The water used to produce food available in urban areas generally doesn’t make it into city sustainability estimates, which only take into account direct water use and parameters such as waste collection and energy efficiency of buildings. This can distort estimates, as, for example, in the Mediterranean, water consumed elsewhere in the cultivation and the processing of the food delivered to consumers in cities surpasses the direct water use per capita at least 20 times, according to a JRC-led report. Certain healthier diets could however not only benefit consumers but also reduce the water footprint by up to 53%.
The findings come from a study carried out in the framework of the forthcoming Pan-European Atlas of Urban Water Management, prepared through the EU-funded project BlueSCities-Making water and waste smart. The study quantified the water footprint (WF) related to food consumption in 13 Mediterranean cities. WFs estimate the water required to produce the food originating from outside the city limits and destined for consumption in the cities. The various WFs range from 3277 liters per person per day (l/cap/d) to 5789 l/cap/d, depending on the city. These are 20 to 30 times larger than direct domestic water use (for drinking, cooking, personal hygiene, etc.), which amounts to 125-200 l/cap/d in the cities examined.
Together with nutrition specialists from Spain, Greece, Israel and Turkey, the JRC evaluated the current dietary habits in the selected cities compared to the traditional Mediterranean diet. Many researchers identify the Mediterranean diet as beneficial for human health and a model for a sustainable food system.
As previous research also showed, diet preference in Mediterranean cities is gradually moving away from the traditional Mediterranean diet to a more Western-style diet, and now includes increasing amounts of fat, sugar and meat. These foodstuffs are very water intensive to produce. Therefore, a shift to a diet containing less animal products and more vegetables and fruit, besides offering health benefits also substantially lowers cities’ water footprint. Depending on the city, a healthy diet containing meat reduces its water footprint by 19% to 43%; a pesco-vegetarian diet by 28% to 52% and a vegetarian diet by 30% to 53%.
In other words, diet choice can save water and greatly improve the sustainability of Mediterranean cities, which – due to a warmer climate – already consume more water than cities further north. The authors of the study recommend that indicators on the use of external resources need to be included in international sustainability rankings for cities in order to communicate the full picture of resource consumption to citizens, stakeholders and policy makers.