Climate change is expanding the amount of land suitable for farming in colder regions. While farming such areas could offset declines in crop yields elsewhere, it would also pose a threat to wild places once protected from cultivation by the cold.
As the planet warms, researchers expect farmers will have to adapt to achieve crop yields sufficient to feed a growing global population. “I would say that’s inevitable,” says Alexandra Gardner at the University of Exeter in the UK.
That could mean farming different crops, planting at different times, using more irrigation and fertiliser or growing in different places. One study found that with very high fossil fuel emissions, the world’s bread baskets – regions responsible for producing a large proportion of our food – would need to shift toward the poles by around 600 kilometres before the end of the century to maintain current yields.
While that shift could help offset climate-related declines in yields nearer to the equator, it could also pose a threat to vast wilderness areas and the intact ecosystems they host.
Gardner and her colleagues modelled how climate change under different emissions scenarios would alter the areas appropriate for growing more than 1700 varieties of major crops, including potatoes, wheat and cotton. They then looked at where the newly suitable agricultural regions overlapped with “wilderness”, defined as large spaces free from human pressures.
They found that under a moderate emissions scenario, 1.85 million square kilometres of wilderness became newly-suited for at least one crop by mid-century. Under a very high emissions scenario, 2.75 million square kilometres of wilderness became farmable, amounting to 7 per cent of all the wilderness outside Antarctica.
This overlap disproportionately occurred in the northern hemisphere, both because of the large amount of wilderness remaining there as well as the more rapid warming in higher latitudes. Some of the largest overlaps occurred in Russia, Canada and Alaska.
Gardner says the models don’t account for numerous other factors that would affect whether crops could actually be grown in these areas, such as soil quality or proximity to transportation networks. Uncertainties involved in modelling both future climate change and how particular crops will respond means the projections should be seen as a “first pass”, she says.
But researchers say the pattern of overlap suggests a clear problem. “This is a real threat that vast areas in northern latitudes – very important for biodiversity, carbon balance, hydrological cycle, etc – will be under pressure for food production,” says Matti Kummu at Aalto University in Finland, who wasn’t involved with the research.
Climate-related declines in areas currently used for farming nearer the equator could exacerbate this pressure. Under both emission scenarios, the researchers found around 6 per cent of the land currently suitable for farming will become unsuitable for any crop by the middle of the century, and half of all land will see declines in the diversity of edible plants that would be able to grow there.
More efficient use of current agricultural land – for instance, by using less of it to raise livestock and encouraging consumers to shift towards a more plant-based diet – could help avoid this pressure. So would reducing emissions to mitigate climate change. But Elisabeth Moyer at the University of Chicago says adaptations on existing farmland probably won’t be enough to meet demand for food on their own. “In the real world, unless the seed breeders save us, we’re going to have to let things move around.”