The polar type of climate and vegetation is found mainly north of the Arctic Circle in the northern hemisphere. The ice caps are confined to Greenland and to the highlands of these high-latitude regions, where the ground is permanently snow-covered.The lowlands, with a few months ice-free, have tundra vegetation. They include the coastal strip of Greenland, the barren grounds of northern Canada and Alaska and the Arctic seaboard of Eurasia.
In the southern hemisphere, the virtually uninhabited continent of Antarctica is the greatest single stretch of ice cap where the layers of permanent ice are as thick as 3 000 m (10 000 feet).
1) Temperature: The polar climate is characterised by a very low mean annual temperature and its warmest month in June seldom rises to more than 10°C (50°F). In mid-winter (January), temperatures are as low as -37°C (-35°F) and much colder in the interior. Normally, not more than four months have temperatures above freezing-point! Winters are long and very severe; summers are cool and brief. Within the Arctic and Antarctic Circles, there are weeks of continuous darkness. At the North Pole, there are six months without light in winter. Despite the long duration of sunshine in summer, when the sun does not set, temperatures remain low, because the sun is low in the sky and much of the warmth of its faint rays is either reflected by the ground snow or used up in melting the ice. It has little power left to raise the air temperature. Water in the soil is frozen to great depths thereby called permafrost and the summer heat can only thaw the upper 150 mm (six inches) of the soil. The ground remains solidly frozen for eight months, and is inaccessible to plants. Frost occurs at any time and blizzards, reaching a velocity of 209 km (130 miles) an hour, are not infrequent. They can be very hazardous for the polar inhabitants. In coastal districts, where warmer water meets cold land, thick fogs may develop. They last for days and in many instances, it is not possible to see for more than a few metres.
2) Precipitation: Precipitation is mainly in the form of snow, falling in winter and being drifted about during blizzards. Snowfall varies with locality; it may fall either as ice crystals or large, amalgamated snowflakes. As it takes 250-300 mm (10-12 inches) of snow to make 25 mm (1 inch)of rain, precipitation in polar regions can be expected to be light, not more than 300 mm (12 inches) in a year. Convectional rainfall is generally absent because of the low rate of evaporation and lack of moisture in the cold polar air. There is normally a summer maximum, and the precipitation is then in the form of rain or sleet.
In regions where winds blowing out from the large anticyclones developed over the ice caps are prevalent, rain comes in summer, when more evaporation is possible. But in coastal areas, where cyclones are more strongly felt, the tendency is towards a winter maximum, for that is when cyclonic activity is greatest. In such regions, the annual rainfall of 250 – 300mm(1012 inches) for the tundra may be exceeded.Much heavier rainfall has been recorded, especially in areas where the cyclones are most frequente.g. Jan Mayen (71°N, 8°W) has 381 mm (15 inches), Vardo (70°N, 31°E) has 660 mm (26 inches) and Angmagssalik (66°N, 38°W) has over 940mm (37 inches).
Fig. 27.2 shows the rhythm of temperature and precipitation of a tundra region taken at Upernavik, Greenland (72°N, 56°W). Its winter temperature is -22°C (-8°F) while its warmest month in July is only 5°C (41°F), giving an annual range of 27°C (49°F). Precipitation is low, only 231mm (9.1 inches), falling mainly in the second half of the year, both as rain and snow.
In such an adverse environment as the tundra, few plants survive. The greatest inhibiting factor is the region’s deficiency in heat. With a growing season of less than three months, the warmest month not exceeding 10°C (50°F) (the tree-survival line) and an annual precipitation of only 254 mm (10 inches), there are no trees in the tundra. Such an environment can support only the lowest form of vegetation, mosses, lichens and sedges. Drainage in the tundra is usually poor as the sub-soil is permanently frozen. Ponds and marshes and waterlogged areas are found in hollows.
In the more sheltered spots, stunted birches, dwarf willows and undersized alders struggle for a meagre existence. Climatic conditions along the coastal lowlands are a little more favourable.
Here one can find some hardy grasses and the reindeer moss, which provide the only pasturage for the herbivorous animals like reindeer. In the brief summer, when the snow melts and the days are warmer and longer, berry-bearing bushes and Arctic flowers bloom. Though short-lived, they brighten the monotonous tundra landscape in ‘Arctic prairies’. In the summer, the tundra is full of activities. Birds migrate north to prey on the numerous insects which emerge when the snow thaws. Mammals like the wolves, foxes, musk-ox, Arctic hare and lemmings also live in the tundra region.
Human activities in the tundra are largely confined to the coast. Where plateaux and mountains increase the altitude, it is uninhabitable, for these are permanently snow-covered. The few people who live in the tundra live a semi-nomadic life and have to adapt themselves to the harsh environment.
In Greenland, northern Canada and Alaska live the Eskimos, numbering less than 28 000 today. They used to live as hunters, fishermen and food-gatherers, but in recent years, more and more of them are settling in permanent huts. The Polar Eskimos, living around Thule in north-west Greenland, still lead an uncertain life, not very much different from their forefathers. The seasonal changes in climate necessitate a nomadic way of life. During winter, they live in compact igloos and in summer, when they move out to hunt, they pitch portable tents of skins by the side of streams. Their food is derived from fish, seals, walruses and polar bears. Other Eskimos hunt caribou (the name given to reindeer in America) and other animals to secure a steady supply of their daily meat, milk, fat, skins and bones.
In the last fifty years, through their contact with the Europeans, the way of life of the Eskimos has undergone tremendous changes. Coastal villages have permanent wooden houses complete with modern facilities; speedboats are replacing frail kayaks. Deadly rifles instead of traditional harpoons are used to track down animals and seals. Fur-bearing animals are being reared on a commercial scale, and fishing, too, is being commercialized. In some more accessible parts of Canada and Alaska, schools have been established, and the Eskimo children are being taught the skills which will allow them to fit into the modern way of life.
In the Eurasian tundra are other nomadic tribes such as the Lapps of northern Finland and Scandinava, the Samoyeds of Siberia (from the Ural Mountains and the Yenisei basin), the Yakuts from the Lena basin and the Koryaks and Chuckchi of north-eastern Asia. They wander with their herds of reindeer across the Eurasian tundra where there are pastures. Many of them have taken to a more settled life. In the Russia, large farms have been established for raising reindeer and for breeding fur-bearing animals.
The importance and Recent Development of the Arctic Region
The Arctic region, once regarded as completely useless, is now of some economic importance. Apart from the efforts of the various governments in assisting the advancement of the Arctic inhabitants, the Eskimos, Lapps, Samoyeds etc ., new settlements have sprung up because of the discovery of minerals. Gold is mined in Alaska, nickel near Petsamo, Russia, petroleum in the Kenai Peninsula, Alaska, and copper at the Rankin Inlet, Canada. The Alaskan oil pipeline brings crude oil from the Alaskan oilfields to northwest U.S.A. In like manner, gas is transported from the interior of Siberia to the countries of Europe including European Russia. Coal has been mined in Spitsbergen for a long time and also in Alaska. With the declining reserves of iron ore around Lake Superior, the Great Lakes industrial concerns are using more and more iron from large iron ore deposits in Labrador. New railway lines have been constructed to bring the ore to the St. Lawrence River for subsequent shipment to the major industrial districts. Rich deposits of iron ore at Kiruna and Gallivare in Sweden have made it possible for Sweden to enjoy a prosperous export trade in iron and steel and other metallurgical products.
With the establishment of ports on the Arctic seaboard of Eurasia, it is now possible to ship timber and fur from Siberia. Though the ports, such as Igarka at the mouth of the Yenisei, are not ice-free, modern ice-breakers keep the passage open most of the time. On the Arctic lowlands where the growing season is lengthened by warm currents or higher temperatures, experiments have been carried out to devise varieties of hardy cereals for local needs. It may not be long before the tundra is brought under greater agricultural, especially pastoral use. The healthy air and its preservative qualities (it is practically germ-free) are factors worth considering for future colonization. Scientists, meteorologists and explorers have lived in the Arctic and Antarctica, making studies of their geology, weather conditions, plant and animal life that will be of great significance in years to come.