According to a large new analysis of over a decade of research, farming should be as high-yield as feasible so that it may be limited to relatively small areas, allowing considerably more land to be left as natural habitats while yet reaching future food targets.
Most species fare better under this “land sparing” method than when farming seeks to share the land with nature because wildlife-friendly agriculture still depletes biodiversity and takes significantly more land to produce the same amount of food.
This is the finding of a study that examined over 2,500 plant, insect, and vertebrate species from five continents individually. Prof Andrew Balmford’s review also implies that “land sparing” sequesters more carbon and, if applied to oceans, may benefit marine life.
“Figuring out how to feed, clothe and power 11 billion people without causing mass species extinction and wrecking the climate is this century’s greatest challenge,” he said. “Preserving diverse life while meeting humanity’s needs will mean enormous trade-offs, but the evidence is starting to point in one direction.”
In a paper published today in the Journal of Zoology, Balmford lays out the case for securing the highest levels of production we can from land and water already farmed, in order to spare remaining wilderness from cows, plows, chainsaws, and trawler nets.
“Most species fare much better if habitats are left intact, which means reducing the space needed for farming. So areas that are farmed need to be as productive as we can possibly make them,” he said.
Some species flourish on conventional agriculture, especially in Europe, where modest livestock grazing can mimic “disturbance” created by massive prehistoric creatures, providing habitat for numerous species that would otherwise struggle. As a result, some low-yield farming should be considered, but only on a small scale, according to Balmford.
Balmford’s “three-compartment” model of harnessing high-yield farming in order to leave space for many more protected habitats, with pockets of traditional agriculture to preserve farmland-associated species, should form the basis of a new “Rural Land Use framework,” according to the UK Government-commissioned National Food Strategy (NFS), published in the summer.
Figuring out how to feed, clothe and power 11 billion people without causing mass species extinction and wrecking the climate is this century’s greatest challenge. Preserving diverse life while meeting humanity’s needs will mean enormous trade-offs, but the evidence is starting to point in one direction.
Andrew Balmford
If the UK is to fulfill its net-zero targets, the NFS estimates that roughly 21% of farmed land in England will need to be re-wilded or used for biofuel and that the bottom third of farmed land generates only 15% of English agricultural output.
Balmford’s most recent publication summarizes a decade of global research on crop productivity and biodiversity trade-offs. This includes Cambridge-led research on bird and tree species in India and West Africa, which found that while all species will suffer if mid-century food targets are met, more species will fare the best under extreme land sparing: concentrated farming that allows for more natural habitat.
“Colleagues have replicated these findings in field sites ranging from Mexico and the Pampas to Colombia and Kazakhstan,” said Balmford. “Most species are specialized to particular environments. Even minor disruptions reduce their populations. This is why so many species decline even with gentler farming.”
Retaining and expanding habitats to create patchwork landscapes of nature and primarily high-yield farming will allow species to “seed” and repopulate entire regions and nations, not just in isolated areas.
Balmford exemplifies the success of a four-square-kilometer restored wetland in Lakenheath in England’s east. Previously covered in carrot fields, the site is now a launchpad for egrets migrating northwards as a result of climate change, as well as the first breeding cranes spotted in The Fens in over 300 years.
In addition to the benefits to biodiversity, new research from the Andes, the United States, and the United Kingdom suggests that “land sparing” can help battle climate change since carbon storage levels are higher when high-yield cultivation allows for more natural vegetation.
Balmford’s previous study predicts that reserving 30% of UK land for woodlands and wetlands may store enough carbon to offset practically all UK farming emissions by 2050 while also providing a massive boost to British wildlife.
According to Balmford, support for “land sparing” does not imply full support for industrial development. Supporting smallholder farmers and adopting nature-based agricultural science are also important parts of increasing farm productivity.
For instance, when millions of Chinese farmers adopted a simple system that matched practices to local soil and weather circumstances, yields increased by 11% while fertilizer use decreased by a sixth.
Carp farming in rice fields, where the fish eat pests, produce fertilizer through feces, and serve as an extra crop, is one of several options for utilizing natural ecosystems. Emerging technologies, such as rice with increased photosynthesis, give hope for long-term high yields.
Researchers have lately applied the concept of “land sparing” to explore recreation, forestry, and even urban planning, with early results pointing to this method as the most viable way of meeting human demands with the least amount of environmental impact.
The consequences of tourism on wildlife tend to be lessened by confining visitation to wild regions into tiny areas of the landscape, whereas New Zealand is already “sparing” its forests: over 70% is now protected, but lumber is intensively exploited from pockets of pine plantation.
According to preliminary studies, the “sparing” ideology may potentially provide promise for depleting oceans. Aquaculture farming and regionally intensive fishing could offer enough “output” to allow for a rapid extension of “no-take” Marine Protected Areas while avoiding the expenditures of regulating equipment and catch sizes throughout all open water.
Support for high-yield approaches, on the other hand, must be linked to habitat conservation or restoration rather than being exploited for profit. In India and the Brazilian Amazon, linking financial support for smallholders or access to high-value markets with land-use limitations that preserve forests has already proven successful.
According to Balmford, public pressure on industry and government to commit to preserving land for nature will be critical. The groups that cause the most damage to environments, such those that cause emissions, may find it increasingly harder to hide. “Some giant corporations, often the worst offenders for land conversion, are actually in a position to think longer-term than many democratic governments,” he said.
Balmford’s research was influenced by David MacKay, a Cambridge polymath who died of cancer in 2016 at the age of 48. Mackay had a straightforward approach to sustainability, believing that low-carbon programs can only be properly compared at the same output level.
Without it, humanity risks being diverted by alternatives that fall short of addressing energy demands. Farming methods, likewise, can only be effectively compared when they are really providing society’s food needs.
“You can’t convince people to save nature if they are hungry. We need to ensure we can harvest enough from the biosphere while preserving the planet,” said Balmford. “Conservation has to be pragmatic if we are to interrupt an ecological catastrophe.”
