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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


The choice of emissions source category can bear upon countries' implied responsibility for emissions if an agreement is based on some form of the polluter-pays principle. The emissions categories involving the greatest uncertainties in measurement - the more comprehensive approaches - also place relatively greater emphasis on emissions from developing regions, where a high proportion of emissions from agricultural and biotic sources originate. Per capita emissions of CH4 and N2O are frequently greater in developing countries.

Cumulative CO2 emissions from fossil fuels can now be estimated with more precision than can most of the sources in the comprehensive source category. However, the uncertainty associated with estimating current emissions from biotic and agricultural sources should diminish with time whereas flaws in historical data, in particular those relevant to land use, may be immutable. CO2 from fuel combustion is the most verifiable and comprises about 65 per cent of current contribution to global warming.

The partial CH4 and CO2 category, which includes CO2 and CH4 from energy, industrial, and biotic sectors (and excludes the more difficult-to-measure agricultural activities and the minor trace gases) makes up about 80 per cent of the total warming effect from current emissions (excluding halocarbons). It would be significantly more difficult to monitor emissions from these sources than to monitor CO2 emissions from fossil fuel combustion, but for a variety of reasons, economic as well as environmental, it may be time to develop emissions assessments applied to this more inclusive, but not comprehensive, approach.