It is always a consideration whether the further use of an older device does not require less energy or water than the production of a new, energy-efficient device. Therefore, the energy requirement along the entire product life cycle (from production to use to disposal) must be considered. Companies need the competence to weigh up the right time for a new purchase of devices, but also the determination to then purchase the most sustainable and not only cheapest devices.

LED 'light bulbs' are now available for really all lamps, even with pleasantly warm light colors. Also, think about the lights outside - are they LED as well?

Standby electricity consumption is often admonished and extrapolated. For example, if a TV consumes 5 watts in standby, that is 120 watt hours (Wh) per day, i.e. about one-eighth of a kilowatt hour, which costs about 35 cents. Schools can easily calculate for themselves what savings potential all their computers, copiers and interactive boards etc. have if they do without standby.

Modern lamps require little electricity, but all in all it is worthwhile not to let them burn unnecessarily, for example when we are not in the room for a long time. Corridors, toilet rooms, basements often have the lights on unnecessarily. In some areas, schools also have the lights on too long or too early.

The compensation of greenhouse gas emissions is very controversial. Someone flies, drives a car or organises a barbecue and donates an amount for the associated greenhouse gas emissions to a service provider who promises projects for greenhouse gas savings / binding (e.g. via forest reforestation). Unfortunately, many providers turn out to be flimsy because they do not achieve the promised effect at all. So only reputable providers should be supported. In addition, the compensation should not be misunderstood as a free pass. It is therefore important to avoid emissions as far as possible and only offset them for the rest (see also the point on donations). It is also conceivable that the school itself will plant a school forest or a meadow orchard. Municipalities usually have to create compensation areas for new development areas. The schools could then plant trees in great campaigns. It is important to note that offsets do not - as some people completely falsely claim - enable the continued use of fossil fuels. It's all about offsetting unavoidable emissions.

Most classrooms are too warm in winter - some walk around in T-shirts instead of wearing thick sweaters or a cardigan. The energy-saving potential is considerable.

Air conditioning systems are also gaining in importance in temperate latitudes. Intelligent construction and ventilation and the use of thermal protection roller blinds can avoid these power guzzlers. In warm regions, a corresponding education of the guests can take place. Often a fan is also useful.

Intelligent ventilation does not mean too late and not too long. It is too late when we get tired when we get tired with stale air, get headaches and the humidity becomes too high. It is too long if the air has already been exchanged and is cool, but we also ventilate the materials (walls, furniture) for even longer. Heat ultimately means that things or air vibrate. If the air is exchanged, but the objects and walls are still vibrating, the fresh air is quickly heated. If the walls also get cold, mold can form on them and we need expensive heating energy to get everything vibrating again. By the way, CO2 measuring devices help to ventilate in good time and not for too long. However, these should not be a useless gadget, but perhaps used for practice one after the other in the rooms and should also be lent out. A nice game is the competition to see how good the sense of the people in the room is to ventilate in time and not too long. Schools in particular have the potential to keep the doors in the entrance area not too wide and not too long.

Unlike the vegan diet, a vegetarian diet can also include milk, cheese or eggs. Vegetarian days are healthy, mean less animal husbandry and thus less consumption of land and water. People in the industrialized world consume more than three times more animal products, which according to the EAT-Lancet Commission would be healthy for us and the planet. We don't have to become vegans or vegetarians right away, but maybe just flexitarians.

Legumes are not only an alternative source of vegetable proter to animal products, but also extremely important for world nutrition. They bind nitrogen from the air in the soil and can achieve just as high yields in organic farming as in industrial agriculture. So we have to cut down fewer forests. In addition, legumes are healthier than cereals. Harari describes in Sapiens how we could probably get much older if we didn't eat so much cereal products. After all, legumes are important for bees and biodiversity. Lupine, for example, also grows in northern Germany and can be used for meat substitutes, yogurt, coffee substitutes, ice cream or even noodles.

Fortunately, tap water has long been a trend. Schools have drinking water dispensers and students have their drinking bottles with them, and managers also bring their drinking bottles to workshops. Many children are not even used to the unhealthy sugar drinks. Tap water is more strictly controlled than bottled beverages and saves a lot of energy and packaging. Schools can set up water dispensers - if necessary, also work with filters, for example to remove chlorine odors.

Food is wasted from the field to the factories and transport routes to the throw away by us, the restaurants and the supermarkets. This ultimately means that more areas are needed for cultivation and thus forests are cut down and biodiversity is endangered with sprays and fertilizers. We can shop more specifically, throw away goods not only because of the best before date, save food in the household (e.g. freeze bananas or make durable spreads and soups from leftover vegetables yourself), save specifically rescued food (e.g. too small or wrinkled goods) and also donate leftover food in many places, e.g. to the food banks. Canteens and kiosks and also events can query the demand in advance and thus prevent food from being thrown away. A dish can also be deliberately offered the next day, which advertises the utilization of the leftovers from the previous day.

For most people, flying is a great experience like experiencing distant places. Flying short-haul routes should rightly lead to 'flight shame' - some countries are planning to ban domestic flights altogether. The problem with flying is, on the one hand, that we cover a lot of kilometers, even if the energy requirement per kilometer and person is not that high. On the other hand, greenhouse gases are transported directly to the heights where they harm us. So we should only use the plane for rare long-distance trips and then stay longer in the places. Unfortunately, flying is even subsidized and is often cheaper than train or car. Nevertheless, school trips should avoid air travel.

What has recently been a successful model in some countries and cities is still a problem in Germany: giving cyclists priority over car traffic. The willingness to ride a bike, even in bad weather, is higher than ever before. E-cargo bikes make it possible to at least do without a second car. A school can do a lot with a bicycle shelter with charging facilities. If teachers or parents are concerned about the theft of e-bikes, schools can also develop ideas for this.

No question - leaving the car behind and taking the bike is a proud feeling and healthy. If you don't want to exhaust yourself (for example on the way to work), you can consider an e-bike. If you have a lot to transport, a cargo bike. Often we can also share a cargo bike with others. And if you shy away from bad weather, you will find great cycling clothing today that completely invalidates the argument. Schools can support their teachers here.

Consistently separating waste, including green waste, glass and paper, is not as self-evident as one might assume. Many make little effort here and don't really know what belongs in which bin. The residual waste bin also costs the school authority a lot of money, while the recycling and green waste bins are free of charge. Schools should set up separation containers in the classrooms, but also in the corridors and the schoolyard. Most of the time, the argument is that the cleaners only have a garbage bag available and no time. That can definitely be solved. The second argument is that the students do not separate properly. Here, for example, weekly 'environmental services' can be held responsible for the separation, which will certainly sooner or later lead to insight among everyone.

Saving paper helps to protect forests - recycling paper also ultimately means more demand for fresh pulp from trees. We don't even need to print out a lot of things, but can save them on devices that we already have. Digital forms should become more and more popular for internal processes but also for dialogue with students. On the one hand. On the other hand, studies currently differ as to whether complete digitization of teaching or its materials leads to better performance.

After unpackaged and for drinks after tap water, the best thing we can do is to buy our food in reusable containers. (By the way, there are also reusable shipping boxes for office supplies, as is the case with some regional delivery services). Also ask whether the containers are transported empty throughout Germany, or whether North German beer flows into the empty bottle of Bavarian beer and vice versa. The next question is what it costs in energy to clean the containers. Composite packaging or easy-to-recycle cans are the better alternative in some studies. In such studies, you have to look closely at what is being compared. Ultimately, it is important to close regional cycles. Next question is whether the containers should be made of glass or plastic - glass is recycled more often, plastic is lighter and means less energy during transport. If schools are supplied, it should definitely be checked what can be transported in returnable containers.

Garbage collection as an event also for the clubs with subsequent meeting, possibly sponsored by the local economy, helps to get nature clean and to raise awareness. Companies can sponsor or participate as a team.

Land sealing is not only a problem in growing civilizations, but also in Germany. We live on too much living space, are still building new roads and driveways and our terraces are also getting bigger and bigger. To deliberately forego space here, to build upwards, water-permeable paving, green roofs (separate point) and, weighing up all the advantages and disadvantages, to expand one's own house upwards in order to enable more people to live on the same sealed area, are valuable steps. By the way, an English lawn is ecologically invaluable compared to a flower or clover meadow or a vegetable garden, for example. Schools can systematically look at which areas do not need to be sealed and can perhaps be provided with flower meadows.

In many places, moors, streams, etc. have been lost with settlement and the intensification of agriculture. Renaturing them often means an enormous gain for biodiversity, climate protection and flood protection. Schools can look at their own land to see if something needs to be renaturalised, or actively and instructively participate in projects as a school class or club or as sponsors.

Insect hotels or just old, higher tree stumps and dead wood on the ground, nesting boxes and, if useful, bat boxes are great ways to maximize biodiversity in your own environment. School classes can also participate here.

At first glance, schools are denied this step - they have to remain politically neutral and can actually only indirectly motivate and tolerate students to participate if they participate in demonstrations and not in class.

Schools can offer sustainability days, flea markets, clothing bazaars, food festivals, repair cafes, etc. for citizens to come together.

Societies must take in refugees - no matter how many there are. A distinction must be made between this and the number of those whom we can also integrate into our society in the long term and, with a view to our economy and retirement provision or demographic change. A municipality should actively lead the way and help refugees, take them in and also invite citizens to help, donate and meet the people. Refugees can then also help to help refugees. Linguistically, English is sometimes the lowest common denominator, which can also be chosen in companies. So far as legal, we should help these people. Schools are usually already doing a lot here - integrating refugee children and offering additional language courses. In detail, there are many other great solutions for group work, sponsorships or even voluntary activities in the afternoon, for example for the integration of the other members of the refugee families.

Bringing people together in the world is more important than ever in times of globalization. Companies can also get involved here beyond the direct economic interest.

Educational trails, information boards, exhibitions, excursions, etc., if necessary also together with schools and nature conservation organizations.

Many schools organize charity runs, charity campaigns (Advent markets) etc. or/and they have partnerships with schools in developing countries. Donations have a double effect - they help the recipients and they reduce the consumption of the givers.

Unfortunately, many devices can no longer be repaired at all, for example if the control unit breaks down from the washing machine and costs more than a new washing machine. And yet there are workshops that also repair mobile phones, washing machines, lawn mowers, etc. - and even if it is as expensive as a new device, it is the good feeling of having done something for a better world again.

This does not mean the skate track or the artificial turf sports field, but motor sports, skiing on artificially snowed slopes, kiting in bird sanctuaries, sailing boats with biocides on the underwater hull, golfing with high water and pesticide use, quad bike rides in nature, parachuting, etc. Of course, these hobbies are fun, which is why it is rewarded if we actively choose the more environmentally friendly alternatives here and thus achieve a change in thinking among others.