Water use for food production today largely occurs on the expense of ecosystems. about 40 percent of the water used for irrigation are unsustainable withdrawals that violate so-called environmental flows of rivers, a new study shows for the first time. If these volumes were to be re-allocated to the ecosystems, crop yields would dro by at least 10% on half of all irrigated land, especially in Central and South Asia. 

This points to a tradeoff between water and food UN Sustainable Development Goals. However, improvement of irrigation practices can sustainably compensate for such losses at global scale. More integrated strategies, including rainwater management, could even achieve a 10 percent net gain in production.

“Seemingly conflicting elements of the Sustainable Development Goals (SDGs) can be reconciled if addressed properly,” says Jonas Jägermeyr from the Potsdam Institute for Climate Impact Research, lead author of a team of scientists from institutions including the International Institute for Advanced Systems Analysis and Wageningen University. “Agricultural production and water management are key examples since food production will likely double in the future while the water cycle will regionally be disturbed by climate change.” The study in Nature Communications provides new quantitative evidence that negative environmental effects can be avoided while maintaining food production at global level. Much of this potential can be realized through traditional and affordable farmers’ practices accessible for smallholders.

Just recently, this topic has been emphasized at the highest political level by the leaders of the world’s greatest economies, the G20. Their Hamburg Declaration states: “In order to achieve food security, we are committed to increasing agricultural productivity and resilience in a sustainable manner while aiming to protect, manage and use efficiently water and water-related ecosystems.” The SDGs are also the basis for Germany’s sustainability strategy.

This study details how such visions could start to fall into place without relying on future technology fixes. “This requires an improvement of irrigation systems, together with better management of rainwater,” says Hester Biemans of Wageningen Environmental Research (Alterra). “Water-saving measures are crucial for achieving the objectives. By implementing well-known and affordable farming techniques that are already available to small farmers, agricultural production can be increased by more than 20% in many regions."