Do you leave the lights on when you are no longer in the room? Modern lamps consume little electricity, but it is still worth not leaving them on unnecessarily, for example when we are not in the room for a long time.

Intelligent ventilation means not too late and not too long. It is too late when we become tired from stale air, get headaches and the humidity becomes too high. It is too long when the air has already been exchanged and is cool, but we continue to ventilate and then the materials (walls, furniture) also cool down. Ultimately, heat means that things or air vibrate. When the air has been replaced but the objects and walls are still vibrating, the fresh air quickly warms up. If the walls also become cold, mould can form on them and we need expensive heating energy to get everything vibrating again. CO2 measuring devices help to ventilate at the right time and not for too long. However, these should not be useless gadgets, but perhaps used to practise one after the other in the rooms and also lent out. A nice game is to compete to see how good people's sense of timing is when it comes to ventilating at the right time and not for too long.

Long, hot showers mean water and energy consumption and ultimately high costs. The further effects are even more impressive when considered in context – did you know that long showers can be responsible for refugees and the quality of life in Germany?http://www.imodeler.info/ro?key=Ceju1XNHCFZBJc2MpbAOl5Q

Organic is extremely important for biodiversity. We have the greatest species extinction since the extinction of the dinosaurs and the consequences are greater than those of climate change. Pesticides and mineral fertilizers endanger our future. In addition, soils from organic farming usually store more carbon and thus help against the climate catastrophe. The counter-argument is often that the yields in organic farming are lower than in industrial agriculture and therefore more forests have to be cut down. This is true, for example, with cereals that are not unrestrictedly healthy. But if we eat less meat, waste less food and eat more healthy legumes, we have plenty of additional space available and can feed the entire world organically and even plant a little more forest. Organic is more expensive. But on the one hand, many costs can be saved by less meat and on the other hand, it can be bought and cooked intelligently …. of course, it is also to be questioned whether there must be such a low livelihood at all - environmental policy is also social policy.

Fortunately, tap water has long been a trend. Schools have drinking fountains and pupils bring their own water bottles, and managers also bring their water bottles to workshops. Many children are not even accustomed to unhealthy sugary drinks. Tap water is more strictly controlled than bottled drinks and saves a lot of energy and packaging. Even in motorhomes or boats, or in places where the water smells of chlorine, we can save a lot of money, energy and packaging by using good filters that are changed regularly.

Hardly anyone knows how important legumes are for saving the world. But you're probably familiar with chickpea crisps, falafel, hummus, broad bean yoghurt or even delicious lentil spread, right? Legumes are not only an alternative plant-based source of protein to animal products, but also extremely important for feeding the world. They bind nitrogen from the air in the soil and can achieve just as high yields in organic farming as in industrial agriculture with artificial fertilisers and toxic pesticides. If we harvest just as much, we don't need to cut down forests for more farmland. Legumes are also healthier than grains. In Sapiens, Harari describes how we could probably live much longer if we didn't eat so many grain products. Finally, legumes are important for bees and biodiversity. Lupins, for example, also grow in northern Germany and can be used as a meat substitute, in yoghurt, coffee substitutes, ice cream or even pasta.

Consistently separating waste, including green waste, glass and paper, is not as self-evident as can be assumed. Many make little effort here and don't really know what belongs in which bin. But also special waste, such as batteries, incandescent lamps, electrical appliances, etc. must be disposed of properly.

Tap water is preferable, possibly with homemade juices. Otherwise, use returnable glass bottles with drinks from the region. Plastic bottles are problematic, drinks cans are very bad, and Tetra Paks are not easy to recycle.

A lot of things are actually thrown away, even though others could still use them. It is more convenient for us not to repair them than to have a stall at the flea market or to have to send them off for little money. But the good feeling of doing the right thing is motivating.