Some 500 years after Leonardo da Vinci declared that more was known about celestial bodies than about the soil underfoot, the United Nations has proclaimed 2015 the International Year of Soils. This offers a unique opportunity to address the crisis in soil sustainability (see www.fao.org/soils-2015).

Among the factors undermining soil quality are intensive farming, industrial activity and increasing urbanization. Soil contamination is threatening food production, water potability and ecosystem services, notably in large parts of China. Safeguarding soils is therefore crucial to the UN Post-2015 Development Agenda and the Sustainable Development Goals (go.nature.com/s7jcik).

Initiatives that are already under way for the sustainable management of complex soil systems include the Intergovernmental Technical Panel on Soils, the Global Soil Biodiversity Initiative, the Global Network of Critical Zone Observatories, and the International Soil Modeling Consortium.