Climate change happens

Global warming: humans and climate change

Our planet is heating up due to global warming. This has happened several times in the history of the earth. But not at the pace of the past 200 years. Man is to blame for climate change

What is climate change?

The climate has been changing since the earth has existed. Over the course of millions of years, cold and warm periods alternated again and again. These changes were due to natural causes. When we talk about climate change these days, we mean the changes that humans have caused. In a nutshell, this means: It is man's fault that the earth is getting warmer and warmer.

How do humans influence the climate and global warming?

Primarily by using energy in almost everything he does. Machines rattle in factories. Cars run on engines. Computers and cell phones need electricity. This energy is mostly generated through combustion, for example from coal, oil or gas. This creates, among other things, the greenhouse gas carbon dioxide (CO2). The forest areas in which the CO2 could be stored are shrinking. They give way to farmland. In addition, people around the world are eating more and more meat - that too heats up the earth! Because cattle and pigs belch huge amounts of methane, also a greenhouse gas, into the air.

What do these greenhouse gases do?

CO2 and methane initially rise into the atmosphere, which is like a protective cover around our planet. Sun rays and thus warmth penetrate through them to the earth. If this gas layer is compressed by more CO2 and methane, it acts like a barrier: the heat accumulates in the atmosphere and does not return to space. The rays are reflected back to the earth, like in a greenhouse, the glass panes of which are too thick.

How many degrees does the earth's average temperature rise?

The earth's CO2 emissions were stable for around two million years. Then, a good 200 years ago, humans began to drive machines no longer through muscle power, wind or water, but - as mentioned - through combustion. This time is called industrialization. Since then, CO2 emissions have increased - and with them the temperature of the earth's surface by an average of 0.8 degrees Celsius. That doesn't sound like much, but it is enough to mess up our planet.

Global warming: what happens if the earth keeps getting warmer?

Nobody knows exactly what to expect. However, climate researchers use past data to make predictions: The seasons are changing. Winter starts later and ends earlier. In some places, heat waves become more frequent in summer. The ice on the poles is melting.

Glaciers are disappearing in the Arctic. The sea level is rising. The oceans are warming up, and more water is evaporating. This also increases the greenhouse effect, since water vapor is also a greenhouse gas. In addition, warmer air absorbs more moisture. It will rain more; stronger storms are brewing, storm surges for example.

Can humans stop global warming?

Only if he changes his lifestyle thoroughly. At the climate conferences of the United Nations, the federation of almost all countries in the world, politicians therefore decided: The average temperature must not rise more than another 1.2 degrees Celsius.

Every country should make its contribution and, for example, use more renewable energies such as solar energy, wind and water power. However, researchers doubt whether these measures are sufficient. Some even fear that the average temperature will rise by five degrees Celsius or more by the year 2100.

Many animal and plant species would then become extinct, and we humans were threatened by ever more severe natural disasters.

What can each individual do against climate change?

Above all, save electricity! And eat less meat, drive less car, fly less - or at least "make up for" the flights. You can read how, for example, here.

When islands sink

This is the Maldives - a hodgepodge of 1190 islands. Hardly any of them protrude more than a meter out of the Indian Ocean. That hasn't been a problem for the past 100 years. Now it becomes one because the sea level is rising. Researchers reckon that in 100 years it will be between 50 centimeters and one and a half meters higher than it is today.

Nobody knows whether the Maldives will then be submerged. One thing is pretty certain: Strong storm surges will rage in this region and make the archipelago uninhabitable. The government is therefore saving so that one day it can buy new land.

Where glaciers melt

120 years ago, the Roseg Glacier in eastern Switzerland looked very different: its tongue was over six and a half kilometers long. But especially at the end of the last century the ice thawed and is now two and a half kilometers shorter. In 120 years there will probably be nothing left of him, estimates Stefan Rahmstorf from the Potsdam Institute for Climate Impact Research.

Based on his predictions, our illustrators drew this and the other sequences of images in this story. In any case, the melting of the glaciers has fatal consequences. If the ice giants thaw, floods threaten in many places. In the long term, however, drought can also be the result - and the associated shortage of drinking water: Glaciers are important freshwater reservoirs that feed our rivers.

When droughts threaten

Green grass and lush leaves: it could soon be over in southern Spain. Droughts dry out the pastureland, and in spurts. These attacks accumulate. In 2005 there was so little rain that the cattle died of thirst in many places. In 2012, weather researchers recorded the driest winter in Spain in 70 years.