The Soil Solution to Climate Change
December 21, 2015
While the world focused on a deal to reduce emissions, another international initiative was quietly signed at the Paris climate conference, highlighting a critical but little known climate solution: soil.
In the first few days of COP21, in a standing-room-only crowd of 300+ delegates, French Minister of Agriculture Stéphane Le Foll championed the signing of a visionary initiative to increase the organic carbon level of agricultural soils by 0.4 percent each year.
According to the signatories from more than 25 countries—including France, Australia, Mexico, Germany and Japan—and hundreds of food, agriculture and research organizations, regenerative agricultural practices that store excess carbon in the soil have the potential to cool the planet and feed the world.
The 4/1000 Initiative: Soils for Food Security and Climate, consists of a voluntary action plan under the Lima-Paris Action Agenda (LPAA), backed up by an ambitious research program. It aims to show that food security and combating climate change are complementary. It also positions our farmers as the pioneering climate heroes of our generation.
“The conclusion is simple,” said Le Foll in a statement at COP21. “If we can store the equivalent of 4 per 1000 (tons of carbon) in farmland soils, we are capable of storing all man-made emissions on the planet today.”
“This is the most exciting news to come out of COP21,” said Andre Leu, president of IFOAM—Organics International. “By launching this initiative, the French government has validated the work of scientists, farmers and ranchers who have demonstrated the power of organic regenerative agriculture to restore the soil’s natural ability to draw down and sequester carbon.”
The world has lost a third of its arable land due to erosion or pollution in the past 40 years, with potentially disastrous consequences as global demand for food soars, scientists have warned.
New research has calculated that nearly 33 percent of the world’s adequate or high-quality food-producing land has been lost at a rate that far outstrips the pace of natural processes to replace diminished soil.
The University of Sheffield’s Grantham Centre for Sustainable Futures, which undertook the study by analysing various pieces of research published over the past decade, said the loss was “catastrophic” and the trend close to being irretrievable without major changes to agricultural practices.
The continual ploughing of fields, combined with heavy use of fertilizers, has degraded soils across the world, the research found, with erosion occurring at a pace of up to 100 times greater than the rate of soil formation. It takes around 500 years for just 2.5cm of topsoil to be created amid unimpeded ecological changes.
“You think of the dust bowl of the 1930s in North America and then you realize we are moving towards that situation if we don’t do something,” said Duncan Cameron, professor of plant and soil biology at the University of Sheffield.
“We are increasing the rate of loss and we are reducing soils to their bare mineral components,” he said. “We are creating soils that aren’t fit for anything except for holding a plant up. The soils are silting up river systems – if you look at the huge brown stain in the ocean where the Amazon deposits soil, you realise how much we are accelerating that process.
“We aren’t quite at the tipping point yet, but we need to do something about it. We are up against it if we are to reverse this decline.”
The erosion of soil has largely occurred due to the loss of structure by continual disturbance for crop planting and harvesting. If soil is repeatedly turned over, it is exposed to oxygen and its carbon is released into the atmosphere, causing it to fail to bind as effectively. This loss of integrity impacts soil’s ability to store water, which neutralizes its role as a buffer to floods and a fruitful base for plants.
Degraded soils are also vulnerable to being washed away by weather events fueled by global warming. Deforestation, which removes trees that help knit landscapes together, is also detrimental to soil health.
The steep decline in soil has occurred at a time when the world’s demand for food is rapidly increasing. It’s estimated the world will need to grow 50 percent more food by 2050 to feed an anticipated population of 9 billion people. According to the UN’s Food and Agriculture Organisation, the increase in food production will be most needed in developing countries.
The academics behind the University of Sheffield study propose a number of remedies to soil loss, including recycling nutrients from sewerage, using biotechnology to wean plants off their dependence upon fertilizers, and rotating crops with livestock areas to relieve pressure on arable land.
Around 30 percent of the world’s ice-free surfaces are used to keep chicken, cattle, pigs and other livestock, rather than to grow crops.