In a recent study, researchers from the University of Delaware summarized the state of the world’s soil, and it’s not positive. They found that soil quality has reached a low point never before seen. Poor global soil quality is the byproduct of a number of factors, including climate change, soil erosion, nutrient exhaustion, and urbanization.

Soil quality

Most, if not all, of the problem is the result of human activities. Humans developed agriculture about 10,000 years ago, though it is more recent centuries that the largest impact has been made. At present, about 40% of the world’s land area is given over to agriculture, and urbanization is rapidly eating up much of the other land. It will likely get worse as the Earth’s population is projected to hit 11 billion people by 2100.

One of the big problems is erosion. Normally, as soil is eroded away by wind, water, and geology, it is replaced with new soil created through natural processes like decomposition. Unfortunately, in most parts of the world impacted by humans, the rate of erosion is not being matched by the rate at which new soil is being created. In the central United States, considered the “bread basket” of the nation, soil erodes at roughly ten times the rate of new soil production.

Old soil becomes increasingly devoid of the nutrients required for plants to grow. One way to help offset this, historically, has been the use of fertilizers, and fertilizers are increasingly necessary for fields to yield crops. This is reflected in fertilizer prices, which have been rising for years now. What’s worse is that fertilizer production is not sustainable: the largest American deposit of rock phosphate, which provides the nutrient phosphorous required for fertilizer, is only estimated to last another 20 years or so.

It’s possible to import phosphorous, or even fertilizer, but that will make things even more expensive. If things don’t change, arable land stands poised to make a big comeback as a source of geopolitical conflict.