AIR
The biggest global concern at present is "Global Warming". The earth gets hotter each year due to the build up of carbon dioxide and other "greenhouse gases" like methane in the upper atmosphere. These act like glass in a greenhouse - they let the light in but prevent the release of heat back to space. This phenomenon, also called "Climate Change", is now thought to be responsible for warmer and wetter weather in Europe.

A different problem with the air is 'Ozone Depletion'. Ozone occurs much further out than the atmosphere - in the 'troposphere'. Chemicals called CFCs, found in refrigerators, create "holes" in this ozone layer. These holes allow the dangerous rays through to earth that ozone usually blocks out. This leads to death of plankton, an essential food at the base of the food chain, and to more skin cancer.

Another impact on air is called 'Acid Rain'. This is caused by pollutants, particularly sulphur dioxide from power stations, mixing with rain particles and forming acid. This may be deposited many hundreds of miles away. The UK used to be called the "dirty person of Europe" because of the acid deposited across the rest of Europe.