Climate change is one of the greatest environmental, social and economic threats facing the planet.

According to the Third Assessment Report of the Intergovernmental Panel on Climate Change (IPPC) that brings together the world's leading experts in this field, the globally averaged surface temperature is projected to increase by between 1.4 and 5.8°C from 1990 to 2100 under business-as-usual, and sea levels are expected to rise by between 9 and 88 centimetres over the same period. If nothing is done to reduce these changes, they will have major consequences for the ecosystem and our economies.

These consequences will include geographic shifts in the occurrence of different species and/or the extinction of species. Changes in rainfall patterns will put pressure on water resources in many regions, which will in turn affect both drinking water supplies and irrigation. Extreme weather events and floods will become more frequent with their well-known economic costs and human suffering. Warm seasons will become dryer in most mid-latitude continental interiors, increasing the frequency of droughts and land degradation. This will be particularly serious for areas where land degradation, desertification and droughts are already severe. Developing countries will suffer particularly, and tropical diseases will extend their geographic range. Globally, the 1990s were the warmest decade since 1861.