1. EU Workshop on Uncertainties in GHG inventories
WG 3
Uncertainty estimation in
agriculture
5 September 2005

2. Questions Main problems/challenges faced?
Tier 2 does not necessarily reduce uncertainties
Correlations in the sector: animal numbers for 4A and 4B
Correlation of EFs for agricultural soils: correlated or not correlated?
AD uncertainties: For 4D most important contributor to AD uncertainty is area of cultivated organic soils
AD for management practices and application practices not available, but EF depend on these practices, practices are unknown in relation to IPCC defaults
Use of country-specific data resulted in higher uncertainties than IPCC default uncertainties
Coverage of IPCC default EF and default uncertainties: how to judge whether appropriate?

3. Questions
Main reasons behind differences in uncertainty estimates of different countries?
Highly different EF uncertainties even when IPCC defaults are used
Different methods to use default EF in estimation
Different ways to choose EF/default uncertainty from IPCC range
potentially different definitions or organic soils in different countries
Different sources of AD

4. Questions
Is there a need for harmonization of uncertainty estimation methods across MS? In particular for those estimates based on expert judgement?
Disaggregation of estimation is best way to reduce uncertainties
Reduce uncertainties with use of models based on measurement data, models not yet validated
Relative differences of models and studies are considered to be less uncertain
Is there need for further guidance? What kind of guidance?
Level of disaggregation/aggregation in source categories: results of uncertainty estimation changes with disaggregation (e.g. to direct and indirect emissions)
Correlations

5. Thank you for your attention