About 60% of the coffee we drink is sourced from Coffea arabica, a delicate variety that experts predict could dwindle by up to 80% by 2050, under the effects of climate change.
But the solution may be in plain sight—and the clue’s in its name: Coffea robusta, which makes up the remainder of coffee consumption worldwide, also happens to be more adaptable to variable climate conditions, and continues to produce high yields.
Previous researchers have mapped out two possibilities to safeguard our beloved coffee reserves against climate change: adapting coffee farming to new environments, and identifying more climate-resilient species. In the new Crop Science study, the researchers claim their Robusta discovery enables us to do both.
This species has a larger genetic diversity than Arabica, and the researchers were curious about whether this would translate to more resilience in the field. To find out, they set about isolating various cultivars of this species, which collectively represented 27 genotypes. They grew these cultivars beside Arabica plants at multiple locations in the cooler highlands of Brazil, the world’s largest producer of Arabica coffee beans.
These cooler, drier locations are where Arabica is usually grown, but not Robusta, which is typically raised in warmer climes. The purpose of shifting altitudes was to examine the ‘plasticity’ of Robusta to different environmental conditions, which is another way of saying how well a plant functions under variable conditions.
Measures of a plant’s plasticity can be taken from traits like whether it can continue to produce high yields, as well as the effect on its flavor profile and taste—known as ‘cup quality’ in coffee-making. For all cultivars, the researchers tested these traits, growing the Robusta and Arabica crops across the varied locations over the course of four years.
By the end of this ambitious field trial, they had made some striking discoveries. First, that many cultivars of Robusta fared very well in the cooler, drier extremes of the Brazilian highlands. In one location in particular, they found that Robusta produced almost 75 bags of beans per hectare, which is similar to the average production of the species when it’s grown in optimal warmer conditions.
The researchers also identified five genotypes in particular whose plants remained stable under the cooler temperatures, indicating that these were particularly resilient to change. This suggests the researchers’ hunch was right: “Robusta is flexible because it has a large diversity and therefore different plants can be selected, depending on the weather conditions,” they say.
In principle, that means farmers could expand this lowland crop into the cooler highlands to replace Arabica, which might struggle to thrive in this landscape under climate change. And, Robusta has other benefits befitting its name. The crop requires less fertilizer and water to grow, it would be a more sustainable choice, and more attractive to farmers watching their bottom lines.
Bearing this in mind, along with the species’ adaptability to different temperatures, the researchers are now testing its plasticity in a completely different environment: Florida, where the already warm temperatures are set to rise. The Brazil-based research identified one additional Robusta genotype that responds particularly well to higher temperatures, suggesting that perhaps this species can straddle both cooler and warmer conditions, giving our morning cuppa some insurance against climate change.
The research is still only in its early stages, and despite the longevity of the recent investigation, the researchers note that the study sample was relatively small. Still, “the final message is clear and promising,” they write in the study. “The scope of genetic diversity in [Robusta] is large and can support a new generation of climate-smart cultivars that meet the current market demand.”
Ferrão et. al. “Robust and smart: Inference on phenotypic plasticity of Coffea canephora reveals adaptation to alternative environments.” Crop Science. 2024.
