Unit 6, Part 1

Scientists predict British weather would get rapidly warmer and more unstable. Rising sea levels and storm surges threaten the south-east of England. Work had already started on how to replace the Thames barrier and strengthen 100 miles of sea defences around the Thames estuary, where the sea level could rise by 86cm (3ft) by 2080. The east of England is sinking at the same time as sea levels are rising - the port of Immingham, in Lincolnshire, which faces a damaging storm surge once every 50 years, can expect to be flooded for nine years out of 10 by 2080 unless sea defences are raised.

Hot summer days in the south would reach 40C. We thought we should plan how to deal with this for our children's sake, now we realise we have to do it for ourselves. This is happening in our lifetime and we must work to avoid these dangers and threats.

Winters will be mild and very wet with frequent flooding, and most of Britain will be snow-free. Even the Scottish mountains will have 90% less snow. Summers will be far hotter and drier everywhere. Crops in the south will have to grow with 50% less rain and need constant irrigation to thrive. The growing season may have to move to earlier in the year, as in Mediterranean countries, because some crops may not survive the summer heat.

By 2080 temperatures will increase by between 2C and 3.5C, depending on how much carbon dioxide is in the atmosphere, but inland in the south, away from the cooling effect of the sea, this may be as much as 5C. A very hot August, as experienced in 1995 when temperatures were 3.4C above normal, will occur every two years in three in 2080, and may be even hotter.

But while there may be bonuses for the tourist industry with weather in the south resembling the Bordeaux region of France, it is bad news for the water industry, which faces supply shortages. Summer soil moisture may be reduced by 40% making life difficult for gardeners and farmers.

But the winter rainfall will cause most problems. Deep depressions with high winds are expected to dump up to 35% more rain on Britain, leading to more frequent flooding. This combined with higher tides and sea levels could cause severe disruption in the south where most of the extra rain is expected.

More on global warming at www.guardian.co.uk/globalwarming

Unit 6, Part 2

A few degrees increase in temperature may not seem to matter much in a place where winter winds force the thermometer as low as -75C. But from plankton to polar bears, the Arctic meltdown threatens an environmental and human catastrophe. Almost every living creature in the Arctic Ocean depends on ice. Humans and polar bears hunt the whales, walruses and seals which feed around it; walruses and seals live off the shellfish and Arctic cod which eat the algae that grows under it.

Now, as the floes thin and retreat north, that delicate food chain is unravelling. It is cold and dark out there for much of the year and survival is hard. Every species depends on a short food chain. Each link in that chain is vital because, unlike temperate or tropical areas, there are no food substitutes. If anything changes, the consequences are huge. Melting threatens everything. Animals here depend on the ice. If it disappears, so will they. The stakes are pretty darn high.'

This is scant surprise to the environmentalists. Melanie Duchin, a climate change expert who visits the Chukchi Sea every year, says each time it gets harder to find the animals. 'The ice is much further from the shore and it is directly affecting wildlife.'

As the floes retreat north, animals find it harder to breed and raise their young. Warm snaps melt bear and walrus ice dens, crushing the suckling mothers and their cubs. Even if the young do survive, adult animals cannot always feed them because the further the ice retreats, the deeper the water and the harder it is to dive to the bottom where shellfish and Arctic cod live. Some animals can even find themselves trapped on land because the ice has retreated so far they can no longer swim to it. Scientists predict that, if the floes go on thinning, many species - including polar bears - could become extinct within 20 years.

It is not just marine wildlife which is at risk. On land, grizzly bears, caribou, Arctic foxes and wolves which roam the vast permafrost have finely tuned their migration habits over millions of years to coincide with the growing season of grass, moss and lichen so that they can mate and feed their young.

But as spring arrives earlier and the tundra dries out, herds are finding it difficult to travel from wintering areas in time to feed. Some 10,000 reindeer died of starvation on Russia's Chukotka peninsula two years ago and Alaska's Peary caribou face extinction.

Warmer temperatures have also sped up the reproductive cycle of land parasites like the spruce bark beetle. Plagues of the voracious bug have devastated forests on Alaska's Kenai peninsula.

An estimated 20 to 30 million spruce trees are being killed each year. Some 30 million died in 1996 alone, and the outbreak now covers more than three million acres. If the natural world is under threat in the most hostile place on Earth, the people who depend on it to survive are quick to suffer.

For centuries Eskimo fishermen on the Alaskan coast and on St Lawrence Island have harpooned whales, walruses, and seals and gathered plants to feed their families and make boats, clothes and musical instruments and to carve ivory.

Food used to be so plentiful that when one village landed a whale it shared the meat and blubber with neighbouring communities. Now Eskimos say they cannot even find enough to feed themselves and their children. A 67-year-old whaler who lives on St Lawrence Island said: 'We used to have a good life. We caught walrus and seals very much. But now we cannot find animals so easily. We go hunting for days but we do not find anything. The fishermen do not take food on their boats like the white man and after days they come home real skinny.'

Eskimos know little about the science of global warming. But they are convinced their environment is changing. March used to mark the start of spring but now the February sun melts the floes, strengthening the currents that sweep the ice edge further and further away from the coast.

Birds and insects are getting bigger. Fruits and berries they have never seen before have begun growing. If the land and water they depend on goes on warming, the people of the Arctic fear their ancient culture will die. 'We want to carry on the traditions that our grandparents, fathers and mothers showed us, but we can't,' said an Eskimo villager, who lives with his wife and seven children in a plywood house by the sea shore.

'We don't find walrus intestine and Arctic fox pelts to make special clothes. We cannot get stomach to make the drums for singing and dancing. People not have clothes, not sing, not dance.

I like traditional life, but we are suffering and people far away do not care.'