Coffea arabica yields decline in Tanzania due to climate change: Global implications

Abstract

tCoffee is the world’s most valuable tropical export crop. Recent studies predict severe climate changeimpacts on Coffea arabica (C. arabica) production. However, quantitative production figures are necessaryto provide coffee stakeholders and policy makers with evidence to justify immediate action. Using datafrom the northern Tanzanian highlands, we demonstrate for the first time that increasing night time(Tmin) temperature is the most significant climatic variable responsible for diminishing C. arabica yieldsbetween 1961 and 2012. Projecting this forward, every 1◦C rise in Tminwill result in annual yield lossesof 137 ± 16.87 kg ha−1(P = 1.80e-10). According to our ARIMA model, average coffee production will dropto 145 ± 41 kg ha−1(P = 8.45e-09) by 2060. Consequently, without adequate adaptation strategies and/orsubstantial external inputs, coffee production will be severely reduced in the Tanzanian highlands inthe near future. Attention should also be drawn to the arabica growing regions of Brazil, Colombia, CostaRica, Ethiopia and Kenya, as substantiated time series evidence shows these areas have followed strikinglysimilar minimum temperature trends. This is the first study on coffee, globally, providing essential timeseries evidence that climate change has already had a negative impact on C. arabica yields.