ABSTRACT
The structure of correlations among growth rates for the seven chemicals at a single time, and for single chemicals over time, may be complex. Both substitution and complementarities are observed among specific potential ozone depleters in certain applications. This chapter explains how subjective probability distribution for the production growth rates of the seven chemicals over the period 1985 to 2040 was chosen. Sources of uncertainty in the intensity of use of each chemical are assumed to be uncorrelated between chemicals, both within and across periods, although it would be possible to incorporate relationships of this kind by introducing additional component variates. Reliance on detailed analyses of individual chemical applications and markets is much less appropriate in the post-2000 than the pre-2000 period. The general economic growth component is common to all of the chemicals, and creates a positive covariance among the growth rates for all of the chemicals.
