For thousands of years, the concentration of carbon dioxide in the atmosphere remained much the same. But during the past 200 years it has increased steadily.
The rise in atmospheric carbon dioxide has been caused largely by:
Burning forests has two unfortunate effects:
As the concentration of carbon dioxide in the atmosphere has increased, so have mean global temperatures. This is called global warming.
Effects of global warming
Global warming could cause:
Climate change may make it impossible to grow certain food crops in some regions. Melting polar ice and the thermal expansion of seawater could cause rising sea levels and the flooding of low-lying land.
[ This page has been adapted from www.bbc.co.uk/schools/gcsebitesize/science