Logs that were illegally cut from Amazon rainforest are transported on a barge on the Tapajos river, a tributary of the Amazon, near the city of Santarem, Para state, Brazil on April 18, 2013. (FILE)   | Photo Credit: REUTERS

Land degradation will unleash a mass migration of at least 50 million people by 2050 — as many as 700 million unless humans stop depleting the life-giving resource, dozens of scientists warned on Monday.

Already, land decay caused by unsustainable farming, mining, pollution, and city expansion is undermining the well-being of some 3.2 billion people — 40% of the global population, they said in the first comprehensive assessment of land health.

The condition of land is “critical,” said the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES).

“We’ve converted large amounts of our forests, we’ve converted large amounts of our grasslands, we’ve lost 87% of our wetlands... we’ve really changed our land surface in the last several hundred years,” IPBES chairman Robert Watson said of the findings.

“The message is: land degradation, loss of productivity of those soils and those vegetations will force people to move. It will be no longer viable to live on those lands,” he said.

“Between now and 2050, we estimate the number could be 50 (million) to some 700 million people.”

The main drivers of land degradation, said the report, were “high-consumption lifestyles” in rich countries, and rising demand for products in developing ones.

The problem of land decay threatens food security for all Earth’s citizens, as well as access to clean water and breathable air regulated by the soil and the plants that grow on it.

Yet less than a quarter of land has managed to escape “substantial impacts” of human activity — primarily because it is found in inhospitable parts of the world. And even this small repository is projected to shrink to less than 10% in just 30 years’ time.

“Tropical rainforests historically have had low human populations because it’s hard to get in there — we are now building roads into them,” said Bob Scholes, a co-author of the paper.

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