A Critical Conversation on Climate Change ... - Green Choices

250 development dialogue september 2006 – carbon tradingBut can’t you cover such unknowns just by taking the amount of carbon youthink you might be sequestering and reducing the fi gure by a certain percentage,just to be on the safe side?That’s what many carbon accountants do. The FCCP study, for example,suggests a 20 per cent deduction from the figure designating total potentialof carbon sequestered to compensate for political and social risks anda 10 per cent deduction to compensate for technical forestry risks.The problem with such ‘risk-discounted’ figures is that carbon sequestrationis characterised by far more than just risk (see Chapter3). Uncertainty and scientific unknowns are other realities that biologicalcarbon accounting has to cope with. 53 In these conditions, it’simpossible to be sure whether any particular numerical risk factor isconservative enough to compensate for the unknowns involved.In Costa Rica, for instance, most monoculture tree plantations areless than 20 years old, with a trend towards planting just two species– Gmelina arborea and Tectona grandis. Pest or disease epidemics cantherefore be expected, but their extent is incalculable. Furthermore,El Niño climate events may propagate enormous fires whose extent,again, cannot be calculated in advance. During the dry season of1998, in the humid tropical zone where uncontrollable fires had neverbeen reported before, over 200,000 hectares were burned. Part of thisterritory is under monoculture tree plantations. Given such realities,it’s unsurprising that the FCCP carbon project study could give noreasons for its ‘technical’ risk figure of 10 per cent.At present, there is also little basis for guessing how much carbonsequestered in Costa Rican trees will re-enter the atmosphere andwhen. The FCCP study simply assumes that 50 per cent of the carbonsequestered by a given project will remain so once the timber hasbeen sold and used. However, the most common plantation speciesin the country (Gmelina arborea) is logged at least once every 12 yearsand most of the timber is used to manufacture pallets to transport bananas.The pallets are thrown away the same year they are made andprobably store carbon no longer than a few years – though no one hasdone the empirical studies necessary to be sure.The FCCP study also assumes that anthropogenic activities to fosternatural seed nurseries will result in secondary forests that will be inplace for at least 50 years. Accordingly, they make no deductions forre-emission of carbon. However, although current forestry law prohibitstransforming forests into grasslands, both legal changes and illegaluse could result in large re-emissions whose size would be impossibleto determine in advance.A 12-year-old plantationof Terminalia trees. Thecarbon released from erodedsoils, such as appear in thephotograph, is often missingin project accounts.