Geoengineering has been back in the news recently after the US National Research Council endorsed a proposal to envelop the planet in a layer of sulphate aerosols to reduce solar radiation and cool the atmosphere.
The proposal has been widely criticised for possible unintended consequences, such as ozone depletion, ocean acidification and reduced rainfall in the tropics. Perhaps even more troubling, geoengineering is a technological fix that leaves the economic and industrial system causing climate change untouched.
The mindset behind geoengineering stands in sharp contrast to an emerging ecological, systems approach taking shape in the form of regenerative agriculture. More than a mere alternative strategy, regenerative agriculture represents a fundamental shift in our culture’s relationship to nature.
Regenerative agriculture comprises an array of techniques that rebuild soil and, in the process, sequester carbon. Typically, it uses cover crops and perennials so that bare soil is never exposed, and grazes animals in ways that mimic animals in nature. It also offers ecological benefits far beyond carbon storage: it stops soil erosion, remineralises soil, protects the purity of groundwater and reduces damaging pesticide and fertiliser runoff.
But these methods are slow, expensive and impractical in feeding a growing population, right?
Wrong. While comprehensive statistics are hard to come by, yields from regenerative methods often exceed conventional yields (see here and here for scientific research, and here and here for anecdotal examples). Likewise, since these methods build soil, crowd out weeds and retain moisture, fertiliser and herbicide inputs can be reduced or eliminated entirely, resulting in higher profits for farmers. No-till methods can sequester as much as a ton of carbon per acre annually (2.5 tons/hectare). In the US alone, that could amount to nearly a quarter of current emissions.
Estimates of the total potential impact vary. Rattan Lal of Ohio State University argues that desertified and otherwise degraded soils could sequester up to 3bn tons of carbon per year (equal to 11bn tons of CO2, or nearly one third of current emissions). Other experts foresee even greater potential. According to research at the Rodale Institute, if instituted universally, organic regenerative techniques practiced on cultivated land could offset over 40% of global emissions, while practicing them on pasture land could offset 71%.
That adds up to land-based CO2 reduction of over 100% of current emissions – and that doesn’t even include reforestation and afforestation, which could offset another 10-15%, according to the Intergovernmental Panel on Climate Change. Of course, none of this is license to perpetuate a fossil fuel infrastructure, since there is an eventual limit to the amount of carbon that soil and biomass can store.