"There are traces on the earth that tell us something about the climate."

The theme of the fall series is "Do sun, wind and water have magic powers?", based on the Science Year 2026 "Future Energy". The first event dealt with the questions "Why is our earth getting warmer and warmer? And how can we measure it?" Geomathematician Prof. Dr. Volker Michel asked the large audience: "Which of you likes raisins?" And: "Which of you doesn't like raisins?" It quickly became clear that the answers are literally a matter of taste. It's different in science. Facts count there. Volker Michel showed what an average is and how it is calculated by comparing the grades of one pupil over four school years and six subjects. Average values are also needed when making statements about global warming - from many countries around the world and over many years.

Weather data has been available since around 1850, the time in which our great- or great-great-grandparents lived. According to the records, temperatures have been rising since then. Now the weather is one of those things: sometimes the sun shines, sometimes it rains. The term "weather" refers to what it looks like outside. "Weather" describes the average weather over several days and weeks. "Climate", on the other hand, stands for the average weather over many years.

Weather data has been available for around 175 years. Compared to the age of our planet, this is a very short period of time. How can we find out what the climate was like 500, 1000 or even longer ago? Michel: "There are traces on the earth that tell us something about the respective climate." The bacterium Thaumarchaeota has lived in the sea for a very long time and has a fat layer. If the bacterium dies, it falls to the seabed. The oldest bacteria are therefore at the bottom. Michel: "Depending on whether it was warm or cold, the fatty layer changes." Tree slices with their annual rings also provide information about the climate of times long past. Michel: "There are many ways to find out whether it was warm or cold on earth. You can also go further back in time." There are warm and cold periods, not least because of the Earth's uneven orbit around the sun. Michel: "We should actually be back in an ice age." But the warm period was too warm. The researcher John Baptiste Joseph Fourier (1768-1830) discovered that it should actually be much colder on the Earth's surface. He assumed that the earth's atmosphere kept some of the heat donated by the sun on the earth and that certain gases formed a warming belt around the earth and did not allow some of the heat to escape to the outside. Today, this phenomenon is known as the greenhouse effect.

Air bubbles bound in snow can be found in ice cores from the Arctic and Antarctic. Michel: "You can look back up to 800,000 years." And: "There was sometimes more and sometimes less carbon dioxide on Earth." When there is more carbon dioxide in the air, it gets warmer. Carbon dioxide is produced, for example, by the respiration and digestion of living organisms and by burning fossil fuels and wood. Forests filter carbon dioxide from the

the air. The more forests are cut down, the more carbon dioxide remains in the air. Due to global warming caused by this greenhouse effect, the "eternal ice" is melting. Michel: "Without ice, it will be uncomfortable on Earth."

When the water heats up, water vapor rises. The warmer the air becomes, the more water vapor it can absorb. Michel: "This makes our weather more extreme." And: "The stronger the climate change, the worse the consequences." Solutions are renewable energies - electricity from other sources, heating without oil and gas, driving less, eating less meat.....

The children's university will also focus on hydrogen, hydropower and wind energy.