Our fragile planet

Tornadoes, sometimes called "twisters", are whirlwinds with speeds of up to 400Km per hour. In the USA, there are 1.000 tornadoes every year. They look fascinating and dramatic TV, but they can kill.In Britain, there were very few tornadoes in the past. Now, there are more than 50 tornadoes a year.

Tornadoes are only one sign of the world's climate changes. There are many others. The number of thunderstorm is increasing and there are more hurricanes. There are more floods in some parts of the world, and there's much less rain in others. We know that these things happen because global temperatures are rising and many people believe the future. The problems of climate change won't go away unless we do something about the causes.

Scientists still

do not know enough about the reasons for these temperature changes. Some say that these types of climate changes are natural, but most scientist think human activity is the problem. Cutting down trees, burning too much oil, and the increase in the number of cars and planes are some of the things that cause the problems.

Scientists belive that if the temperatures continue to rise, the ice at the poles will melt. If the ice melts, sea levels will rise. Some islands in coastal cities. All this means that unless we do something to stop global warming now, there may be many other dramatic changes in the future.