CLIMATE CRISIS

Holes in the sky

This satellite photograph shows the hole in the ozone layer over Antarctica. The hole is pink and white on this computer photograph. The ozone layer stops some of the ultraviolet radiation from the sun. Ultraviolet radiation causes a suntan. Too much ultraviolet radiation causes sunburn and skin cancer.

CFCs (chlorofluorocarbons) in the atmosphere have caused the hole. Scientists first discovered the hole in 1982, and it is getting bigger.Thirty per cent of CFCs come from aerosol cans, thirty per cent from fridges and air-conditioning, and thirty-four per cent from the manufacture of some plastic products.

The greenhouse effect

• Sunlight gives us heat. Some of the heat warms the atmosphere, and some of the heat escapes back into space.

• During the last 100 years we have produced a huge amount of carbone dioxide. The carbon dioxide in the atmosphere works like the glass in a greenhouse. It allows heat to get in, but it doesn't allow much heat to get out. So the atmosphere becomes warrner because less heat can escape.

Where does the carbon dioxide come from? People and animals breathe in oxygen and breathe out carbon dioxide. Trees take carbon dioxide from the air, and produce oxygen. We produce carbon dioxide when we burn coal, oil, petrol, gas or wood. In the last few years, people have burned huge areas of rain forest. This means there are fewer trees, and, of course, more carbon dioxide.

A hotter earth?

Some scientists think the greenhouse effect will make the world hotter. Areas near the coasts will be cloudier and wetter. There will be more storms. Inland areas will have a little more rain, but because the temperature will be higher, they will be drier. Sea levels will rise. They have already risen by 15 cm since 1880. Maybe they will rise another 30 cm before 2030. But clouds reflect sunlight back into space, and maybe more clouds will make the carth cooler again. Is the world's climate changing? We don't know.

Some facts about climate

• Between 1980 and 1990 the temperature of the North Atlantic rose by 1°C.

• Alaska had the coldest winter ever in 1988.

• In the 1980s there were terrible floods in Bangladesh and India.

• Africa had droughts and famines during the 1980s. Deserts became larger.

• Britain and France had hurricanes in 1987 and 1990. Hurricanes are very rare here. The strong winds destroyed millions of trees.

• In 1990 the American Government decided to plant three billion trees - in one year!