Unlike other planets, the earth is surrounded by a layer of atmosphere which protects us from most of the sun's harmful ultraviolet radiation and controls the temperature on earth.

Although the sun is 93 million miles away, its harmful rays could destroy our planet if the atmosphere wasn't there to protect us.

This protective layer of atmosphere is very thin: it needs to be so that heat from the earth can escape. In fact, if the world was the size of an apple, the atmosphere would actually be thinner than the apple skin!

But we humans are making this vital layer of atmosphere thicker. When we release gases like Carbon Dioxide (CO2) by burning fossil fuels (fuels like petrol, oil and gas, made from the very ancient remains of dead plants and animals) and as we cut down forests and replace them with farmland, this has the effect of trapping in heat and raising temperatures. This can result in extreme weather conditions which will affect the lives of all creatures, including us humans.

Creatures such as Polar Bears are already in trouble because Global Warming is melting their Arctic habitat.

Throughout the Earth's history, the climate has changed naturally for many different reasons, but this time, we are directly contributing to a change. Humans are responsible for most of the CO2 gas that is being pumped into the atmosphere every day.