Increasing uncertainty from chain multipli-
cation is particularly important for estimating the
bene®ts of deforestation avoidance. For example,
if estimates of the number of hectares cleared,
tons of biomass per hectare and carbon emission
per ton of biomass each has a coecient of vari-
ation of 20%, the cv of the result would
increase to 34.6% as a result of the two multipli-
cations. If an additional link in the chain were
added with the same 20% cv, say for methane
emission per ton of carbon emitted, the cv of the ®nal result would increase to 40%, or double the
cv of each component; an additional multiplication would raise it to 44.7%