Global warming refers to the increasing temperature of the Earth. A warmer Earth may lead to changes in weather patterns, a rise in sea level, and have a serious effect on plants and animals, including humans.

Global warming is caused by humans releasing too many greenhouse gases into the air. Although greenhouse gases occur naturally, many of the things that humans do also produce them. Too many greenhouse gases in the atmosphere trap too much energy from the Sun, and cause the Earth's temperature to rise.

In the last 100 years, the Earth's temperature has increased by about 0.5°c. Although this doesn't sound like much, 0.5°c can have a great effect on the Earth. Scientists think that this increase is mainly due to the greenhouse gases humans have produced. So how do we produce these greenhouse gases?