The natural greenhouse effect — What is it?

Few people are unfamiliar with the term "greenhouse effect" and unaware of its association with the negative consequences human intervention can have on environment and climate. Nevertheless, the greenhouse effect is first and foremost an entirely natural phenomenon. So-called greenhouse gases (which include water vapour, carbon dioxide, methane, nitrous oxide, ozone and fluorohydrocarbons) are found in the earth's atmosphere. The greenhouse gases allow incoming short-wave solar radiation to pass through unhindered on its way to the earth. On reaching the earth's surface, a small portion is reflected back, but most is absorbed before being conducted back into the atmosphere in the form of long-wave heat radiation. It is then absorbed by the greenhouse gases and released in all directions in the form of heat radiation. Thus, some of it passes into space and the rest finds its way back to earth where it contributes to global warming.

Die Erde heizt sich auf

In itself, the greenhouse effect is not just a natural phenomenon but also a very useful one. Without it, life on earth as we know it would not be possible and the average global temperature would be around -18°C instead of +15°C! If there were no natural greenhouse effect, we would be in the middle of an extreme ice age.