All life on earth depends on the earth’s atmosphere. The atmosphere contains the air we need to be able to breathe. It protects us against the sun’s ultraviolet rays, and it contains a number of gases that retain the sun’s heat so that the temperature remains relatively constant. The most important gases in this respect are aqueous vapour, carbon dioxide (CO2), methane and dinitrogen oxide. Without these greenhouse gases, as they are also called, the earth would be in a permanent ice age.

Problems arise when the concentration of greenhouse gases becomes too high. As a result the temperature on earth will rise, with dire consequences.

Especially the amount of CO2 has increased sharply since we started using coal, oil and gas. There is also more methane in the atmosphere; chiefly from livestock farting and burping, but also from coal mines, rice paddies and landfill sites. The increased amount of dinitrogen oxide comes from fertilisers and various industrial gases for cooling systems, for instance.

In order to stop the upward trend in the temperature (globally about 0.75 degrees since the end of the 19th century), it is essential to reduce the emission of greenhouse gases – especially CO2.

You can read more about CO2 on the following pages and how you can help to reduce CO2 emissions.