Carbon footprints and CO2 removal in primary production of coffee: a meta-analytical review

Producing countries and value-chain participants are seeking to minimize the effect of coffee production on global warming. In support of this goal, we present a global review of carbon footprints and atmospheric-CO2 removal rates in primary production of coffee, based on 21 studies of carbon footprint and 16 with data on CO2 removal rate. We aimed to characterize typical values, identify determinants, compare arabica and robusta coffee, compare cropping systems, and suggest ways of reducing footprints and increasing CO2 removal rates. The median f interquartile range of carbon footprints of coffee production were 2954 +/- 3636 CO(2)e ha(-1) year(-1) (area carbon footprint, ACF) and 2.18 +/- 2.04 CO(2)e kg(-1) green beans (product carbon footprint, PCF). Manufacture and application of fertilizers, particularly nitrogenous fertilizers, were almost always the main emissions sources (65%-100% of the total). ACF was significantly higher in arabica than robusta, while ACFs of agroforestry and organic systems were <50% of those of unshaded and non-organic systems; these differences were also significant. PCF of organic production was significantly lower than that of non-organic production, but marginally so; no other significant differences in PCF were found. The median CO2 removal rate of unshaded production was 6990 f 3405 kg CO2 ha(-1) year(-1). For agroforestry production the median was much higher (17 676 +/- 3971 kg CO2 ha(-1) year(-1)). Removal rates of organic and non-organic production did not differ significantly. We present a generalized approach for reducing the overall global-warming effect of coffee production, consisting of 10 options for interventions within an overarching principle of zero deforestation. Wider use of agroforestry production and use of organic nitrogen sources are features of eight of the interventions. Implementation of the interventions will also require the building of enabling frameworks that allow farmers to meet climate-change mitigation goals without sacrificing productivity or profitability.