The atmosphere is the layer of gases that surrounds the Earth.  It's made up of gases including nitrogen, oxygen, argon, carbon dioxide, water vapour and small amounts of other gases.

The gas that has the most effect on our climate is carbon dioxide.  Carbon dioxide is what we call a greenhouse gas.  This is a gas that traps energy from the Sun in the form of heat, warming the Earth.  The more greenhouse gases in the atmosphere, the warmer the Earth is.

Carbon dioxide and the other greenhouse gases have been part of the Earth's atmosphere since the dawn of time.  We actually need some greenhouse gases otherwise the Earth would be too cold for us to live here.

Since the Industrial revolution (in about 1750) the amount of carbon dioxide in the atmosphere has gone up by about a third, and is still rising each year.  This is mainly due to the fact that people burn oil, gas and coal, which have put our natural carbon cycle out of balance. The amount of carbon dioxide in the air is likely to be higher now than it has been for twenty million years.

Have another look at the picture above.   The pink ball shows how big our entire atmosphere would be if it was rolled up into a ball.  It makes it easier to see that we can have a big impact by changing what goes into it.  Picture from CarbonSense.

Myth nine - there's no point in me taking action