Across
- 3. A radio wave of a wavelength above one kilometre
- 4. Capable of being renewed
- 7. All the liquid water on the Earth's surface
- 9. A layer of ice covering an extensive tract of land for a long period of time
- 10. Having a wavelength just greater than that of the red end of the visible light spectrum but less than that of microwaves
- 12. The land masses on Earth
- 13. Areas on Earth where the temperature in layers of soil or rock beneath the surface never rises above freezing point
- 17. An extreme of the Southern Oscillation that causes drought in parts of Australia
- 18. A colourless, odourless gas produced by burning carbon and organic compounds and by respiration
- 19. A colourless, odourless flammable gas which is the main constituent of natural gas. It is the simplest member of the alkane series of hydrocarbons
- 20. The warming of Earth caused by greenhouse gases
- 21. Periods between glaciations
- 24. The process of becoming a vapour
- 26. Fuels that contain the carbon of plants and animals that died and were preserved millions of years ago
- 27. The chemical element of atomic number 7, a colourless, odourless unreactive gas
Down
- 1. The long-term averages of weather conditions
- 2. The process by which carbon is recycled through the soil, water, living things and the atmosphhere
- 5. All living things on Earth
- 6. The conditions in the atmosphere
- 8. The production and discharge of something, especially gas or radiation
- 11. The state of being clear of trees
- 13. The process by which green plants and some other organisms use sunlight to synthesize nutrients from carbon dioxide and water
- 14. The term thermohaline circulation refers to a part of the large-scale ocean circulation that is driven by global density gradients created by surface heat and freshwater fluxes
- 15. The conversion of a vapour or gas to a liquid
- 16. A biological community of interacting organisms and their physical environment
- 22. The emission of energy as electromagnetic waves or as moving subatomic particles, especially high-energy particles which cause ionization
- 23. The layers of gasses surrounding the planet
- 25. A fuel derived immediately from living matter