What once began as a marketing campaign by the oil company BP is now an important indicator of sustainability: the ecological footprint. Instead of shifting responsibility for climate change onto private individuals alone, it is now companies that are concerned with the consequences of their business activities on the environment. In addition to the carbon footprint for the entire company, more and more manufacturers are also showing one for their products. On the one hand, many consumers want to know what influence their consumption behavior has on climate change. On the other hand, it can be a decisive advantage for suppliers in the competition for customers if they can show evidence of their commitment to greater sustainability. This is already expected of some products anyway: last year, for example, the European Commission adopted a regulation that will in future require mandatory information on the carbon footprint of batteries. A digital product passport is also to be introduced in the EU. The Green Claims Directive also provides a directive according to which companies that advertise sustainability claims must support their claims with evidence and external verification.