Marginal improvements to agricultural soils around the world would store enough carbon to keep the world within 1.5C of global heating, new research suggests.
Farming techniques that improve long-term fertility and yields can also help to store more carbon in soils but are often ignored in favour of intensive techniques using large amounts of artificial fertiliser, much of it wasted, that can increase greenhouse gas emissions.
Using better farming techniques to store 1% more carbon in about half of the world’s agricultural soils would be enough to absorb about 31 gigatonnes of carbon dioxide a year, according to new data. That amount is not far off the 32 gigatonnes gap between current planned emissions reduction globally per year and the amount of carbon that must be cut by 2030 to stay within 1.5C.
The estimates were carried out by Jacqueline McGlade, the former chief scientist at the UN environment programme and former executive director of the European Environment Agency. She found that storing more carbon in the top 30cm of agricultural soils would be feasible in many regions where soils are currently degraded.
McGlade now leads a commercial organisation that sells soil data to farmers. Downforce Technologies uses publicly available global data, satellite images and lidar to assess in detail how much carbon is stored in soils, which can now be done down to the level of individual fields.
“Outside the farming sector, people do not understand how important soils are to the climate,” said McGlade. “Changing farming could make soils carbon negative, making them absorb carbon, and reducing the cost of farming.”
She said farmers could face a short-term cost while they changed their methods, away from the overuse of artificial fertiliser, but after a transition period of two to three years their yields would improve and their soils would be much healthier.
She estimated it would cost about $1m (£790,000) to restore 40,000 hectares (99,000 acres) of what is currently badly degraded farmland in Kenya, an area that is home to about 300,000 people.
Downforce data could also allow farmers to sell carbon credits based on how much additional carbon dioxide their fields are absorbing. Soil has long been known to be one of Earth’s biggest stores of carbon, but until now it has not been possible to examine in detail how much carbon soils in particular areas are locking up and how much they are emitting. About 40% of the world’s farmland is now degraded, according to UN estimates.
Carbon dioxide removal, the name given to a suite of technologies and techniques that increase the uptake of carbon dioxide from the air and sequester the carbon in some form, is an increasing area of interest, as the world slips closer to the critical threshold of 1.5C of global heating above pre-industrial levels.
Arable farmers could sequester more carbon within their soils by changing their crop rotation, planting cover crops such as clover, or using direct drilling, which allows crops to be planted without the need for ploughing. Livestock farmers could improve their soils by growing more native grasses.
Hedgerows also help to sequester carbon in the soil, because they have large underground networks of mycorrhizal fungi and microbes that can extend metres into the field. Farmers have spent decades removing hedgerows to make intensive farming easier, but restoring them, and maintaining existing hedgerows, would improve biodiversity, reduce the erosion of topsoil, and help to stop harmful agricultural runoff, which is a key polluter of rivers.
Farming has changed since the 1920s. Tilling has been out of style for decades now.
How your grandma did her garden is not good for the soil…sure plant one, but first put aside your ignorance about how modern farms work and do it right. (Finding good information us hard, garden magazines last I.checked were full of misinformation that isn’t backed by modern research)
Have any sites you would recommend for modernized home gardens?
Iowa state university has some small farmer info that is useful, but they are specific to the iowa climate (I live in iowa so this is good for me), but they only publish a small amount, most of what they do is focuses on large farms (in part because that is who listens). I suspect your area also has a research university with an ag focus.
I have had some success reading between the lines of their large farm focused things as well. Whoever it doesn’t make sense for a home garden to grow corn, corn likes large fields and doesn’t do as well in small gardens. I think wheat is similar (nobody grows wheat in iowa so I don’t know much about it)
It’s perfectly fine to grow crops in a home garden if done right. It’s a lot of work if you want to eat bread, cakes, brew beer, and so on, all at the same time obviously. Monoculture is never the right thing to do in terms of sustainability. Just watch nature do it’s work. You won’t find monoculture in any sustainable ecosystem.
No, tilling is definitely still the norm, and soil is still degrading with decreasing nutritional value of crops each year.
I cannot tell where you live from your profile. Different parts of the world have different situations, at least where I live (Iowa - major farming state) plowing is not common. There are other types of tilling, but they don’t degrade the soil as backed by real research.
so it’s changed from we havent been tilling for decades, to it’s a different kind of tilling. It’s tilling, it’s tearing up the root system and exposing the microbiome to dry air and sunlight. You’ve seen the dirt, it’s dead clay on those fields.
But here is the thing, it doesn’t tear up the root system. It just loosens the soil. Roots remain on place. Modern ag is a.wonder backed by real science. It is building up the soil (about 1mm per year, sounds slow but is fast on a geological timeline)
Modern ag is chemical fertilizer runoff and decreasing vitamins and minerals in produce.