Is the Earth getting warmer or colder?

Many scientists think that the earth is getting warmer, and this is because of the Greenhouse Effect. There are some scientists, however, who believe that the opposite is happening—the earth is getting colder. There is, as we know, a lot of carbon dioxide in the atmosphere. It comes from the oil and coal which we are using and the rainforests which we are burning. But this also causes a lot of dust. This dust mixes with the moisture in the atmosphere and creates a mist, a bit like the pollution over a large city. This mist blocks out the warmth of the sun, and as a result the earth will be colder. Ice will cover the northern hemisphere at least as far south as London, England. But the scientists have thought of some unusual ways to prevent a new Ice Age. One of their ideas is to spread large sheets of black plastic over the Polar ice caps. The black surface will absorb the heat from the sun and the ice will melt. Of course, if the scientists aren't careful this will have the same result as the Greenhouse Effect—coastal cities like New York, Bombay, London and Sydney will be under water.

In fact, since it is the burning of fuel sources such as oil, wood and coal which is the reason why the earth is getting warmer or cooler, all the scientists agree that any change in temperature will be temporary. By the year 2100 the temperature will be back to normal—because by then there will be no more natural sources of energy!

Text 3.16

THE GREENHOUSE EFFECT

Noticed anything strange?

Have you noticed any change -in the weather in your country recently? In 1987 a hurricane hit southern Britain and parts of north-western Europe for the first time in centuries. In 1990, very strong winds "caused enormous damage again in the same region. In 1988, Arizona had its first White Christmas ever, while 1990 was the third year that there was very little snow in the Alps. Countries like Ethiopia find it more and more difficult to grow enough food because there is never enough water, but in places like Bangladesh, there's too much and floods happen more and more often.

Who's to blame?

Are we the cause of this change in the weather? Will it get worse? Can we do anything to stop it? If we can do something, will we do it? And will we do it in time? The answers to these questions are: possibly, probably, certainly, probably not, certainly not.

What's the cause?

Firstly, there's too much carbon dioxide. These days we're burning more coal and oil in cars, factories and power stations and this creates carbon dioxide. Carbon dioxide and other gases like CFCs stop the sun's heat from escaping into space. The atmosphere gets warmer and causes strange weather conditions like hurricanes. The ice cap melts, the sea level rises and this causes floods. Secondly, there are fewer trees; we're cutting down huge areas of forest in different parts of the world. Trees need carbon dioxide, but with fewer trees there's more carbon dioxide. A very simple description of global warming — the greenhouse effect.

And what will happen?

It's 2090. There are more islands in the British Isles because parts of the country are under water, including a large area of London. Southern England is world-famous for its wines and you can often see lions and elephants in Devon and Cornwall. It's warm, about 30°C, but it's often cloudy and it rains a lot. Venice no longer has a tourist problem because Venice now lies under several metres of water. So do New Orleans and Shanghai. Washington is in a desert region. The sand on beaches on the Atlantic coast and in Australia has mostly disappeared. More and more people are starving because there isn't enough water to grow crops in the USA, and while Canada, Scandinavia and Siberia all have enough rain, the soil is poor and doesn't produce enough food. The Sahara now covers most of north and central Africa.

Text 3.17

ENVIRONMENT AND DEVELOPMENT: A GLOBAL CRISIS IN THE MAKING

ATMOSPHERE

Chemical pollution is changing the structure of the earth's atmosphere. The damage air pollution causes-to human health, agriculture, forest growth, water resources, and human-made structures-has a real cost.

Concern for human and economic health has sparked national and international action on several interrelated fronts: against ozone-layer destruction, global warm­ing and acid rain.

SOIL

We are losing ground in our struggle to feed the hungry. Every year 15 million acres of farmland are lost forever, while another 50 million acres-an area the size of Kansas-lose their productive capacity.

TROPICAL FORESTS

Tropical forests are disappearing at the rate of nearly an acre a second or 3,000 acres an hour. Tropical forests are the source of half our medicines, as well as other products. They regulate climate and prevent floods and landslides. In the tropics, 10 trees are being cut for every one planted; in Africa the rate is 29 to one.

WILDLIFE

In the next 30 years, unless drastic steps are taken, we will preside over a holocaust that could remove one quarter of the plant and animal species from the face of the earth. Most will die unknown. The main cause of extinctions is habitat destruction, especially in tropical forests, which are being destroyed at a rapid rate.

WATER RESOURCES

More than 97 percent of all water on earth is sea water, and most of the world's wastes-some 20 billion metric tons a year-end up in our oceans, generally in coastal waters, where they interfere with fisheries, development and recreation.

Just one percent of the world's fresh water is available for human use; the rest is frozen in glaciers and ice caps. If managed efficiently, there would be enough for everyone, but unequal distribution, contamination and waste are threatening pres­ent and future supplies.

Nearly two billion people have inadequate drinking water, and three billion lack proper sanitation. Arsenic, barium, cadmium, mercury, lead and other pollutants in US drinking water are responsible for health problems ranging from stomach dis­orders to cancer, birth defects and neurological, kidney and liver damage.

DEVELOPMENT

The process of development in western countries is now seen as a major source of environmental degradation, especially pollution of the atmosphere, land and water. Chemicals once hailed as advances are now having serious repercussions on human health and the health of the planet. Rapidly growing populations are using more of the earth's limited resources.

ENVIRONMENT AND DEVELOPMENT:

SOLUTIONS