32 • Climate Change • C&CI March 2012
Shade-grown coffee could offset emissions along the value chain
T
he main way to estimate this effect is by calculating the carbon foot- print. The few studies that have been published of the coffee carbon footprint indicate that around 55 per cent of the emissions (FUNCAFE 2006, PCF 2008) come from the agronomic prac- tices on the farms where the coffee is produced.
At the same time, at least on shaded coffee farms, there are considerable stocks of carbon in the biomass of the shade trees and the conservation of soil organic matter. Other sustainable man- agement practices – much promoted in coffee production – may reduce emis- sions or even sequester more carbon. The question in many minds is ‘do the carbon stored in shaded coffee systems and emissions reduced by sustainable practices compensate for emissions on the farm, and could it do so across the whole value chain?’
The ideal situation would be if sustain- able production practices on-farm could offset – or in current terminology "inset" – carbon emissions from the whole supply chain, to achieve the ideal of a ‘carbon neutral’ value chain. Is this a possibility, or wishful thinking?
Carbon storage and shade coffee
The stocks of carbon stored in coffee systems vary according to shade type, as can be seen from figure 1. Full sun coffee has less than 10 tonnes of carbon stored; ordinary shaded coffee may accumulate 20-30 tonnes of carbon with the addition of shade trees; but systems with large forest trees can accumulate 70-80 tonnes of carbon per hectare. These systems may even approach the 100 tonnes per hectare or more of car- bon stored in natural forest. Without doubt, conserving these stocks is extremely important, and their loss should the coffee system be ‘inten-
Shade-grown coffee could have the potential to offset on-farm emissions and those that originate elsewhere in the value chain
sified’ with more regulated shade would be almost the same as bad as deforesta- tion. Carbon stocks such as these have
Producing, processing and distributing coffee generates green- house gases that contribute to global warming, but as Jeremy Haggar1 and Martin Noponen2 suggest, growing coffee under shade can help abate on-farm emissions, and could even offset emissions elsewhere in the value chain
accumulated over many decades. What is more difficult to estimate is which sys- tems are accumulating carbon that may be used to offset against emissions. This would require measuring carbon stocks say, every 3-5 years, in order to estimate how much carbon stocks have increased, or the annual carbon seques- tration.
Currently, we only have estimates of the increase in carbon stocks from sites where coffee and shade trees have been established on bare ground, in areas that were already deforested. In these cases we know that carbon stocks can accu- mulate 3-12 tonnes per hectare per year in above ground biomass or 10-40 tonnes of CO2
equivalents – the usual
measure of carbon trading. These levels of sequestration are generally above the agronomic carbon footprint of 2-5 tonnes of CO2
equivalents from coffee produc- tion (Noponen 2012).
Figure 1. Carbon stocks in above ground biomass with no shade (full sun) and different kinds of shade compared to a natural forest in southern Guatemala (Idol et al 2011)
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