This article uses flash animations to illustrate ideas. You'll need the free flash player to view these . If you're on a modem connection they may take a little time to load, please be patient.
Our tap pouring water into a bucket with a hole is a simple way of looking at the temperature of the Earth.
The water flowing from the tap represents the energy from the Sun, the water escaping from the hole in the bucket represents the energy the Earth loses to space, and the water level in the bucket represents the temperature of the Earth.
The hotter the Earth, the more energy the Earth loses to space. If the Earth were to get more energy from the Sun the temperature of the Earth would rise, just like the water level in the bucket, until the amount of energy it's losing to space is again equal to the amount of energy it's getting.
At its simplest level, whether or not the Earth is heating up or cooling down is determined by the difference between the amount of energy the Earth is getting from the Sun and the amount of energy it is losing to space.
Since the Industrial Revolution, the increasing amount of greenhouse gas in the atmosphere has been restricting the amount of energy the Earth is losing to space - as if the hole in the bucket were partially blocked. As a result, the Earth is heating up. If we were to stop increasing the amount of greenhouse gas in the atmosphere, the Earth would eventually (in a few decades) reach a new, constant, warmer, temperature.
But how does climate relate to the weather?
< previous next > Page 2 of 9
Content last updated: 13/12/2005
About our expert
Sylvia Knight - a climate scientist - works with the climateprediction.net project, which is trying to produce the most complete forecast of 21st century climate ever attempted. She is responsible for communicating the aims and results of the experiments to as wide an audience as possible.
Sylvia has a degree in Natural Sciences and a PhD in Meteorology, and is co-author of the Open University short course Weather and Climate Modelling.
