Carbon dioxide is a gas that occurs naturally in the atmosphere. As plants
grow, they absorb carbon dioxide, which is combined with water to create
simple sugars. These are then turned into more complex compounds that form
the structure of the plant. Energy for this process (photosynthesis) comes
from the sun.

When a plant dies, is burned or is eaten by animals, the carbon dioxide
is released back into the atmosphere. The carbon cycle helps create a stable
environment for all living things, including us!
Prehistoric forests absorbed millions of tonnes of carbon dioxide from
the atmosphere. As the planet changed, the forests were buried under the
ground, with the carbon trapped in the trees.

Over millions of years, heat and pressure turned the trees into oil, coal
and gas. In the last hundred years, we have used half of the planet's fossil
fuel reserves for energy and transport - rapidly releasing millions of tonnes
of carbon dioxide back into the atmosphere.

There are not enough plants on the planet to absorb all this extra carbon
dioxide gas, so it escapes into the atmosphere. The carbon dioxide lets
sunlight through, but reflects heat back onto the surface of the earth.
This is causing the planet's temperature to slowly increase.
Global warming may result in rising sea levels, coastal erosion and floods.
It may cause drought, leading to water supply problems and crop failure.
It may also lead to extreme weather, such as storms and hurricanes, which
cause severe damage to buildings, roads and infrastructure (communications,
water and electricity supplies).

To slow down climate change, all countries in Europe have agreed to reduce
energy use to decrease the amount of carbon dioxide they produce. They
will also increase use of renewable energy sources.
To find out more about climate change and how you can help reduce carbon
emissions, visit our transport, web
links, photo gallery and video
pages.