Could global warming make it more difficult to find a great cup coffee in the morning? It seems possible, as a new study finds that climate change could drive wild Arabica coffee into extinction in the next 70 years.
Arabica coffee is grown all over the world, but it originated in the highlands of southern Ethiopia, where the wild plants have always had a restricted range. Scientists from Ethiopia and Kew Gardens in the United Kingdom took a look at those ranges under various climate change models to see how the coffee would be impacted. They found that in even the best-case scenarios, wild Arabica would lose 65 percent of its suitable habitat before the end of the century. In other models, that number rose to 99.7 percent.
The scientists warn that these predications are on the conservative side, since climate change models do not factor in deforestation — Ethiopia's human population has nearly doubled in the past 40 years — or changes in wildlife distribution, such as the presence of migrating birds that help distribute the coffee plants' seeds.
The effect, according to the researchers, will not be limited to wild Arabica plants. Arabica is the only coffee cultivated in Ethiopia, where it plays an important role in the country's economy. Coffee there is harvested from plantations, semi-domesticated forest sites and the wild. All of those sources could be affected.
Meanwhile, climate change will also pose a threat to Arabica production around the world. The scientists found that the Arabica grown on plantations worldwide has a limited genetic diversity, making it more susceptible to the direct effects of climate change or to pests and diseases, which could also accompany global warming. This makes the wild plants in Ethiopia even more important as a source of broader genetic material for cultivated coffee, as they contain an estimated 95 to 99 percent of the species' total genetic diversity.
Although all of this sounds scary, the authors say they do not want the study to incite fear. "The objective of the study was not to provide scaremonger predictions for the demise of Arabica in the wild," said lead author Aaron Davis, head of coffee research at Kew Gardens, the famous royal botanical site. "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."
Co-author Justin Moat, head of spatial information science at Kew, said "this should alert decision makers to the fragility of the species."
This new research, published Nov. 7 in the journal PLoS One, is part of an ongoing program from Kew to study the world's plants, including both threatened species and those that have a high cultural or economic importance.