In our study we address the detection of uncertain GHG emission changes (also termed emission signals) under the Kyoto Protocol. The question to be probed is "how well do we need to know net emissions if we want to detect a specified emission signal after a given time?" No restrictions exist as to what concerns the net emitter. However, for data availability reasons and because of the excellent possibilityof inter-country comparisons, the Protocols Annex I countries are used as net emitters. Another restriction concerns the exclusion of emissions/removals due to land-use change and forestry (LUCF) as the reporting of their uncertainties is only soon becoming standard practice.
Our study centers on the preparatory detection of emission signals, which should have been applied prior to/in negotiating the Kyoto Protocol. Rigorous preparatory signal detection has not yet been carried out, neither prior to the negotiations of the Kyoto Protocol nor afterwards. The starting point for preparatory signal detection is that the Annex I countries under the Kyoto Protocol comply with with their emission limitation or reduction commitments.
Uncertainties are already monitored. However, monitored emissions and uncertainties are still dealt with in isolation. A connection between emission and uncertainty estimates for the purpose of an advanced country evaluation has not yet been established.
We apply four preparatory signal detection techniques. These are the Critical Relative Uncertainty (CRU) concept, the Verification Time (VT) concept, the Undershooting (Und) concept, and the Undershooting and Verification Time (Und&VT) concepts combined. All of the techniques identify an emission signal and consider the total uncertainty that underlies the countries emissions, either in the commitment year/period or in both the base year and the commitment year/period. The techniques follow a hierarchical order in terms of complexity permitting to explore their robustness. The most complex technique, the Und&VT concept, considers in addition to uncertainty (1) the dynamics of the signal itself permitting to ask for the verification time, the time when the signal is outstripping total uncertainty; (2) the risk (probability) that the countries true emissions in the commitment year/period are above (below) their true emission limitation or reduction commitments; (3) the undershooting that is needed to reduce this risk to a prescribed level; and (4) a corrected undershooting/risk that accounts for detectability, i.e., that fulfills a given commitment period or, equivalently, its maximal allowable verification time.
Our preparatory signal detection exercise exemplifies that the negotiations for the Kyoto Protocol were imprudent because they did not consider the consequences of uncertainty, i.e., (1) the risk that the countries true emissions in the commitment year/period are above their true emission limitation or reduction commitments; and (2) detectable targets.
Expecting that Annex I countries exhibit relative uncertainties in the range of 5-10 % and above rather than below, excluding emissions/removals due to LUCF, both the CRU concept and VT concept show that it is virtually impossible for most of the Annex I countries to meet the condition that their overall relative uncertainties are smaller than their CRUs or, equivalently, that their VTs are smaller than their maximal allowable verification times.
Moreover, the Und and the Und&VT concepts show that the countries committed emission limitation or reduction targets - or their Kyoto-compatible but detectable targets, respectively - require considerable undershooting if one wants to keep the risk low that the countries true emissios in the commitment year/period are above the true equivalents of these targets.
The amount by which a country undershoots its Kyoto target or its Kyoto-compatible but detectable target can be traded. Towards installing a successful trading regime, countries may want to also price the risk associated with this amount We anticipate that the evaluation of the countries emission signals in terms of risk and detectability will become reality.
The Intergovernmental Panel on Climate Change (IPCC) also suggests assessing total uncertainties. However, a connection between monitored emission and uncertainty estimates for the purpose of an advanced country evaluation, which considers the aforementioned risk as well as detectable targets, has not yet been established. The IPCC has to take up this challenge