POLAR AND TUNDRA REGIONS -----ENVIRONMENTAL ISSUES

POLAR    AND    TUNDRA       Environmental Issues

The Arctic region has many minerals that are important to people like: iron, gold and oil. People live and work in the Arctic to remove these valuable minerals and sell them but this has its advantages and disadvantages:

Advantages	Disadvantages
The oil and gas bring money to the region. Jobs are provided for local people and migrant workers from different countries. It provides power for the local people.	Forests which have taken a long time to grow are destroyed by the building of roads and pipelines. More pollution is released into the atmosphere, increasing the acidity of rain. Acid rain can damage soils and kill trees. There is a danger of a big oil spill or gas explosion

POLAR AND TUNDRA REGIONS----- PEOPLE

PEOPLE

Only a few thousands people live in the tundra regions. The Inuit live in northern Canada, Greenland and Alaska. The Lapps (or Sami) herd reindeer in northern Scandinavia in an area nicknamed Lapland.

Traditionally, the Inuit were hunters and fishermen: in winter they fished for seals below the ice and in summer they hunted for caribou on the land. They travelled by sledge and built temporary ice shelters called igloos.

To help them survive in the cold, stormy weather, they had to wear thick, warm clothes like coats and salopettes (trousers) which are waterproof and have fur inside to insulate them.
Their boots had special tennis racket-like soles so their body weight was spread out and they didn't sink in the soft snow.
Despite it being freezing, the sun is always shining so the Inuits had to wear tinted goggles and a mask to stop them going snow blind.

Today, many Inuit dress in modern clothes. Some have motor-powered snowmobiles and live in homes made of modern materials. Some homes have: electricity, double-glazed windows and telephones. Heated houses have to be built on stilts so that the permafrost does not thaw. If it did, the ground would give way. Water pipes are insulated and run above ground to stop them freezing.

Modern foods and other goods are flown into the towns to be sold in supermarkets so living costs are now high. Imported food has created health problems for the Inuit as it is rich in carbohydrates and sugar not found in their traditional diet

POLAR AND TUNDRA REGIONS---- PLANTS

PLANTS

The plants growing in the tundra are often small and grow close to the ground: Lichen is a plant that is a mixture of both fungus and an alga. It grows well without soil, even on bare rock. It is an important food for creatures like reindeer, which dig underneath the snow-covered soil to find it.  Mosses are flowerless plants that grow very close to the surface of the ground, forming a soft, spongy cushion. They have tiny rootlets that absorb moisture and minerals. Many plants have dark red leaves so they can absorb as much heat from the sun in the cold tundra climate as possible.

POLAR AND TUNDRA REGIONS ----- GEOGRAPHY

ANIMALS

In the Arctic, many animals live on land, while in Antarctica, life is mainly based in the surrounding waters.  Animals in both polar regions have had to adapt to survive in the extreme cold: Polar bears: are white to help them camouflage (hide) easily in the snow from hungry predators, have large paws to help them grip the ice and have thick fur to help them keep warm. Reindeer (also called caribou) feed on grasses and plants in the tundra in the summer and then travel (migrate) south in winter to warmer places. The underside of each hoof is hollowed out like a big scoop and allows them to dig through snow in search of food. They also use their hooves to paddle through chilly northern rivers and lakes. Musk oxen have a fine layer of wool under a thick outer coat. They crowd together so water vapour in their breath forms a cloud to trap heat. Arctic foxes have white fur in the winter to help them blend in with the snow - they then shed this for a brown one as the snow melts in the summer. They have a long, bushy tail which they use to keep their nose and feet warm when asleep too. Walruses have sharp tusks to help protect them from polar bears and use special air sacs in their neck to help them keep their head above water when swimming. Penguins (that only live in Antarctica): have dark feathers on their backs to absorb heat from the sun and have lots of blubber (fat) under their skin to help insulate their bodies. They also huddle together with other penguins to keep warm. Weddell seals live further south than any other mammal. They have grooves in their teeth to help them break holes in the Antarctic ice and can swim underwater for over an hour to look for food.

POLAR AND TUNDRA REGIONS --- CLIMATE

CLIMATE

The polar regions are very cold because the Sun's rays are weakest at the North and South Pole. Powerful, icy-cold winds blow throughout the year. Often the wind sweeps up powdery snow from the ground and swirls it around, causing cold blizzards. Very little new snow or rain falls as it is too cold for moisture to evaporate. The wind chill can make the temperature appear even lower than it actually is. An actual temperature of -6oC, for example, would make it feel a bitterly cold -34oC when the effect of wind chill is added on. Temperatures as low as -50oC have even been recorded. The ground in the Tundra regions around the edge of the Arctic stays frozen for nine months of the year. In the summer months, only the surface thaws and deeper ground stays frozen. This frozen layer is called permafrost. Melted snow cannot seep through the permafrost so, in the summer, the surface of the tundra lands becomes boggy. The landscape of the tundra is therefore a treeless plain covered with moss and some grass-like plants.

POLAR AND TUNDRA REGIONS --- AREAS AND POSITION

Polar and Tundra Regions

The polar regions are the coldest places on Earth: Antarctica is at the South Pole and is a continent of ice-covered rock; the Arctic is at the North Pole and consists of a frozen ocean, surrounded by a vast expanse of tundra - tree-less plains. The Arctic and Antarctic circles are lines of latitude going around the Earth that mark the outer limit of the two polar regions. They are found at 66oN and 66oS of the Equator. Inside these circles, the tilt of the Earth causes long summer - and short winter - days to occur. At the poles themselves, six months of unending sunlight alternate with a six-month period of darkness. Many places within the Arctic circle are nicknamed 'the Land of Midnight Sun' because the sun hardly ever disappears and it can be daylight for nearly 24 hours in the summer. The night skies in the polar regions can be filled with gently rolling coloured lights. In the Arctic they are called the Aurora Borealis and in Antarctica they are called the Australis. They are formed as solar winds hit the Earth's magnetic field and release light particles.

DESERTS --- ENVIRONMENTAL ISSUES

THE   HOT   DESERTS --- ENVIRONMENTAL   ISSUES

The desert areas are growing in size due to a process called desertification. This happens because: land has dried up as the Earth's climate has warmed; less rain has fallen, killing trees and grasses on the edges of deserts; overgrazing of animals has meant the land has become bare; an increase in population has forced people to grow crops on unsuitable land, making it become exhausted and prone to soil erosion. As it becomes harder for people find food and water in the deserts, widespread famines and droughts can occur. In Somalia in Africa, 2 million people were forced to leave their homes and become refugees in the neighbouring country of Ethiopia to survive a drought in 2011. In Egypt, the Aswan High Dam was built in the early 1900s to provide irrigation for the local farmers and many people have built their own anti-sand shields to stop dunes from spreading.

DESERTS ---- PEOPLE

THE   HOT   DESERTS

Only 5% of the world's people live in desert areas. Many live in groups or tribes and are nomads, travelling from place to place in search of: food, water and fresh grazing for their animals. Examples include the Bushman people living in the Kalahari desert and the Bedouin nomads from Arabia. Image Credit: Edward Wachtman Others live in small, fertile areas called oases. Oases form around springs or well where people can settle permanently. In the Sahara and Arabian desert, the date palm is a major oasis crop. Its: broad leaves as used for roofs; dates are eaten as a nutritious fruit; trunk is used for building with. Many people live in round tents in the desert, called yurts. They are made by putting up felt and animal hides on a wooden frame. Desert people have learnt ways to help them survive in the desert climate - they know which plants contain water and wear long, loose clothing to protect them from the heat and dust.

DESERTS -- PLANTS

  THE   HOT   DESERTS -----PLANTS

Those plants that do grow in deserts have special ways of surviving in the dry climate with very little water: Cacti - which are only fond in American deserts - are a type of succulent plant because they store large amounts of water in their thick, fleshy stems when it rains. They have spines instead of leaves because spines allow less moisture to escape. The tallest are saguaros which can reach 15m tall and live for 200 years. Some desert plants only grow when it rains. Their seeds may lie dormant, or inactive, in the ground for years, just waiting. When rain comes, they: grow, flower and die within a few days. The century plant, for example, produces just one flower in its lifetime. Trees such as the acacia have leaves pointing upright to protect them from the intense sunlight and have developed a resistance to fire. Many desert plants have long, shallow roots which spread out over a wide area. The roots absorb any rain which soaks into the ground. Their leaves are always very small, to minimise water evaporation from their surfaces. When it does rain, deserts are often scattered with bright flowers.

DESERTS --- ANIMALS

THE  HOT   DESERTS  ---- ANIMALS

Desert animals need to keep their bodies as cool and moist as possible. Many only come out at night when the desert cools down and have special features and types of behaviour to help them live more easily in the hot, dry desert conditions during the day: carnivores like the desert fox take in moisture from the blood of their prey; many desert animals like the jerboa have long ears, which lose heat easily; the elf owl nests in the stem of a cactus; geckos have tough, scaly skins to protect them from the sun and have webbed feet to help them move across the sand; the red kangaroo can keep itself cool by licking the fur on its arms; the ground squirrel can use its large, bushy tail as a sun umbrella; termite nests point north-south so only a small area faces the general direction of the sun. There are two types of camel - a dromedary has one hump on its back and a bactrian camel has two humps. They: can drink 100 litres of water at a time, then survive for up to a whole week without another drink; have no fat under their skin to keep them cool - it is stored in their hump(s) instead; have long eyelashes and hairs in their nose to protect them from dust storms; have wide, padded feet to stop them sinking into the sand.

DESERTS ---- CLIMATE

THE    HOT   DESERTS ---- CLIMATE

Clouds hardly ever form in deserts because the air is so warm that it can hold lots of water vapour without it condensing. This makes rain very rare. The Atacama desert in northern Chile is the driest desert on Earth. Parts of the desert had no rain for 400 years, from 1570-1971, and in other parts, rain has never been recorded. With no clouds to block the Sun's rays, the ground becomes baking hot. Surface temperature of at least 40oC are not uncommon. At 57oC, Death Valley is the driest, hottest place in North America. Gold prospectors died there, in 1849, when they ran out of food and water on their way to the Californian goldfields - which is how the valley got its name. Nights can be very cold, though, and even frosty in winter, because cloudless skies let heat escape. Strong trade winds blow across the deserts. In sandy deserts, the wind sweeps up fine sand and causes dust storms up to 3,000m high. As sand is blown along, it erodes rocks in its path. Over many years, the rocks may be sand-blasted into weird, sculptural shapes. The total rain for the year usually falls in just two or three heavy storms. The water does not soak in straight away, but runs rapidly across the surface, sweeping up valley debris and carrying it along wide channels called wadis. Deep canyons may be formed too.

DESERTS ---- LOCATION AND AREAS

THE    HOT  DESERTS

Deserts are dry, barren areas where less than 25cm of rain falls each year. They are mostly located in tropical areas, between about 15o and 30o north and south of the Equator. Deserts are found in areas where dry winds blow across the land. These can be a long way from the sea, where moist sea winds do not reach (e.g. the Gobi desert in Asia). They can also be in areas separated from the sea by high mountains, called the rainshadow (e.g. the Atacama desert in Chile). Sandy deserts are made up of sand which has been blown from rock faces to form smooth hills called dunes. The Sahara in Africa is a sandy desert. Stony deserts are made up of bare stone, such as the Sturt Stony Desert in Australia, for example. In some places, such as Salt Lake City in the USA, large lakes have dried up, leaving behind a layer of salt crystals. World's Largest Tropical Deserts Desert  Location Area (km2) Sahara North Africa 9,065,000 Gobi China 1,295,000 Kalahari Southern Africa 582,000 Great Victoria Australia 338,500 Great Sandy Australia 338,500 There is little to protect a desert from the action of the wind. Strong winds pick up fine surface debris and blast it again exposed rock, eroding it away to form rock pillars and isolated hills - such as Ayers Rock (Uluru) in Australia.       The most common dunes found in sandy deserts are called barachans. They are crescent-shaped and may be up to 30m high. As sand is blown up one side and slips down the other, these dunes can creep forward between 10 and 50m a year and can engulf villages.