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Our morning cup of coffee is under threat from climate change, scientists have warned. Although projections vary on the crop’s capacity to adapt to rising global temperatures, it is certain that the areas with a suitable climate for coffee cultivation will significantly shrink in the upcoming decades, challenging global production capacity. Moreover, heatwaves and unreliable rainfall generate conditions in which pests and diseases that can devastate coffee plantations thrive, such as coffee leaf rust.

Coffee is one of the most traded commodities in the world, consumed by one third of the global population. But while climate change will deprive caffeine-hooked consumers; the worst consequences will be felt by around 125 million people directly involved in coffee production and trade, including many smallholder farmers who depend on it to secure their livelihoods.

Facing an uncertain future, major coffee companies and concerned public entities have mobilized funding to support innovation and adaptation initiatives to ensure the industry continues to thrive. However, they might be overlooking a hidden treasure in Africa’s tropical forests.

Global coffee production is based on two species: Coffea arabica, known as Arabica coffee, and Coffea canephora, or Robusta coffee. Arabica, which grows in cool high-altitude climates, is the most expensive and appreciated species, used in specialty coffee and high-grade blends. Robusta, which grows in hot and humid climates, is in general less appreciated, found in cheaper blends and as instant coffee.

Because Arabica production is more profitable, most coffee research focuses on this variety, but scientists with the Meise Botanic Garden (Meise BG) in Belgium are challenging the trend, suggesting that the more resistant Robusta might instead hold the key to the coffee industry’s future.

Baristas’ ugly duckling

While Coffea arabica was first discovered in Ethiopia, Coffea canephora’s natural habitats are West and Central Africa’s tropical forests. In fact, recent genetic studies show that Coffea arabica is a hybrid of Coffea canephora and Coffea eugenioides – both species naturally occurring in the Congo Basin, thus making it the homeland of modern coffee production.

However, while Arabica was cultivated as early as the 12th century, Robusta plantations only popped up at the beginning of the 20th century as Europeans took interest in the genetic diversity found in Africa, which could lead to improved production in Asia and other tropical regions. Currently, it is estimated that 40 percent of the world’s consumed coffee beans are Robusta.

“Because Robusta has more caffeine and a more pronounced bitter flavor, it is less appreciated by consumers,” explained Filip Vandelook, researcher at Meise BG. “But in fact, there is potential to develop higher quality Robusta, for example, through breeding with wild populations.”

“Because Robusta thrives in warm and humid climates, and a low altitude, this species might be less vulnerable to climate change,” added Piet Stoffelen, director of Collections at Meise BG and an expert in coffee diversity in Central and West Africa. Therefore, according to him, Robusta’s market share will grow, and within 10 years it could represent more than 50 percent of global coffee production.

If more investments are made in Robusta’s pre- and post-harvest processing optimization, this species could become more appreciated by consumers and profitable for farmers, explained Vandelook. “Robusta’s potential remains largely understudied – and that’s what we are trying to change.”

   Robusta coffee has more caffeine and a more pronounced bitter taste. Photo: Axel Fassio/CIFOR

The Congo Basin’s botanic treasures

Supported by the European Union, and in partnership with the Center for International Forestry Research (CIFOR), Meise BG specialists are working in the Democratic Republic of Congo (DRC)’s Yangambi Biosphere Reserve to discover the secrets of forest coffee.

This 235,000 ha forest reserve, located in northeast DRC, once hosted the world’s most reputable research station for the study of tropical agriculture. In its heyday, from the 1930s until 1960, the center hosted an important coffee program specialized in Coffea canephora. Botanists developed a well-documented live collection of wild coffee species, classified hundreds of dried coffee leaves in a world-class herbarium, and conducted many breeding experiments to develop a crop that would be more resistant to unpredictable climate and pests.

But as DRC descended into decades of political instability and conflict, most of this knowledge was lost. Although the living collection and dried samples remain, they need to be revived and modernized. Moreover, the center’s infrastructure needs urgent renovations to facilitate new research and conservation of these important genetic resources.

This is why Meise BG is working with the Congolese Institute for Agronomic Studies (INERA) to ensure that Yangambi will once again become an international hub for the study and conservation of coffee.

“DRC’s existing resources are a strong foundation to put it at the forefront of Robusta research,” said Stoffelen.

   Yangambi’s live collection contains Robusta and wild coffee species. Photo: Axel Fassio/CIFOR

“We are renovating the infrastructure, updating the collections, and digitalizing the dried samples,” added Vandelook. “But most importantly, we are launching new research to better understand Robusta’s potential to thrive in a climate change context.”

Consequently, Meise BG’s team of Congolese and Belgian researchers is studying Yangambi’s wild coffee species and providing new genetic resources in a quest to improve Robusta’s properties.

“A simple walk in Yangambi’s forest can lead you to the discovery of new species,” said Bienfait Kambale, a botanist with Meise BG. “The natural wealth of this place is highly relevant to solve the challenges that coffee faces today.”

   Yangambi’s coffee propagation batteries will soon be rehabilitated. Photo: Axel Fassio/CIFOR
   Bienfait Kambale studies Yangambi’s herbarium coffee collection. Photo: Axel Fassio/CIFOR

A fresh start

Until the late 1980s, DRC was one of the world’s most important coffee producers, but output gradually declined during the Mobutu regime and the subsequent wars. However, as the country stabilizes, DRC’s coffee industry is once again slowly taking off. The eastern part of the country, characterized by a mild weather and hilly landscapes, provides the perfect setting for Arabica plantations. However, there is also an enormous potential to grow coffee in the country’s lowland regions, according to Meise BG scientists.

“We hope that in the near future our research can support producers and contribute to develop DRC’s coffee industry,” said Vandelook.

“Coffee production could support DRC’s economy and become a driver of development – with Yangambi playing an important role,” added Stoffelen.

   Ithe Mwanga Mwanga adds new wild coffee species to Yangambi’s herbarium. Photo: Axel Fassio/CIFOR
This research was supported by the European Union
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Topic(s) :   Climate change