A triple whammy of disease, climate change, and deforestation has threatened around 60 percent of the planet's wild coffee species. While this hasn't yet imperiled the world's coffee supply, it jeopardizes your favorite coffee's resiliency in the face of profound planetary change.

In new research published Wednesday in Science Advances, botanists and plant researchers determined that 75 of 124 wild coffee species are now threatened with extinction, based upon widely-used International Union for the Conservation of Nature (IUCN) criteria. For the coffee drinker, this matters: Experts emphasize that wild species hold the key to maintaining a healthy, vibrant, and flavorful coffee supply.

"The coffee we drink today exists because of access to wild species," Aaron Davis, the senior research leader for Plant Resources at The Royal Botanical Gardens Kew and lead author of the study, said in an interview.

One of the two most popular coffee species that everyone drinks today, robusta, was barely even known until the early 1900s. It was just a wild species, growing in remote forests.

"It went from being almost unknown to being a major global commodity — that's amazing," said Davis.

Wild Arabica coffee. Image: Royal Botanic gardens kew

Like most every food commodity, coffee today is grown on farms. But its wild predecessors exist in specific regions, like Ethiopia and Sudan. And these regions are being hit hard.

In 2012, Davis and other coffee researchers visited south Sudan, the only place outside of Ethiopia that hosts the wild species of Arabica, which accounts for 60 to 70 percent of the world's coffee. Seventy years previous, coffee collectors had journeyed to this Sudanese land. They wrote that it teemed with wild coffee plants.

But things have changed.

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"It was dry as a bone — the landscape completely changed over 70 years," Hanna Neuschwander, the director of communications for World Coffee Research, an industry-funded agricultural organization for coffee, said in an interview.

There were few older plants and young seedlings there, said Davis, who noted the area has also been hit with deforestation.

"It's under huge pressure," he said. "If that [deforestation] carries on for another 10 years, there will be nothing left."

Losing these wild plant species — some of which haven't been seen in 100 years — wipes out a valuable gene pool that can be used to create coffee breeds with the ability to fend off the warming climate and the spreading of disease, which is already an established threat.

Aaron Davis surveying wild coffee. Image: emma sage

"The coffee industry is invariably going to face challenges that we’re aware of, and potentially challenges that we don’t know exist yet," said Neuschwander. "If you don’t have those wild species protected, you have probably crippled your ability to address the problem — because you just don't have the genetic toolkit."

Similar to many crops, like the essential ingredients in beer, the farmed coffee today is especially vulnerable to two of the most-well predicted and currently-unfolding consequences of climate change, increased heat and drought.

"Increasing greenhouse gases are warming the planet and changing patterns of extreme heat and drought," Nathan Mueller, an assistant professor of earth system science at the University of California, Irvine who researches global food security, said over email.

"As farmers are increasingly exposed to new climate conditions and changing pest pressures, the genetic diversity of wild crop relatives may be essential to breeding new coffee varieties that can withstand these pressures," Mueller, who was not involved with the study, added.

Both Arabica and robusta — which comprise nearly all the world's store-bought coffee — don't tolerate low moisture or drought. And Arabica doesn't do well in hotter than normal temperatures, noted Davis.

Due to climate change, previous research found that wild Arabica may go extinct in around 60 years.

"It's a longer term threat — but its shorter term than some people might imagine," said Neuschwander. "It sounds far away, but that’s in my lifetime," she added.

Average global temperature in 1884. Blues show below average. Image: nasa Average global temperature in 2017. Reds, yellows, and oranges show above average. Image: nasa

A critical conservation solution, though, would be to preserve the wild coffee seeds (and genes) in seed banks or collections. The researchers found that around 55 percent of wild species are preserved in gene banks. But but that doesn't yet provide relief, simply because these few seed banks aren't yet reliable, complete, or well-funded.

"Some of them literally just have handwritten notes on paper about the varieties they have in their collection," said Neuschwander.

The massive coffee industry knows it must address the problem, which could cost over $20 million dollars, she noted.

But such is the reality in a coffee world threatened by disease, pestilence, and accelerating climate change.

"There's a growing awareness that this industry's success — which is worth billions of dollars — is contingent on the health of the plant," said Neuschwander.