Acid rain is a mixture of water and pollutants which falls as rain and damages lakes, rivers, soils and buildings. In Sweden, about a quarter of its lakes have been damaged by acid rain, and in Germany many forests have been damaged. Buildings made of limestone in central Europe are being dissolved and statues are unrecognisable.

Acid rain can be reduced by reducing sulphur and nitrogen dioxide emissions from power stations and factories which burn fossil fuels.

The Ozone Layer

The ozone layer is the part of the atmosphere which shields the Earth from the Sun's harmful ultra-violet rays. Chlorofluorocarbon's (CFC's), which are found as coolants in fridges and in the past in aerosols, are the main cause of the "hole" in the ozone layer above Antarctica. The use of alternative chemicals would contain this threat, but the damage already caused will take a long time to heal.

Global Warming

Global warming is the slow increase in temperature of the world. The greenhouse effect is when solar radiation is prevented from leaving the atmosphere by various gases such as methane and carbon dioxide in the air. Global warming could lead to the ice-caps melting, which would raise the sea level and flood coastal areas and islands.