Review of Methyl chloroform Distributed Emissions from the Global Emissions Inventory Activity (GEIA)

This enabled sales to be assigned to countries on the basis of each national share of the total regional Gross Domestic Product, as described in Midgley and McCulloch (1995). This use of relative GDP as a distribution function was shown to be valid for fluorocarbon solvents in McCulloch et al. (1994). Within each country, emissions were assigned to gridsquares using the population distribution in Li (1996).

Results are presented here as the percentage distribution among gridsquares. Absolute emission from each gridsquare in 1990 should be calculated by multiplying global emission for 1990 in Table 1 by the gridsquare percentages in Table 2(Keene et al., 1999). For other years, the distribution in Table 2 (download Table 2) should be applied to the global emission for the appropriate year.

While global emissions change relatively rapidly, distribution is affected only by relative economic activity and population dynamics, which have slower rates of change with time. It is expected that the distribution can be applied to the years 1985 to 1995 without significantly increasing uncertainty but this has not been tested. It can be applied to years beyond this range only with caution and new distributions for more recent years are under development.

Based on McCulloch and Midgley (2001) the time series (1951 to 2000) of methyl chloroform emissions and their uncertainties is shown in Table 1 (geiacenter.org/ reviews/mcfTabl1.html). Future emissions will be governed by the controls required by the Montreal Protocol and by the quantity of material currently in the "bank" (that is: material which is in use but has not yet been emitted). A scenario for future releases of CFC-11 was described in Madronich and Velders (1999).

This scenario has been updated to take account of the significant reduction in productive capacity that has occurred in recent years and will be published in Fraser and Montzka (2003).