MEDELLIN, Colombia - Scientists warned Monday that land degradation imperils the health and well-being of billions of people, threatening food and water supplies while fuelling conflict, mass migration and disease spread.
But all is not lost, said the mammoth report by the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES).
Humanity can still turn the tide of destruction, but governments, the private sector, international bodies, and individuals all have a role to play.
The benefits of restoring decayed land are about ten times the cost, the report said.
Measures envisaged by the IPBES report included reflooding drained wetlands, replacing lost trees, and halting pollution at its source -- whether from mines, agriculture, or factories.
In urban areas, it moots the replanting of native species, developing parks, rehabilitating soil sealed under asphalt, treating and reusing wastewater, and restoring river channels.
As the main usurper of natural land, the farming sector must take the lead.
Even simple changes can make a big difference, said Bob Scholes of the University of the Witwatersrand in South Africa, a co-author of the first comprehensive assessment of land health.
Ploughing, for example, leaves the soil vulnerable to erosion and releases carbon locked up in it as planet-warming carbon dioxide.
"How frequently you plough, and for instance, whether you plough straight up and down the hill slope or on the contour makes a huge difference to how much soil you lose," Scholes told AFP.
For IPBES chairman Robert Watson, part of the answer lies in "precision agriculture."
"We have to learn how to appropriately use fertilizers, pesticides and water ... give the crops exactly what they need" and no more.
The IPBES report advocates a dramatic shift in consumer mentality.
Most consumers live far from the ecosystems that produce their food, resulting in "a growing lack of awareness and understanding of the implication" of their purchasing choices, it said.
To correct this, merchants must know where products come from and under what conditions they were produced, and inform consumers accordingly.
"Labelling of food products is very important," Luca Montanarella of the European Commission's Joint Research Centre, another report author, told AFP.
"If you know from the label on your food product that it's coming from a certain area (where) that production system is having a very large impact on the land, a very negative one, well you might choose to buy something else."
This might mean, of course, that the product costs more.
"So it means that you must make choices as a consumer to what is best not only for you but for the planet," said Montanarella.
The IPBES recommends replacing "perverse incentives" that promote land degradation, with positive ones that reward sustainable land management.
One example is subsidised fertilizers.
"If it costs the farmer very little to oversupply of course he'll oversupply," said Scholes. This leads to more runoff into rivers.
Agricultural subsidies, too, lead farmers to overproduce at the expense of Nature, said the team.
The report says governments must take Nature into account in policies across sectors -- not only agriculture and the environment, but also the economy, energy, and infrastructure.
The issue must also be taken up in the global debate on human development and climate change.
"Land degradation, biodiversity loss, and climate change are three different faces of the same central challenge: the increasingly dangerous impacts of our choices on the health of our natural environment," said Watson.
The IPBES, which alerted last week that biodiversity was declining in all world regions, warns that on current trends, the world will fail to meet the 2020 "Aichi Biodiversity Targets" on halting species loss.
Also threatened are the UN's 2030 Sustainable Development Goals, with targets for food and water security, and better human health.
Land degradation furthermore imperils the Paris Agreement on limiting climate change, the report warned.
As land deteriorates, it releases planet-warming carbon into the atmosphere, while forest destruction causes the loss of CO2-absorbing trees.
The next meeting of the IPBES will take place in France in 2019, the same year that the country -- birthplace of the global climate agreement -- will host the G7 club of rich countries.
At that meeting, the IPBES will follow up its regional species reports with a global one that it hopes will spur and consolidate global action.