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Relocating farmland could turn back clock 20 years on carbon emissions
The reimagined world map of agriculture produced by researchers at the University of Cambridge/ UKingdom includes large new farming areas for many major crops around the cornbelt in the mid-western USA and below the Sahara desert. Huge areas of farmland in Europe and India would be restored to natural habitat.
The redesign – assuming high-input, mechanised farming – would cut the carbon impact of global croplands by 71 per cent by allowing land to revert to its natural, forested state. This is the equivalent of capturing 20 years’ worth of our current net CO2 emissions.
In this optimised scenario, the impact of crop production on the world’s biodiversity would be reduced by 87 per cent, the scientists show in the study. This would drastically reduce the extinction risk for many species, for which agriculture is a major threat. The researchers say that croplands would quickly revert back to their natural state, often recovering their original carbon stocks and biodiversity within a few decades.
The redesign would eliminate the need for irrigation altogether, by growing crops in places where rainfall provides all the water they need to grow. Agriculture is currently responsible for around 70 per cent of global freshwater use.
The researchers used global maps of the current growing areas of 25 major crops, including wheat, barley and soybean, which together account for over three quarters of croplands world-wide. They developed a mathematical model to look at all possible ways to distribute this cropland across the globe, while maintaining overall production levels for each crop. This allowed them to identify the option with the lowest environmental impact.
The study was published in March in the journal Nature Communication Earth & Environment.
“In many places, cropland has replaced natural habitat that contained a lot of carbon and biodiversity – and crops don’t even grow very well there. If we let these places regenerate, and moved production to better suited areas, we would see environmental benefits very quickly,” said Dr Robert Beyer, formerly a researcher in the University of Cambridge’s Department of Zoology, and first author of the study. Beyer is now based at the Potsdam Institute for Climate Impact Research (PIK), Germany.
While a complete global relocation of cropland is clearly not a scenario that could currently be put into practice, the scientists say their models highlight places where croplands are currently very unproductive, but have potential to be hotspots for biodiversity and carbon storage.
Taking a pared-back approach and only redistributing croplands within national borders, rather than globally, would still result in significant benefits: global carbon impact would be reduced by 59 per cent, and biodiversity impact would be 77 per cent lower than at present.
A third, even more realistic option of only relocating the worst-offending 25 per cent of croplands nationally would result in half of the benefits of optimally moving all croplands.
The study finds that the optimal distribution of croplands will change very little until the end of the century, irrespective of the specific ways in which the climate may change.
Cropland must be relocated in a way acceptable to the people it affects
In their study, the researchers cite examples of set-aside schemes that give farmers financial incentives to retire part of their land for environmental benefit. Financial incentives can also encourage people to farm in better suited locations.
The model generated alternative global distribution maps depending on the way the land is farmed – ranging from advanced, fully mechanised production with high-yielding crop varieties and optimum fertiliser and pesticide application through to traditional subsistence-based organic farming. Even redistribution of less intensive farming practices to optimal locations would substantially reduce their carbon and biodiversity impacts.
While other studies show that if we moved towards more plant-based diets we could significantly reduce the environmental impacts of agriculture, the researchers say that in reality diets aren’t changing quickly. Their model assumed that diets will not change, and focused on producing the same food as today, but in an optimal way.
Many of the world's croplands are located in areas where they have a huge environmental footprint. These locations were chosen for historical reasons, such as their proximity to human settlements, but the researchers say it is now time to grow food in a more optimal way.
(University of Cambridge/wi)
Beyer, RM et al: ‘Relocating croplands could drastically reduce the environmental impacts of global food production.’ Nature Communications Earth & Environment, March 2022. DOI: 10.1038/s43247-022-0036