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By Roger Highfield on

Boosting Soil Health To Curb Climate Change

A new agricultural revolution could be the best way to avert the climate crisis, according to a report out this month. Science Director, Roger Highfield, talks to one of the authors.

Restoring biodiversity in soils, particularly in grasslands, can dramatically increase their capacity to capture and store carbon, reducing the risk of harmful climate change while enhancing biodiversity and providing the burgeoning world population with a more secure food supply.

The potential of regenerative agriculture is highlighted by a report that came out as the UN’s Intergovernmental Panel on Climate Change (IPCC) issued a stark warning that computer models suggest that global carbon emissions now need to decline rapidly for the world to have a 50-50 chance of limiting warming to 1.5 deg C.

‘Transforming agriculture is the planet’s greatest untapped treasure for coping with the climate crisis,’ according to Prof. Thomas Elmqvist of Stockholm University, one of the lead authors of the new report by Europe’s National Academies of Sciences, such as the UK’s Royal Society, entitled Regenerative Agriculture in Europe.

Underlining the IPCC’s message, the report said restoration of ecosystems on an unprecedented scale offers ‘large untapped potential for increasing carbon storage and is increasingly highlighted as one of the most important strategies to keep temperature rise below 2 °C.’

By one estimate, restoring 15% of lands in priority areas could sequester 299 gigatons of CO2 – 30% of the total carbon dioxide increase in the atmosphere since the Industrial Revolution – and at the same time contribute to reduce the alarming rate of extinction of species.

Prof Elmqvist added: ‘There are of course limits and constraints on how much carbon we could capture and store in agricultural land but there is untapped potential below ground – notably in the next two or three decades, before it saturates – because we’ve focused so much on forests to date.’

The report is significant because it is the first by the academies to highlight the potential of the recent and promising concept of regenerative agriculture which is, as it emphasises is ‘from a scientific point of view largely untested’.

Although regenerative agriculture has no agreed definition, the report focuses on what it says are its two key ingredients: restoration, particularly of soil health, including increasing the capacity of soils to capture and store carbon to mitigate climate change; and the reversal of biodiversity loss.

Both offer an antidote to large-scale conventional agriculture, which has huge and deleterious impact on soil through erosion, the loss of flora and fauna and thereby nutrients in soils.

Regenerative agriculture is also seen as a broader and less prescriptive term than, say, organic farming and does not exclude the use of modern plant and animal breeding technology, tilling, use of mineral fertiliser or pesticides.

Instead, it aims for a limited, more targeted use of, say, pesticides and would, for example, not rule out one major opportunity highlighted in the report, nutrient recovery from municipal wastes. ‘You set the goal of enhancing biodiversity, increased carbon capture and maintaining agriculture productivity and then you pick the tools you need to achieve that,’ said Prof Elmqvist.

The main issue facing regenerative agriculture is scale, says the report. ‘There seems to be a belief that regenerative agriculture can only be applied at small scale’, explains Prof Elmqvist. ‘We need to get industrial farmers on board and take a landscape perspective to reach the goals. We have maybe a decade for a massive transformation.’

Many of the practices analysed by the report show synergies between carbon capture and storage, and enhancing biodiversity (although sometimes with only modest effects), while not having clear large negative effects on food production, especially in the long term.

These practices, which should be supported, include increased diversification within and among crops, introduction of permanent and perennial crops, expanded agroforestry and intercropping, keeping green plant cover on all farm fields during all seasons, and reduced tillage.

Some go as far as to argue that, at its simplest, the most important practice for carbon capture and storage in the agricultural landscape is simply to keep the land green, that is, covered by plants during all seasons.

Painting of Jethro Tull demonstrating his seed drill
Painting of Jethro Tull demonstrating his seed drill

Agriculture is the main driver of global deforestation and other changes in land use, and food systems account for more than a third of global greenhouse gas emissions, according to the report.

In European agriculture, emissions of CO2 come mainly from land conversion and use of organic soils (peat) for farming, while other greenhouse gases such as nitrous oxide and methane are emitted mostly by soils, fertilisers and livestock.

These practices continue even though agriculture is vulnerable to the effects of climate change, such as shifts in temperature and rainfall. There is evidence that climate change is also killing off soil organisms such as fungi and microorganisms critical for some of Earth’s ecosystems.

The effects on food production could be stark. A drop in crop yields of between 15 and 30 per cent across much of the UK is predicted by 2080s, relative to 1961–1990 (in high carbon emission scenarios).

More and more farmers, notably the smallholders that produce about a third of the world’s food, are struggling with blighted harvests and livestock losses while trying to adapt to increasingly irregular and extreme weather caused by a changing climate. ‘We are literally sawing the branch that we are sitting on,’ commented Orsolya Valkó of Hungary’s Institute of Ecology and Botany.

However, Orsolya Valkó adds that we are also ‘standing on the largest and most potent carbon capture storage of the planet. Many field tests show how high soil’s storage performance is. If we want not only to preserve biodiversity, expand food production and at the same time fight climate change, there is no alternative to regenerative agriculture.’

The Science Museum’s exhibition, Our Future Planet, focuses on natural and technological ways of removing carbon dioxide, the main greenhouse gas that is driving the rise in global temperature and climate change, both from industrial emissions and from the atmosphere.