Across
- 3. the whole of space and everything in it, including the earth, the planets and the stars.
- 6. a gradual increase in the overall temperature of the earth's atmosphere generally attributed to the greenhouse effect caused by increased levels of carbon dioxide, CFCs, and other pollutants.
- 8. the salty water that covers a large part of the surface of the earth.
- 11. a situation in which a plant, an animal, a way of life, etc. stops existing.
- 12. there are more people living in an area than can be supported properly.
- 13. animals, birds, insects, etc. that are wild and live in a natural environment.
- 14. large natural area where trees grow close together.
Down
- 1. to treat things that have already been used so that they can be used again.
- 2. the act of cutting down or burning the trees in an area.
- 4. a change in global or regional climate patterns, in particular a change apparent from the mid to late 20th century onwards and attributed largely to the increased levels of atmospheric carbon dioxide produced by the use of fossil fuels.
- 5. existence of a variety of plant and animal species living in their natural environment.
- 7. a very large sea mammal that breathes air through a hole at the top of its head.
- 9. the trapping of the sun's warmth in a planet's lower atmosphere, due to the greater transparency of the atmosphere to visible radiation from the sun than to infrared radiation emitted from the planet's surface.
- 10. the process of making air, water, soil, etc. dirty and not safe for living creatures.