Three-quarters of Earth’s land has become drier since 1990. A new report from scientists convened by the United Nations found that an area as large as India has become arid, and it’s probably permanent.
A transition from humid to dry land is underway that has shrunk the area available to grow food, costing Africa 12% of its GDP and depleting our natural buffer to rising temperatures.
Why is the land drying out so fast? It’s partly because there is more heat trapped in the atmosphere by greenhouse gases emitted from burning fossil fuels. This excess heat has exacerbated evaporation and is drawing more moisture out of soil.
Climate change has also made the weather more volatile. When drought does cede to rain, more of it arrives in bruising downpours that slough the topsoil.
A stable climate would deliver a year’s rain more evenly and gently, nourishing the soil so that it can nurture microbes that hold onto water and release nutrients.
This is the kind of soil that industrial civilization inherited. It’s disappearing.
“Soil is being lost up to 100 times faster than it is formed, and desertification is growing year on year,” says Anna Krzywoszynska, a sustainable food expert at the University of Sheffield.
“The truth is, the modern farming system is based around oil, not soil.”
Fossil fuels have unleashed agriculture from the constraints of local ecology. Once, the nutrients that were taken from the soil in the form of food had to be replaced using organic waste, Krzywoszynska says. Synthetic nitrogen fertilizers, made with fossil energy at great cost to the climate, changed all that.
Next came diesel-powered machinery that brought more wilderness into cultivation. Farm vehicles as heavy as the biggest dinosaurs now churn and compact the soil, making it difficult for earthworms and assorted soil organisms to maintain it.
Tractors and chemicals served humanity for a long time, Krzywoszynska says. But soil is now so degraded that no amount of fossil help can compensate.
“Across the world, soils have been pushed beyond their capacity to recover, and humanity’s ability to feed itself is now in danger.”
Climate change has also made the weather more volatile. When drought does cede to rain, more of it arrives in bruising downpours that slough the topsoil.
A stable climate would deliver a year’s rain more evenly and gently, nourishing the soil so that it can nurture microbes that hold onto water and release nutrients.
This is the kind of soil that industrial civilization inherited. It’s disappearing.
“Soil is being lost up to 100 times faster than it is formed, and desertification is growing year on year,” says Anna Krzywoszynska, a sustainable food expert at the University of Sheffield.
“The truth is, the modern farming system is based around oil, not soil.”
Fossil fuels have unleashed agriculture from the constraints of local ecology. Once, the nutrients that were taken from the soil in the form of food had to be replaced using organic waste, Krzywoszynska says. Synthetic nitrogen fertilizers, made with fossil energy at great cost to the climate, changed all that.
Next came diesel-powered machinery that brought more wilderness into cultivation. Farm vehicles as heavy as the biggest dinosaurs now churn and compact the soil, making it difficult for earthworms and assorted soil organisms to maintain it.
Tractors and chemicals served humanity for a long time, Krzywoszynska says. But soil is now so degraded that no amount of fossil help can compensate.
“Across the world, soils have been pushed beyond their capacity to recover, and humanity’s ability to feed itself is now in danger.”
The primary way that we have been making up for lost food yield is turning more forests into farms. This is accelerating our journey towards a drier, less liveable world because forests, if allowed to thrive, create their own rain.