accumulation of new snow. Other areas, known as dry valleys, are free of ice because essentially no precipitation falls there.

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WHAT IS DESERTIFICATION?

The process by which natural or human causes reduce the biological productivity of drylands (arid, semi-arid and dry sub-humid areas) is known as desertification, also referred to as desertization. Climate change, deforestation, overgrazing, unsustainable irrigation practices, political instability, poverty, or a combination of these factors generally result in declines in productivity of drylands. Africa has been the continent that is most affected by desertification.

Desertification, in short, is when land that was of another type of biome turns into a desert biome because of changes of all sorts. A huge issue that many countries have is the fact that there are large pockets of land that are going through a process that is known as desertification.

Desertification affects topsoil, groundwater reserves, surface runoff, human, animal, and plant populations. Water scarcity in drylands limits the production of wood, crops, forage, and other services that ecosystems provide to our community.

According to UNESCO, one-third of world’s land surface is threatened by desertification, and across the world, it affects the livelihood of millions of people who depend on the benefits of ecosystems that drylands provide.

Various Causes of Desertification

1. Overgrazing

Animal grazing is a huge problem for many areas that are starting to become desert biomes. If there are too many animals that are overgrazing in certain spots, it makes it difficult for the plants to grow back, which hurts the biome and makes it lose its former green glory.

2. Deforestation

When people are looking to move into an area, or they need trees in order to make houses and do other tasks, then they are contributing to the problems related to desertification. Without the plants (especially the trees) around, the rest of the biome cannot thrive.

3. Farming Practices

Some farmers do not know how to use the land effectively. They may essentially strip the land of everything that it has before moving on to another plot of land. By stripping the soil of its nutrients, desertification becomes more of a reality for the area that is being used for farming.

4. Excessive Use of Fertilizers and Pesticides

The use of excessive amounts of fertilizers and pesticides to maximize their crop yields in the short term often leads to significant damages for the soil.

In the long run, this may turn from arable into arid land over time, and it will no longer be suitable for farming purposes after a few years of excessive farming since the soil has been damaged too much over time.

5. Overdrafting of groundwater

Groundwater is the freshwater found underground and also one of the largest water sources. Over drafting is the process in which groundwater is extracted in excess of the equilibrium yield of the aquifer that is pumping or the excessive pulling up of groundwater from underground aquifers. Its depletion causes desertification.

6. Urbanization and Other Types of Land Development

As mentioned above, development can cause people to go through and kill plant life. It can also cause issues with the soil due to chemicals and other things that may harm the ground. As areas become more urbanized, there are fewer places for plants to grow, thus causing desertification.

7. Climate Change

Climate change plays a huge role in desertification. As the days get warmer and periods of drought become more frequent, desertification becomes more and more eminent.

Unless climate change is slowed down, huge areas of land will become desert; some of those areas may even become uninhabitable as time goes on.

8. Stripping the Land of Resources

If an area of land has natural resources like natural gas, oil, or minerals, people will come and mine it or take it out. This usually strips the soil of nutrients, which in turn kills the plant life, and eventually leads to the process of becoming a desert biome as time goes on.

There are some cases where the land gets damaged because of natural disasters, including drought. In those cases, there isn’t a lot that people can do except work to try and help rehabilitate the land after it has already been damaged by nature.

8. Soil Pollution

Soil pollution is a significant cause of desertification. Most plants are quite sensitive to their natural living conditions. When soil becomes polluted due to various human activities, the respective area of land may suffer from desertification in the long run. Higher the level of pollution more will be the degradation of soil over time.

9. Overpopulation and excessive consumption

Since our world population is continuously growing, the demand for food and material goods is also increasing at an alarming rate. Our overall level of consumption is also increasing at a steady rate.

Thus to fulfill our demand, we have to optimize our farming processes to harvest even higher crop yields. However, this excessive optimization of farming will hurt the soil and will eventually turn into the desertification of land in the long run.

10. Mining

Mining is another big reason for desertification. Large amounts of resources have to be extracted by industries to meet our demand for material goods. For mining, large areas of land have to be used, which causes deforestation as well as pollution of the nearby areas.

By the time most of the natural resources have been extracted, and mining practices are no more profitable, the soil gets damaged significantly, and the land becomes arid, which may not be recoverable, and desertification occurs.

Picture Credit : Google