Environmental problems

4. an increase in the amount of carbon dioxide and other gases in the atmosphere which is believed to be the cause of a gradual warming of the surface of the Earth.
10. an extremely large wave caused by movement of the earth under the sea, often caused by an earthquake
11. damage caused to water, air.... by harmful substances or waste.
12. unwanted matter or material of any type, often that which is left after useful substances or parts have been removed.
13. the process by which land changes into desert.

1. a gradual increase in world temperatures caused by polluting gases such as carbon dioxide which are collecting in the air around the Earth and preventing heat escaping into space.
2. animals or plants in danger of disappearing forever.
3. the cutting down of trees in a large area; the destruction of forests by people.
5. the air, water and land in or on which people, animals and plants live.
6. a long period when there is little or no rain.
7. a sudden violent movement of the Earth's surface, sometimes causing great damage.
8. a large amount of water covering an area that is usually dry.
9. to collect and treat rubbish to produce useful materials which can be used again.