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close this bookThe Global Greenhouse Regime. Who Pays? (UNU, 1993, 382 p.)
close this folderPart I Measuring responsibility
close this folder3 Assessing emissions: five approaches compared
View the document(introduction...)
View the documentIntroduction
View the documentComprehensiveness compared
View the documentAccuracy by category
View the documentRegional and national emissions by source
View the documentConclusions
View the documentReferences
View the documentAppendix A: Estimates of greenhouse gas emissions
View the documentAppendix B: Calculating cumulative and current emissions


In this chapter, I present a variety of ways to assess responsibility for greenhouse gas (GHG) emissions. The parameters that could define responsibility from a polluter pays perspective include: which greenhouse gases are counted; which sources are included; and what time frame is used for estimating them. A New Zealander who lives in a country with twenty methane emitting sheep for every person may prefer to keep the gases limited to carbon dioxide only. A Swiss citizen mostly emits carbon dioxide by burning fossil fuels, and may be unhappy if only this gas is controlled. And someone from a recently industrialized country such as Singapore might feel justified in pushing for the inclusion of historic emissions in global greenhouse negotiations. The definition of GHG emissions, therefore, has great practical impact on each country's relative responsibility for emissions. The feasibility of controlling emissions sources, linking national abatement actions efficiently with global targets, and verifying emissions after targets have been set are other important considerations that policy makers must take into account when assessing responsibility for emissions.

In the following analysis, five approaches for assigning responsibility among countries for greenhouse gas emissions are examined. They comprise two historical and three current emissions assessments which vary by level of coverage of sources (Table 3.1):

1 cumulative CO2, energy only;
2 cumulative CO2, energy and biota (including CO2 from both fuels and land clearance);
3 CO2, energy only (current);
4 partial CH4 and CO2 (including current emissions of CO2 from energy consumption and deforestation, and methane from energy production and landfills);
5 comprehensive (current emissions of CO2, CO, CH4 and N2O from energy, industrial, biotic and agricultural sources).

Table 3.1 Sources included in selected cumulative (1860-1986) and current (1988) emissions

1 Cumulative CO2, energy only X      
2 Cumulative CO2, energy & biotab X X    
3 COT, energy (current) X      
4 Partial CH4 and CO2 (current) X' X X  
5 Comprehensive (current) X X X X

a 'Other' includes cement production, and agricultural sources, including livestock, rice cultivation, fertilizer consumption, and biomass burning apart from deforestation. The gases include CO2, CH4, CO, and N2O.
b Includes estimated net CO2 release from soil carbon and from above-ground biomass in areas converted from forests to agricultural uses only.
c CO2 and CH4 emissions.

All of the approaches have already entered discussions, either in a political or an academic context. Most of the approximately two dozen countries that have pledged thus far to meet specific national targets to stabilize or control greenhouse gas emissions have focussed on the control of CO2 emissions from energy consumption. Setting targets for CH4 (methane) from energy and industrial sources and CO2 from biotic sources, in addition to CO2 from fossil fuel combustion is being seriously explored by several industrialized countries. The Framework Convention on Climate Change signed at Rio de Janeiro in June 1992, which requires developed country Parties to submit plans for stabilizing emissions, can be interpreted to apply to all greenhouse gas sources with the exception of halocarbons controlled by the Montreal Protocol. Allocating future emissions based on historical release of greenhouse gases has been proposed by a number of researchers (Krause et al. 1989; Smith 1991; Gruebler and Fuji 1991).

Any of these source categories could form a broad basis for resource transfers from North to South to fund technology transfers or greenhouse gas abatement projects. But as the baseline against which national targets or the allocation of traceable emissions permits are set, the national inventories must be accurate and verifiable. A consensus is more likely to be reached over setting targets for sources and gases that can be measured with confidence. Although in the past, regional environmental agreements have been signed before baseline national emissions estimates were completed, in the case of greenhouse gas emissions where the differences in countries' emissions rates are so great, nations are unlikely to favour setting specific targets for controlling sources for which accurate baseline inventories at the country level are not yet available and cannot yet be monitored.

In the following analysis, the relative comprehensiveness of the different source categories is briefly summarized, followed by a discussion of the problems in estimating emissions from these different sources and time frames. In addition, the implications of the five emission categories is illustrated for a selection of the major emitting countries. A brief description of the emissions totals used, and the method for calculating national inventories appear in Appendix A and Appendix B.