Scientists from the UK's Royal Botanic gardens at Kew, working with colleagues in Ethiopia, have suggested climate change along could lead to the effective extinction of one of the world’s favourite varieties of coffee before the end of the current century.

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Wild Arabica coffee, is considered important for the sustainability of the coffee industry due to its considerable genetic diversity, whereas Arabicas grown in the world's coffee plantations are from very limited genetic stock and are unlikely to have the flexibility required to cope with climate change and other threats, such as pests and diseases. In Ethiopia, the largest producer of coffee in Africa, climate change will also have a negative influence on coffee production in general.

In September, researchers from the United States revealed that the removal of trees from traditional agroforests where coffee is growing is having an impact on the sustainability and stability of agricultural systems and important wildlife populations. They said agroforestry (a sustainable farming practice that uses trees to support growing by fixing nitrogen, providing shade, improving soil structure and providing shelter for beneficial wildlife and insect life) is necessary to support biodiversity and sustainable production in tropical regions. 

As coffee, one of the world’s staple foodstuffs, is sensitive to climatic fluctuations, a change of just a few degrees in temperature could have devastating effects. The Kew scientists used computer modelling to study the potential impacts on coffee plants. They said theirs is the first such study, despite heightened concern about climate change and the effectiveness of current adaptation strategies in coffee-growing regions.

Computer modelling paints bleak picture for arabica

The Kew scientists said their modelling-based estimates remain conservative, as they do not take into account the effect of widespread deforestation occurring in coffee-producing regions. They added that other factors, such as pests and diseases, changes in flowering times, and perhaps a reduction in the number of birds (which disperse coffee seeds), are not included in the modelling either, and "these are likely to have a compounding negative influence."

Even so, their projections show wild Arabica could become extinct by 2080 if climate change continues as predicted.

Their findings show that, by this time, at best 65 percent areas suitable for wild Arabica, or that which is not subject to adaptation methods, will have disappeared. At worst 99.7 percent of suitable areas will no longer be able to support Arabica. The scientists concluded that the effect of climate change would "place natural populations under severe environmental stress, leading to a high risk of extinction."

The Kew scientists said the patterns they have predicted may already be observable, claiming that "Despite a recent dip, coffee prices are still the highest they have been for some 30 years, due to a combination of high demand and poor harvests. It is perceived by various stakeholders that some of the poor harvests are due to changed climate conditions, thus linking price increases to climate change."

The authors hope their research will form the basis for developing strategies for the survival of Arabica in the wild. It identifies a number of core sites, which might be able to sustain wild populations of Arabica throughout this century, serving as long-term in situ storehouses for coffee genetic resources. In many areas of Ethiopia loss of habitat due to deforestation might pose a more serious threat to the survival of Arabica, although it is now clear that even if a forest area is well protected, climate change alone could lead to extinction in certain locations. The study also identifies populations that require immediate conservation action, including collection and storage at more favourable sites (for example in seed banks and living collections).

Aaron Davis, Head of Coffee Research at the Royal Botanic Gardens, Kew, commented, "Coffee plays an important role in supporting livelihoods and generating income, and has become part of our modern society and culture. The extinction of Arabica coffee is a startling and worrying prospect. However, the objective of the study was not to provide scaremonger predictions for the demise of Arabica in the wild. The scale of the predictions is certainly cause for concern, but should be seen more as a baseline, from which we can more fully assess what actions are required."

Tadesse Woldemariam Gole, from the Environment and Coffee Forest Forum in Ethiopia, said, "As part of a future-proofing exercise for the long-term sustainability of Arabica production it is essential that the reserves established in Ethiopia to conserve Arabica genetic resources are appropriately funded and carefully managed."

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