The world is facing a climate crisis, spurred on by record-breaking levels of atmospheric CO2 generated by the burning of fossil fuels and the destruction of natural ecosystems.
But what if one of the best weapons in our fight against global carbon emissions lies right beneath our feet? That’s the claim of a new generation of biotech firms, who say they can turn the world’s soil into a vast carbon sink, absorbing up to a quarter of annual emissions.
One such company, Soil Carbon Co., based in Australia’s New South Wales, claims that by tailoring communities of microbes that live within farm soil, humans can potentially turn back the clock on human emissions while producing better crops.
“We develop microbiological seed treatments comprised of microbial fungi and bacteria designed to provide plant benefits,” explains Guy Hudson, Soil Carbon Co. CEO. “As that plant grows it exudes sugars into the soil that are converted into stable soil carbon by the fungi.”
Once added to fields by farmers, Hudson says this solution enables the soil to quickly build significant quantities of stable carbon, stored in tiny balls of soil called microaggregates, preventing the carbon from being released back to the atmosphere.
How effective is it this method?
“Results from our studies show a 7-17% soil carbon increase over a season. If you extrapolate out to the 1.8 billion hectares that we crop each year, you would be looking at about 8 gigatons of CO2 equivalent being drawn down,” Hudson claims. Going by IEA stats for 2019, that would equate to just under 25% of the 33 gigatons of CO2 emitted globally that year.
That sounds pretty incredible. But how realistic are such claims?
As any gardener knows, introducing organic matter into the soil using compost improves soil quality, increasing the retention of water and nutrients and resulting in more productive, healthier plants. But in the face of climate crisis, the potential of soil organic matter to store carbon has begun to attract widespread interest.
As the United Nations Framework Convention on Climate Change has repeatedly stipulated, the number one climate action priority must be for nations to reduce emissions at their source. But in conjunction with such efforts, carbon removal processes address the emissions that have already been released: tree planting drives are perhaps the best known of such initiatives, while a raft of chemical processes for capturing carbon are in development, along with numerous other techniques such as the potential of ocean fertilization to capture CO2.
Lofty claims have been made for these methods, too: one study claimed that planting billions of trees could store “an equivalent of 25% of the current atmospheric carbon pool.” But some scientists questioned the practicality of the scale of such a project, saying that, among other difficulties, it could take thousands of years