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The polar regions are the regions surrounding the North Pole and the South Pole.
The amount of heating the Earth's surface receives depends on a number of factors. These
include solar elevation (solar angle), cloud cover, length of day, and to a lesser extent,
the length of path the Sun's rays must take through the atmosphere. As the rays pass through
the atmosphere, some of the radiation is absorbed, reflected or scattered. The Equator is warmer
than the UK because the angle at which the Sun's rays strike the surface is much higher,
more direct illumination causes a more intense amount of heating. At the Poles it is colder
because the angle that the Sun's ray strikes the Earth is much lower and the intensity
of heating is less. Ice dominates the polar landscape but actually
north and south are very different because the North polar region is mostly water, the
Arctic Ocean, while the South polar region is mostly land -- the continent of Antarctica.
There are two main types of polar environment -- ice cap environments, where no month in
the year has an average temperature above zero degrees centigrade, and tundra environments,
where at least one month has an average temperature above zero degrees.
In the polar winters , when the pole is facing away from the sun, the sun 's rays don't reach
that polar region at all: it is dark for 179 days of the year at the North Pole and the
South Poles themselves but at the very edge of the polar regions it is completely dark
for only about one day a year. These conditions mean considerable differences
can be over 10 degrees centigrade but winter temperatures can be below minus 50 degrees
centigrade. This difference between seasons is called seasonality.
Because it is land rather than the sea, Antarctica is much colder all year and summer temperatures
are usually only about 2 degrees centigrade. Winters are very cold indeed. The coldest
centigrade and only around 160 milimetres of precipitation a year -- it's technically
As well as being too cold for plants, it is often very dry as well.
3 There are two main types of polar environment
-- ice cap environments, where no month in the year has an average temperature above
zero degrees centigrade, and tundra environments, where at least one month has an average temperature
above zero degrees. In the polar winters , when the pole is facing
days of the year at the North Pole and the South Poles themselves but at the very edge
of the polar regions it is completely dark for only about one day a year.
These conditions mean considerable differences between winter and summer in the polar regions.
In the Artic polar region, summer temperatures can be over 10 degrees centigrade but winter
temperatures can be below minus 50 degrees centigrade. This difference between seasons
is called seasonality. Because it is land rather than the sea, Antarctica
is much colder all year and summer temperatures are usually only about 2 degrees centigrade.
Winters are very cold indeed. The coldest temperature ever recorded was in an Antarctic
winter: minus 89 degrees centigrade. Away from the coasts, Antarctica has and average
annual temperature of minus 57 degrees
centigrade and only around 160 milimetres of precipitation a year -- it's technically
a desert. In ice cap environments no plants can grow.
As well as being too cold for plants, it is often very dry as well.
4 Each winter the Artic Ocean freezes over but
much of it melts again in the short summer. But when ice cap environments are on land,
some snow accumulates year after year and turns to ice. Eventually, enough ice accumulates
for it to start to flow down hill -- a glacier. Glaciers are very powerful at eroding the
Each winter the Artic Ocean freezes over but much of it melts again in the short summer.
turns to ice. Eventually, enough ice accumulates for it to start to flow down hill -- a glacier.
Glaciers are very powerful at eroding the land under the ice. Some parts of the UK had
ice cap environments during Ice Ages, when the climate was colder than now. The landscapes
left behind by the glaciers are very distinctive, with deep, U-shaped valleys gouged out by
the glaciers.
Tundra environments, where at least one month of the year has average temperature above
freezing, do have some vegetation, but it is still too cold and dry for trees. The main
things that do grow are moss and lichen. While there may be a thin layer of soil, under that
the ground is frozen solid -- called permafrost. In summer the top level of the soil unfreezes
but the permafrost doesn't. The meltwater as nowhere to go, so the landscape is very
marshy and boggy.
Animals that live in the tundra are adapted to the very cold winters and short summers,
and to the very low biodiversity.
But because they are so well adapted to these conditions, they are vulnerable to any changes.
This makes the polar region a fragile environment.