Despite all the regional variation in EF and ET climates, coldness/low annual temperatures remain a main feature that is common to all the regions of these climate types.
Both ET and EF climate types also share the feature of low precipitation, yet again this differs from region to region. Particularly in EF regions, such as Antarctica, the snowy appearance is deceptive as they are very dry regions, some of the driest on Earth in fact. At the South Pole, average annual precipitation can be as low as 50mm, and is only due to the freezing conditions that the precipitation is stored which gives the appearance of an area that receives plenty of precipitation. ET climate types however generally receive a little more precipitation to the ice cap areas, but again this varies from maritime (particularly Western coasts) to inland regions. In the maritime regions of the ET climate types, maritime influences are clearly shown from the precipitation data. Annual precipitation of Nuuk, on the South- west coast of Greenland can be more than 4 times higher than the annual precipitation figures of continental ET locations such as Ruskoye Ust’ye in Siberia. Data from Nuuk shows that annual precipitation is 598mm, which is a generally high recording for ET climate types. In continental locations of ET climate areas, the low precipitation feature is more prevalent. Data from Ruskoye Ust’ye indicates at the highest monthly precipitation comes in the months of July and August but can still be as low as 30mm. From January – April in Ruskoye Ust’ye cumulative precipitation is as low as 18mm.
Again, although with clear regional differences in EF and ET climate types, low precipitation totals are a main feature with perhaps the exception of Western coastal areas where maritime influences are received.
The third main feature of ET and EF climate types is wind chill. Strong winds that lead to wind chill are common in these polar latitudes. Wind speeds tend to be stronger in the Southern hemisphere due to fewer land masses to interrupt the movement. The high wind speeds in polar regions make the temperature feel much lower than the thermometer readings and this is wind chill.
Due to high wind speeds, wind chill (or wind chill factor) is a main feature of ET and EF climate types.
b) Describe and explain the hazards of intense cold, wind chill and low precipitation totals associated with such cold climates.
Polar Climates are hazardous due to the intense cold and high winds that they expose the body to. As wind chill makes air temperature feel even lower than it is, they body has to work much harder to stay warm. For example, if the air temperature reading in a polar climate was -12°C then a wind of 40kph would make the temperature feel like -34°C, that’s 22°C lower than the actual temperature. The reason wind chill has this effect is because wind is able to carry warm air away from exposed parts of the body and this can cause serious reductions in body temperature. The faster the wind, the greater the effects of wind chill. And example of this is an 0°C air temperature will feel like -12°C in 25kph winds but will feel like -14°C in 30kph winds. This effect is hazardous because the faster heat escapes from the body there is an increased risk of hypothermia and frostbite. Hypothermia causes the body to work to stay warm and shivering occurs in the early stages, but if the body is continually exposed to the intensely cold conditions people can become disorientated or unconscious which if left untreated can lead to death. Another hazard of being exposed to intense cold and wind chill in these climates is frostbite. Frostbite occurs when the skin becomes so cold it freezes. Ice crystals can develop on the skin and the tissue becomes severely damaged. The parts of the body most at risk of frost bite are hands, feet, nose and ears, if frostbite becomes very serious amputation can be necessary. Another hazard of such intensely cold conditions and low precipitation totals is that water becomes frozen very easily and despite the huge amounts of frozen water (ice) in polar areas, people can become dehydrated very easily. With the absence of rain or water, people often take the risk to eat ice in order to stay hydrated. This is a hazard in itself as eating ice will reduce the core temperature of the body and can lead to hypothermia.
Exposing the body to such intensely cold climates can lead to such hazards as hypothermia, frostbite and dehydration.
c) Discuss the nature of rock weathering found in high latitude and high altitude environments.
The most widespread rock weathering process in high latitude and altitude environments is generally freeze-thaw. Freeze-thaw weathering works due to water expanding by 9% as it freezes. In cold environments such as those found in high latitude and high altitude areas water can often get trapped in cracks in rocks that then becomes frozen. As the water expands, this results in pressure exerted on the rock. If this process is continually repeated, the rock will eventually give into the pressure and crack into pieces.
The rate of this weathering can vary depending on how often the water freezes and thaws. For example in extremely high latitude environments, such as EF (ice cap) areas, freeze-thaw weathering will have little effect as the temperature will very rarely rise above freezing point. Because the thawing of ice in EF environments will seldom occur the rate of freeze-thaw weathering is very low.
In mountainous regions (high altitude) such as the Alps the air temperature will often fluctuate between below freezing over night and temperatures just above freezing in daylight hours (diurnal freeze-thaw). This increased rate of freezing and thawing results rocks cracking under the pressure at a much quicker rate than those in extreme polar environments such as Antarctica. Evidence of the huge effect that freeze-thaw weathering has on mountainous regions is the numerous scree slopes that can be seen in these areas.
Although freeze-thaw is by far the most effective and widespread form of rock weathering in these environments there is a few examples of plant root weathering in lower mountainous areas, but few high altitude and high latitude areas can maintain larger plants life. Also in lower mountainous areas a little acid rain weathering can also occur.
