Climate change is caused by 'greenhouse gases', which act as an insulator within the atmosphere around the world and prevent heat from the sun escaping. Greenhouse gases include carbon dioxide, methane and nitrous oxides. Since the Industrial Revolution, the world has been burning ever increasing quantities of fuels made of carbon, such as coal, oil and natural gas. The fumes contain carbon dioxide gas and we are currently pouring almost 7 billion tonnes of this into the air each year. Nature can only remove carbon dioxide from the air very slowly, so most of it sticks around for a century or more.
Current levels of the greenhouse gases carbon dioxide and methane in the atmosphere are higher now than at any time in the past 650,000 years.
It is important to slow the warming as much as possible. This means using less fossil fuel, eliminating CFCs altogether, and slowing down deforestation.
This can be achieved best through energy conservation, including better use of public transport and cleaner, more efficient cars; and energy efficiency by greater use of gas which produces less CO2 than coal and oil, and through renewable energy such as solar power. We need to stop destroying rain forests (deforestation) and start replanting trees (reafforestation) to soak up carbon dioxide.