The Earth absorbs radiation from the sun to provide heat and energy for life.  A natural layer of atmospheric gases prevents some of the radiation from escaping keeping the planet warm and habitable.  However, too much of this greenhouse gas traps the energy from the sun preventing excessive heat from escaping.  This causes global temperatures to rise called the greenhouse effect.

The planet has a natural regulation system that can cope with most changes in temperature or changes in these atmospheric gases.  Plants and the oceans, for instance, naturally absorb the carbon released from human and animal respiration and digestion, decaying vegetation, solar activity, volcanoes and fires.  Until recently the Earth has achieved a balance between this natural release of carbon, and other greenhouse gases, and their absorption.

However, the increases above these natural levels of carbon dioxide and other gases in the atmosphere are being produced by human activity, particularly through our excessive burning of fossil fuels.  Greenhouse gases, both natural and manmade, include carbon dioxide, nitrous oxide, methane and water vapour.  The Earth cannot absorb these gases at the rate they are produced.  The result is an increase in global temperatures through the greenhouse effect.