That's nearly five percent of the city's total area, according to the study, which is due to appear in the April issue of the journal Sustainable Cities and Society. "Up to 80 percent of Berlin's vegetable needs could be met locally if all these areas were used for urban gardening," explained co-author Diego Rybski, who works at PIK and the Wuppertal Institute and is a member of the Complexity Science Hub Vienna.

However, the researchers involved concede that the use of the theoretically available areas would entail considerable challenges. For example, investments of more than 750 million euros would be required, and there was also a need for clarification with regard to the required personnel and irrigation. The production costs for the vegetables from Berlin would also be relatively high - depending on the earnings situation, the study assumes two to ten euros per kilogram.

But even "if only a fraction of the theoretically available area were used for growing vegetables in Berlin, that would be an important change in order to avoid emissions from global food transport," explained co-author Prajal Pradhan. "Urban agriculture also reduces urban heat islands and can protect biodiversity," he said. However, this requires sustainable management.