Christian Bunn

Projected Shifts in Coffea arabica Suitability among Major Global Producing Regions Due to Climate Change

Regional studies have shown that climate change will affect climatic suitability for Arabica coffee (Coffea arabica) within current regions of production. Increases in temperature and changes in precipitation patterns will decrease yield, reduce quality and increase pest and disease pressure. This is the first global study on the impact of climate change on suitability to grow Arabica coffee. We modeled the global distribution of Arabica coffee under changes in climatic suitability by 2050s as projected by 21 global circulation models. The results suggest decreased areas suitable for Arabica coffee in Mesoamerica at lower altitudes. In South America close to the equator higher elevations could benefit, but higher latitudes lose suitability. Coffee regions in Ethiopia and Kenya are projected to become more suitable but those in India and Vietnam to become less suitable. Globally, we predict decreases in climatic suitability at lower altitudes and high latitudes, which may shift production among the major regions that produce Arabica coffee.

Multiclass Classification of Agro-Ecological Zones for Arabica Coffee: An Improved Understanding of the Impacts of Climate Change.

Cultivation of Coffea arabica is highly sensitive to and has been shown to be negatively impacted by progressive climatic changes. Previous research contributed little to support forward-looking adaptation. Agro-ecological zoning is a common tool to identify homologous environments and prioritize research. We demonstrate here a pragmatic approach to describe spatial changes in agro-climatic zones suitable for coffee under current and future climates. We defined agro-ecological zones suitable to produce arabica coffee by clustering geo-referenced coffee occurrence locations based on bio-climatic variables. We used random forest classification of climate data layers to model the spatial distribution of these agro-ecological zones. We used these zones to identify spatially explicit impact scenarios and to choose locations for the long-term evaluation of adaptation measures as climate changes. We found that in zones currently classified as hot and dry, climate change will impact arabica more than those that are better suited to it. Research in these zones should therefore focus on expanding arabicas environmental limits. Zones that currently have climates better suited for arabica will migrate upwards by about 500m in elevation. In these zones the up-slope migration will be gradual, but will likely have negative ecosystem impacts. Additionally, we identified locations that with high probability will not change their climatic characteristics and are suitable to evaluate C. arabica germplasm in the face of climate change. These locations should be used to investigate long term adaptation strategies to production systems.

Winner or loser of climate change? A modeling study of current and future climatic suitability of Arabica coffee in Indonesia

Previous research has shown that the production of Arabica coffee (Coffea arabica), the main source of high-quality coffee, will be severely affected by climate change. Since large numbers of smallholder farmers in tropical mountain regions depend on this crop as their main source of income, the repercussions on farmer livelihoods could be substantial. Past studies of the issue have largely focused on Latin America, while the vulnerability of Southeast Asian coffee farmers to climate change has received very little attention. We present results of a modeling study of climate change impacts on Arabica coffee in Indonesia, one of the world’s largest coffee producers. Focusing on the country’s main Arabica production zones in Sumatra, Sulawesi, Flores, Bali and Java, we show that there are currently extensive areas with a suitable climate for Arabica coffee production outside the present production zones. Temperature increases are likely to combine with decreasing rainfall on some islands and increasing rainfall on others. These changes are projected to drastically reduce the total area of climatically suitable coffee-producing land across Indonesia by 2050. However, even then there will remain more land area with a suitable climate and topography for coffee cultivation outside protected areas available than is being used for coffee production now, although much of this area will not be in the same locations. This suggests that local production decline could at least partly be compensated by expansion into other areas. This may allow the country to maintain current production levels while those of other major producer countries decline. However, this forced adaptation process could become a major driver of deforestation in the highlands. We highlight the need for public and private policies to encourage the expansion of coffee farms into areas that will remain suitable over the medium term, that are not under legal protection, and that are already deforested so that coffee farming could make a positive contribution to landscape restoration.