As the ready supply of healthy and productive land dries up and the population grows, competition is intensifying for land within countries and globally. Heavy tilling, multiple harvests and abundant use of agrochemicals have increased yields at the expense of long-term sustainability. Over time, however, this diminishes fertility and can lead to abandonment of land and ultimately desertification.
A third of the planet’s land is severely degraded and fertile soil is being lost at the rate of 24bn tonnes a year, according to The Global Land Outlook (Convention to Combat Desertification, 2017). The most comprehensive study of its type, it maps the interlinked impacts of urbanisation, climate change, erosion and forest loss. But the biggest factor is the expansion of industrial farming. "Industrial agriculture is good at feeding populations but it is not sustainable. It’s like an extractive industry". In the past 20 years, agricultural production has increased threefold and the amount of irrigated land has doubled. But, decreasing productivity can be observed on 20% of the world’s cropland, 16% of forest land, 19% of grassland, and 27% of rangeland.
According to the UN Food and Agriculture Organisation, at current rates of soil loss, driven largely by poor farming practice, we have just 60 years of harvests left.
The loss of arable land to urban encroachment and soil erosion means that Bangladesh and Egypt will soon be the only two populous nations with less arable land per capita than China.