Across
- 2. long period when there is little or no rain
- 3. any energy source that encompasses all those things that do not consume fossil fuels
- 7. an increase in the amount of dioxide and other gases in the atmosphere which is believed to be the cause of a gradual warming of the surface of the Earth
- 9. energy forms formed by natural processes
Down
- 1. animals or plants which may soon not exist because there are very few now alive
- 4. 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
- 5. able to decay naturally and harmlessly
- 6. the cutting down of trees in a large area, the desctruction of forests by people
- 8. strong, unpleasant and sometimes dangerous gas or smoke
- 10. energy from the sun that is converted into thermal or electrical energy