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Polar Climates
By Meghan

Polar climates are areas of the planet that are covered with glaciers or a permanent or semi-permanent layer of ice and where there is an absence of trees.  Polar climates do not include parts of the world where these cold conditions exist due to the high elevation of particular mountains ranges.  Instead, these areas are referred to as having an Alpine climate. 
There are two types of polar climates.  The less severe of the two is the “tundra climate” and the colder one is known by various names including the “ice cap climate” and the “perpetual frost climate.” These polar climates are predominantly found near the north and south pole regions of the planet.  In the northern hemisphere, Greenland has polar climates for all but a few coastal areas of the island.  The northern most parts of Europe, from the northeastern coast of Scandinavia and eastwards to the Bering Strait, as well as large areas of northern Siberia and Northern Iceland have the less severe, tundra climates.  There are large areas in northern Canada and northern Alaska with tundra climates changing to the more severe ice cap climates in the very northern most parts of Canada.  Polar climates have also been observed on other planets, such as Mars, which has visible ice caps at both poles. 

The tundra climate is defined as having at least one month of above freezing average temperatures.  It is characterized as having long, harsh winters, low average temperatures, little rain or snowfall and short summers.  The most distinctive characteristic of the tundra soil is its permafrost, a permanently frozen layer of ground up to 2000 feet thick. Shallow rooted tundra plants and microorganisms grow in the permafrost. In the Arctic tundra animals such as caribou (reindeer), musk ox, arctic hare, arctic fox, snowy owl, lemmings, and polar bears (only the extreme north) live.  In the Antarctic region, there are far fewer animal species due to the isolation of this glacier covered continent and to the lack of human habitation bringing non-native species to the region. However, Antarctica is home to many different birds including the penguins and several different species of seals.  The water surrounding Antarctica draws many marine animals to the region, especially in the austral summer months.  Animals living in both the far northern hemisphere and southern hemisphere have adapted to handle the cold winters and to breed and raise their young in the shorter summer months.

Summers are usually brief periods of milder climates when the sun shines almost 24 hours a day. This is when the land can be referred to as "the land of the midnight sun". But even the sun can't warm the tundra much. Average yearly temperatures range from -70 degrees F to 20 degrees F.  During the long winter months, the sun barely rises above the horizon and it is dark for most of the day. Bitter cold winds and snow blow across the barren landscape, exposing high plateaus to barren ground.  The climate is also very dry with precipitation of 6-10 inches of rain a year, which includes melted snow.

The second polar climate, known as the ice cap climate or the perpetual frost climate, can be found near the north and south poles of the Arctic and Antarctic.  In the Northern hemisphere, the ice cap climate is found over the interior of Greenland and the permanently frozen portions of the Arctic Ocean and associated islands.  In the Southern Hemisphere, the ice cap climate can be found in Antarctica, where this glacier covered continent experiences the coldest temperatures on earth, especially during the long polar nights. These ice cap climate zones have no average monthly temperatures above freezing. Humidity is so low in these areas that precipitation amounts are comparable to some of the driest desert regions.  As a result, they are sometimes called “polar deserts.”

At the surface of the permafrost, the "active" layer thaws during the summertime and subsides or moves down slope. During the winter months, the surface heaves as it refreezes. The alternating freeze-thaw cycles make it difficult to build structures.  Due to the shifting “active” layer at the surface of both the north and south poles, there are markers indicating the geographic poles that have to be moved each year, usually on New Year’s Day to account for the shifting ice. 

For instance, at the Amundsen-Scott South Pole Station, there is a metallic sphere on a plinth embedded in the ice, surrounded by the flags of the countries who signed the Antarctic Treaty. This ceremonial marking is located a few meters from the Geographic South Pole, which is marked only by a small sign, and a stake. Because the ice cap is moving at approximately 10 meters per year, the stake has to be repositioned every year on New Year’s Day.  This movement of the ice together with the snow accumulation around the structures, make it difficult to build and maintain access to buildings in these areas.

The two types of polar climates, near the north and south poles of the planet, have some of the coldest and harshest weather found on Earth.  This is because they have the least amount of direct sunlight and thus experience extremely cold temperatures.  These very low temperatures result in very little moisture in the air and not a lot of snowfall. The tundra climate is the less severe climate and can be found along the warmer, coastal regions where some plant life and animals are able to make their homes, especially during the summer months. The more severe ice cap climates are the harshest areas located near the poles where the climate is bitterly cold year round. These areas experience frequent storms and blizzards with hurricane-force winds which make it difficult for animal and plant life. While more species of animals and plants can be found in the polar climates in the north, Antarctica accounts for the least number of animals and flora in the world.