In Kyoto, countries agreed to reduce their anthropogenic greenhouse-gas (GHG) emissions by 8 % in 2008–2012, relative to (for most GHG's) the emissions in 1990. The Netherlands committed itself to reductions of 6 %. For the period after that, the required emission reductions will more likely be on the order of 30 % or more, on which the negotiations will start soon. Such reductions require wide-spread measures in all economic sectors with often only small incremental contributions. The achieved reductions will be reported following standard IPCC-Guidelines. Basically, this is a bottom-up summation over various (anthropogenic) activities of the products of the volume of that activity and an emission factor. As reductions become more and more challenging to achieve, and as penalties for non-compliance may become more serious, the need for independent verification mechanisms — at country level at first, later perhaps at smaller administrative units — will increase.

Eventually, emission reductions should have observable effects on atmospheric concentrations of GHGs. These concentrations should be the basis of an independent, top-down approach to verify the emission reductions. Inverse methods provide such an approach. Atmospheric concentrations of GHGs are determined by the net flux in and out of the atmosphere. For the three primary GHGs, CO2, CH4 and N2O, the magnitude of natural fluxes are of similar orders of magnitude as anthropogenic emissions (others like SF6, HFCs, etc. are of almost exclusively anthropogenic origin). So, an important pre-requisite for any verification methodology is that it should be able to separate the two — natural vs. anthropogenic — contributions.

Inverse methods use actually measured time series of a particular greenhouse-gas mixing-ratio at one or more sites, together with transport and diffusion information from an atmospheric model to improve the source/sink distributions of that greenhouse gas in time and space. A source/sink distribution must be provided to the inverse computation scheme that will be improved towards values more in agreement with the observed concentration fields. The method so-far has been used mostly at larger, continental to global scales (e.g., Bousquet et al. 1999a,b), but in principle can be used at smaller scales, too (Hensen et al.,1999; Dolman et al., 2004). Thus, it can provide a tool to verify the emissions at roughly national and perhaps sub-national levels.

However, the challenges of developing a verification tool at these relative small scales are large and in part of a different nature than those developed for continental to global scales. These have to do with the very large variability of fluxes in landscapes exhibiting, e.g. cities and forests, covariance of fluxes and atmospheric PBL-dynamics and the resulting problems of representativeness and aggregation of data. Therefore, at these scales, it is imperative to make use of all of the constraints provided/imposed by different data streams, and by process knowledge of ecosystem behaviour (natural and man-made) and of atmospheric dynamics as embodied in state-of-the-art models.

Based on the above situation sketch, the overall objective of the current research proposal is:

To develop an advanced GHG-information system — consisting of a comprehensive set of monitoring systems, combined with a complementary suite of 3D-models — that is able to quantify the magnitude, trends and associated uncertainties of the biogenic and anthropogenic greenhouse-gas budgets high spatial and temporal resolutions. While doing so, we will develop a protocol to provide an independent reference estimate for the verification of national emissions reported by the parties in the UNFCCC and Kyoto framework.

A lot of research addressing the above issues at the regional scale is of relative recent origin, and large efforts are currently being made by U.S. and European consortia. Dutch participation, by partners also contributing to the present proposal, in European frameworks has been and still is highly significant and visible. The present proposal aims to continue this situation by providing on one hand the individual partners the possibility to continue playing this role in their respective niches, while — by providing an integrated framework and end-target — on the other hand we will enable the consortium as a whole to make definite steps towards actually reaching GHG-budget closure at regional scales. The latter objective, which is of high international scientific and political relevance, can never be realized from individual grants alone, and as such, only the CcSP-grant may provide a sufficient level of thrust to achieve the ambitious goals of this proposal.

A complete PDF-version of the project proposal (excl. Work Package Six) can be downloaded here.

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