At present the Corona crisis is very severe. Many people die from the virus. The damage to the economy is huge. Nonetheless, I want to write on another problem of mankind, the climate change. I have read a German book on this subject by two climatologists from Potsdam, Rahmstorf and Schellnhuber. They report on a large consensus in science that the global warming is caused by man. Doubling the amount of carbon-dioxide in the atmosphere would mean a temperature rise of 3 Kelvin (+/- 1 K at a confidence level of 95%.) Those who want to know more are advised to read the reports of the IPCC (Intergovernmental Panel on Climate Change.) I think their scientific arguments should be taken seriously, as well as their concern to use the knowledge of our time in a responsible way.