The Arabicas grown in the world’s coffee plantations are from limited genetic stock and are unlikely to have the flexibility required to cope with climate change and other threats, such as pests and diseases, found the researchers.
In Ethiopia, the largest producer of coffee in Africa, climate change will also have a negative influence on coffee production.
The study, which uses computer modelling, represents the first of its kind for wild Arabica coffee. The researchers used field study and ‘museum’ data (including herbarium specimens) to run bioclimatic models for wild Arabica coffee, in order to deduce the actual (recorded) and predicted geographical distribution for the species. The distribution was then modelled through time until 2080. The models showed a profoundly negative influence on the number and extent of wild Arabica populations.
A visit to South Sudan (Boma Plateau) in April 2012 provided an opportunity to test the modelling predictions via on-the-ground observation. On comparing these observations with a study on Arabica made on the Boma Plateau in 1941, it was clear that not all of the environmental stress evident could be attributed to deforestation or agriculture over the 70 year period. The modelling predicted that Arabica could be extinct in these forests by the year 2020, due to climate change, and this appears to be realistic given the poor health (lack of seedlings, loss of mature Arabica specimens, low frequency of flowering and fruiting) of the remaining populations observed in 2012.
The outcome of climate change in Ethiopia for cultivated Arabica, the only coffee grown in the country, is also assumed to be profoundly negative, as natural populations, forest coffee (semi-domesticated) and some plantations occur in the same general bioclimatic area as indigenous Arabica.
It is hoped that the study will form the basis for developing strategies for the survival of Arabica in the wild.
Aaron Davis, Head of Coffee Research at the Royal Botanic Gardens, Kew, said, "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."