Up to half of cropland in low-latitude regions could become unsuitable for the food crops currently grown there as the planet continues to warm, according to a study led by researchers at Finland’s Aalto University. The research, published in Nature Food and still widely cited in food-security literature through 2026, modelled the climate suitability of 30 major food crop species and found the risk concentrated overwhelmingly in the tropics rather than spread evenly across the globe.
Sub-Saharan Africa faces the steepest losses of any region studied, with up to three-quarters of current production at risk if global warming exceeds 3 degrees Celsius above pre-industrial levels, the study found. Lead researcher Sara Heikonen and senior author Matti Kummu concluded that around a third of global food production overall could be affected, with staple crops including rice, maize, wheat, potato and soybean, which together account for more than two-thirds of humanity’s food energy, among the most exposed.
Crop diversity itself is at stake
The study’s central finding goes beyond simple yield loss. Researchers found that warming threatens the range of crop species that remain viable in a given location, not only the productivity of crops already grown there. “The loss of diversity means the range of food crops available could decrease significantly in certain areas,” the researchers noted, a distinction that matters because crop diversity itself functions as a buffer against pests, disease and localised weather extremes.
Mid- and high-latitude regions, by contrast, are expected to retain more of their current productive capacity and, in some cases, gain new viable crop options as warming shifts growing conditions. That asymmetry mirrors a pattern seen elsewhere in climate research: tropical and low-latitude ecosystems tend to be pushed further outside their historical operating range than temperate ones, leaving less biological margin before thresholds are crossed. A recent global coral reef assessment found a structurally similar pattern, with tropical reefs losing the ability to recover between bleaching events even as some temperate and refugia reef systems fared comparatively better.
Caveats the researchers themselves flagged
The Aalto team was explicit about the limits of their modelling. Their projections do not account for new pests or extreme weather events that warming could introduce, both of which could worsen outcomes beyond what the crop-suitability model alone predicts. Nor does the study assume any particular pace of adaptation, whether through breeding drought and heat-tolerant varieties or through farmers shifting to different crops altogether, both of which are already under way in various forms across the regions studied.
Efforts to develop climate-resilient seed varieties, including a new wheat variety launched in Zimbabwe this week and considerable public breeding investment in India, represent exactly the kind of adaptation the study’s baseline scenario does not fully capture. Whether such breeding programmes can outpace the rate of climate suitability loss the study describes remains an open empirical question rather than a settled one.
The study’s authors have called for its findings to inform where breeding investment and agricultural adaptation funding are targeted, arguing that regions facing the steepest projected losses, chiefly sub-Saharan Africa, currently receive a disproportionately small share of global agricultural research funding relative to the scale of risk they face.
That funding gap has practical consequences already visible on the ground. Public agricultural research institutions across the region report that breeding programmes for heat- and drought-tolerant staple varieties often take a decade or more to move from initial trials to varieties available to farmers, a timeline that sits uncomfortably against a warming trend the study suggests is already narrowing the window for adaptation. Some of that gap is beginning to close through initiatives such as newly launched climate-resilient seed varieties in Southern Africa, though researchers caution that isolated breeding successes will not offset the scale of risk the modelling describes without a substantial increase in sustained funding.
