The accident that led to the discovery of climate-change-proof coffee

The round plastic container in William Solano’s hands holds the coffee blend of the future. It’s not a novel macchiato or a whole-bean medium roast from a boutique shop: it’s a new hybrid variety of coffee that might fare better in our changing climate.

“This one is called Centroamericano,” says Solano, a coffee breeder at the Tropical Agricultural Research and Higher Education Center (CATIE), in Costa Rica, as he shows me a petri dish with dozens of plant embryos that look like tiny popcorn. Experts like him create hybrids by combining two genetically distant and complementary coffee strains, hoping to get the best characteristics from each parent.

Centroamericano was not created with climate change in mind. Its breeders were aiming for disease resistance, yield, and taste. And on those terms, Centroamericano was already a success story. It produces a high-quality beverage, yields over 20% more coffee beans than average per hectare, and shows high tolerance to coffee leaf rust, a much-feared plague. But one winter, the bean revealed a surprise. On the night of February 6, 2017, at a trial site in Laos where dozens of coffee varieties were being tested, temperatures dropped so dramatically that frost blackened and severely injured most of the trees in the plot. By 7 a.m., only a few survived: among them were Centroamericano and two other hybrid varieties from Central America.

Scientists are now realizing that such hybrids might be better at withstanding the temperature extremes likely to be brought on by climate change. A 2015 study by Christian Bunn and colleagues at the International Center for Tropical Agriculture (CIAT) calculated that under a midrange estimate of how severe climate change will be, the global area suitable for coffee will shrink about 50% by 2050, even as demand increases. “With a changing climate, suddenly weather-related stress become much more important,” says Bunn.

So why did the hybrids survive? When parents contribute very different genes to an offspring, as in their case, the resulting organism possesses what scientists call “hybrid vigor.” “It’s a widely known effect in other areas, but no one had studied it in coffee,” says Benoît Bertrand, a researcher for the French Agricultural Research Centre for International Development and a leading authority on coffee breeding. Although the concept is often used in maize production and is fairly common in poultry and rice, it was Bertrand’s team that initially applied it to coffee in the 1990s, creating Centroamericano and a handful of other hybrids.

This vigor is critical for coffee, a crop notorious for its lack of diversity. The coffee grown in Latin America has an especially shallow genetic pool, making it particularly vulnerable. The region is dominated by two arabica varieties initially brought in by Europeans. Although dozens of different Latin American strains descended from them, at times mixing with a third arrival, entire generations of coffee trees have been effectively intermarrying with their cousins.

Bertrand’s team wanted to break this genetic bottleneck. Working with CATIE and with Central America’s national coffee institutes, they created what are known as “F1 hybrids”—first-generation offspring of two genetically distant parents— by combining the best local varieties with genetically diverse Ethiopian strains from CATIE’s collection. They did this manually, by taking pollen from one plant and pollinating flowers from another, which means these varieties are not considered genetically modified organisms (though such breeding is just a more ancient form of genetic modification).

When results came in from trial sites, the data showed vastly superior performance from the new varieties. Their hybrid vigor was 20% to 50% higher than their parents’, yield was up, and some varieties were disease-tolerant. “The hybrids are boxing in a different category,” says Christophe Montagnon, scientific director of World Coffee Research (WCR), a nonprofit that ran the trial in Laos where Centroamericano showed its resilience.

F1 hybrids sound great, but they’re expensive. You can’t take their seeds and plant them, because their genes aren’t stable; in a first-generation offspring from two genetically distant strains, if you plant 100 seeds you’ll get many different types of trees as the parents’ genes reshuffle to create new combinations. “You will lose all the stability of the hybrid—all the vigor,” says Lucile Toniutti, a molecular breeder at WCR.

Experts have to choose one specific plant they like and clone it in a lab. This involves cutting leaves into bits and placing them in a growth hormone so they balloon into the embryos Solano showed me at CATIE. The process takes over 18 months and consumes loads of cash: each F1 hybrid seedling can cost around 80 US cents, which is two to three times pricier than traditional varieties.

It’s a crucial problem to solve, because 1.8 million people around Central America, both farmers and the seasonal workers who harvest the beans, depend financially on coffee. While some farmers might be able to switch to cocoa, rubber, or other crops, says CIAT’s Bunn, many people would be forced out of rural communities. Many would seek to migrate north to Mexico and the US.

“I am 100% certain that the future of coffee depends on hybrids’ success,” says Solano. In March, he drove to Starbucks’s experimental coffee farm in Costa Rica to deliver 50 new hybrids to be tested. More varieties will come, from his lab and others, and breeders will increasingly focus on resilience to climate change.

And if the hybrids don’t stand up to climate change as well as hoped? “Our most pessimistic predictions will be made reality,” he says.