Methane producer cow and the CO2 equivalents
Steak, schnitzel, gyros and salami – are these foods climate killers? Scientists answer the question in the affirmative. A reduction in meat consumption and the associated reduction in livestock could slow down global warming.
Ruminants burp and release methane
Agriculture accounts for about 13% of annual greenhouse gas emissions. The sources are diverse (Fig. 2). Ruminants such as cattle, sheep and goats are a significant source of greenhouse gases, in whose stomachs large quantities of methane (CH4) are released by bacterial symbionts (Fig. 3, material 3). The methane produced in the "beef fermentation reactor" enters the atmosphere through "burps" and through the faeces.
What is the CO2 equivalent and how does it relate to methane?
Due to its molecular structure, methane can absorb significantly more radiant energy than carbon dioxide (CO2). In order to be able to compare the various greenhouse gases with each other, a uniform assessment basis was established: the CO2 equivalent (CO2e; "E" stands for "equivalent"). One kilo of methane (21 CO2e) contributes 21 times more to the greenhouse effect than one kilo of CO2.
This is how much CO2e a cow causes
How much methane a cattle releases depends, among other things, on its diet. The average is 300 g CH4/day/beef. According to the Bavarian Farmers' Association, this is little, as an elephant emits as much as 2,400 g CH4/day. The environmental protection organization WWF (World Wildlife Fund) sees it quite differently. It compares the 300 g CH4/day/cattle with the CO2 emissions of a car (130 g CO2/km), which are perceived by the public as particularly harmful to the climate. Taking into account the 21-fold greater climate impact of methane, the WWF makes the following calculation: 300 g CH4/day/cattle corresponds to 6,900 CO2/day/cattle. If this value is divided by the CO2 emissions of a car per kilometre, the greenhouse gas emissions of a cow correspond to a car mileage of over 50 km/day or just under 20,000 km/year.
Belgium introduces Veggieday
These figures speak for reducing meat consumption for reasons of climate protection. This was also the conclusion reached by representatives of the Belgian city of Ghent, who introduced a weekly "Veggiedag" ("Vegetable Day") in all public canteens and school canteens in 2009. In the meantime, there are similar initiatives in German cities, since 2010, for example in Bremen: In schools, canteens and daycare centers, meat is to be avoided every Thursday (www.veggiday.de).
Since 2009, Ghent, Belgium's third-largest city, has had a vegetarian day, the "Veggiedag". Municipal canteens, school kitchens and university canteens cook only vegetarian food on Thursdays. Many restaurants also put meatless dishes on their menus. With this campaign, the people of Ghent want to make a contribution to climate protection and reduce CO2 emissions.
The trigger was the Indian climate expert Pachauri, who gave a lecture in Ghent in 2008 on the topic of meat consumption and climate, motto: "Less meat, less heat". According to many scientists, methane emissions, which cattle in particular, but also other ruminants, produce during digestion, are responsible for almost a fifth of global greenhouse gas emissions. The people of Ghent thought about it and came to the conclusion: For the sake of the climate, "Donderdag = Veggiedag" will be "Donderdag = Veggiedag" in the future, Thursday will be vegetable day. The Vegetarian Day reminds us that everyone can make a small contribution to protecting the climate. In addition, giving up meat is good for your health.
Of course, no one is forced to give up meat. Especially for Western Europeans who are used to meat consumption, it is not so easy to have a vegetarian day. But the campaign has been successful: Ghentians now eat twice as many vegetarian dishes as they did before the introduction of Veggiedag. The participating gourmet restaurants prove that the renunciation of meat does not necessarily lead to a renunciation of taste.
In the meantime, Veggiedag has set a precedent: in Belgium, Brazil and Germany, other cities have also introduced a weekly Veggiday.
Teaching Considerations
The topic of "climate change" is omnipresent in the media today. As one of the key topics of the UN Decade of Education for Sustainable Development (ESD), "climate change" is increasingly finding its way into the classroom, e.g. through the treatment of energy use in the domestic sector. It is only recently that food production has been linked to climate change. There is still a great need for information among the pupils here.
Sustainable teaching topics can open up new perspectives
According to the recommendations of the KMK and the German Commission for UNESCO (DUK), sustainability topics in the classroom should, among other things, "enable pupils to relate to their everyday lives and take a global view of the world", "sufficient opportunities for action for the individual and/or the community" and "favourable conditions for self-organised learning and a change of perspective". These requirements are met by the field of needs "nutrition".
Everyday approach to the climate problem
Nutrition is also a good access to the climate change problem for other reasons: Unlike buying a car, for example, purchasing decisions for or against certain foods have to be made almost every day. The students can choose for themselves or at least influence the purchase. The purchase alternatives – e.g. vegetarian food instead of meat, poultry instead of beef – open up alternative behavioural options for them. In addition, the purchase of food is often far less dogmatic than the purchase of other consumer goods and can therefore be discussed more openly. The question of "climate-friendly food" can thus be an opportunity to talk to pupils about the impact of their own consumer behaviour on greenhouse gas emissions.
Not just empty phrases
"Vegetarians eat the food away from my food!" – this jokingly formulated rejection of vegetarianism is often put forward by students as a serious objection to a plant-based diet. The argument of "global food security through meat production" falls into the same category. In fact, livestock consume far more feed than they produce food: about a third of the world's grain harvest is fed to livestock (Rifkin 2001) and 16 g of plant proteins must be used to produce 1 g of animal protein.
Role-playing: Veggieday also at my school?
Following the information phase, a role play offers the pupils the opportunity to look at the problem from different perspectives. They can develop various scenarios, anticipate possible consequences and discuss the values behind the arguments. Continue reading on page 2!