National Greenhouse Gas Inventories: Understanding Uncertainties versus Potential for Improving Reliability

Abstract

We investigated the Austrian national greenhouse gas emission inventory to review the reliability and usability of such inventories. The overall uncertainty of the inventory (95% confidence interval) is just over 10% of total emissions, with nitrous oxide (N 2 O) from soils clearly providing the largest impact. Trend uncertainty -the difference between 2 years -is only about five percentage points, as important sources like soil N 2 O are not expected to show different behavior between the years and thus exhibit a high covariance. The result is very typical for industrialized countries -subjective decisions by individuals during uncertainty assessment are responsible for most of the discrepancies among countries. Thus, uncertainty assessment cannot help to evaluate whether emission targets have been met. Instead, a more rigid emission accounting system that allows little individual flexibility is proposed to provide harmonized evaluation uninfluenced by the respective targets. Such an accounting system may increase uncertainty in terms of greenhouse gas fluxes to the atmosphere. More importantly, however, it will decrease uncertainty in intercountry comparisons and thus allow for fair burden sharing. Setting of postKyoto emission targets will require the independent evaluation of achievements. This can partly be achieved by the validation of emission inventories and thorough uncertainty assessment.

Practical Policy Applications of Uncertainty Analysis for National Greenhouse Gas Inventories

“…In contrast, we conclude that quantitative uncertainty estimates at the national level currently do not have the necessary characteristics to be used for compliance purposes (e.g., unbiased in that they are comparable across categories and Parties). A similar conclusion was reached by Winiwarter (2007), although he did not discuss the reasons why he reached this conclusion. As in our paper, Rousse and Sévi (2007) make the critical distinction between uncertainties in emissions estimates (i.e., inventory uncertainty) and market uncertainties.…”

Integrated model for robust emission trading under uncertainties: Cost-effectiveness and environmental safety

“…Projected (baseline) country-specific emission levels in 2020 are derived from the GAINS model, and the pledge emission reduction targets in 2020 are set according to (Wagner and Amann, 2009). The data on emission uncertainties and costs of reducing uncertainties are compiled from IPCC, Nahorski et al, 2007;Obersteiner et al, 2000;Godal et al, 2003, Winiwarter andRypdal, 2001;Winiwarter, 2007;Wagner and Amann, 2009;Wagner et al, 2012. We employ uncertain emission level in the year 2020 as percentage of the reported business as usual emission level in 2020. Table 2 illustrates the results of emission permit trades among seven countries ignoring uncertainties.…”

Kapitel 2: Emissionen und Konzentrationen strahlungswirksamer atmosphärischer Spurenstoffe

“…Durch die zunehmenden Konzentrationen von N 2 O in der Stratosphäre und dessen Potential zur Ozonzerstörung könnte die Erholung jedoch gefährdet sein (Ravishankara et al, 2009) (Winiwarter und Rypdal, 2001). Weitere Publikationen zu dem Thema (Winiwarter, 2007;Winiwarter und Muik, 2010) geben Aufschluss über wesentliche Eigenheiten von solchen Analysen. Nicht nur wesentliche Ergebnisse, sondern auch die wichtigsten Fehlerquellen und Sensitivitäten können herausgelesen werden, und das nicht nur für Österreich, sondern auch im Vergleich mit einer Reihe von anderen Ländern.…”