Servizio Comunitario di Informazione in materia di Ricerca e Sviluppo - CORDIS

D5.3 Report on the estimation of the contemporary land carbon sink and its causes

The Kyoto Protocol to the United Nations Framework Convention on Climate Change (UNFCCC) allows parties to count forestry and other land-use carbon sinks within their accounted emissions of carbon dioxide (CO2).

CAMELS (Carbon Assimilation and Modelling of the European Land Surface) provides scientific advice to support this, by quantifying the contribution of European ecosystems and land use to changes in atmospheric CO2. For the first time, data from a variety of sources were brought together with state-of-the-art models to give a complete picture of the exchange of carbon between the atmosphere and the European land surface.

Computer models based on mathematical equations can be used to estimate processes of carbon exchange at every point across Europe, but these models cannot be perfect and their results are always therefore uncertain to some extent. By compiling extensive information from the forestry sector from nations across Europe, we have mapped the biomass of European forests and established that past afforestation of agricultural lands has caused a net accumulation of carbon in the The Fraction of Absorbed Photosynthetically Active Radiation (FAPAR) FAPAR is derived from remote sensing data which enables assessment and monitoring of land surfaces around the globe.

The eddy covariance technique is used to measure the net CO2 exchange between ecosystems and atmosphere. In Europe there are now more than 100 eddy covariance sites covering different land uses and climate conditions with 10 years of measurements. CAMELS initiated a standardization work to check the quality of the eddy covariance datasets. The results from CAMELS were included in the Carboeurope Integrated Project database.

Using eddy-covariance data from all major plant types indicates how well the models represent natural vegetation. The optimised parameter values can then be used as a priori values in the global Carbon Cycle Data Assimilation System (CCDAS) described later in this report. The ORCHIDEE model was used to simulate changes in the growing season and the portion of the year in which the ecosystems. The MOSES model (Met Office Surface Exchange Scheme) was used to simulate the sinks and sources of carbon over the global land surface. Taking observed and reconstructed changes in climate, CO2 concentrations and land use as inputs, MOSES simulated biological processes in the vegetation across the different continents and produced estimates of local uptake and release of carbon in response to the imposed environmental changes.

Thus CCDAS combines a top-down and bottom up approach. CCDAS has been developed by the CCDAS consortium, which consists of CAMELS participants plus external partners (see The first output of CCDAS using 20 years of atmospheric CO2 observations obtains a considerable reduction in uncertainty for about 10-15 parameters that enter the optimisation. CO2 fluxes derived with the optimised BETHY show a clear relation to the El Nino-Southern Oscillation (ENSO) cycle, except for the time after the Pinatubo eruption. During El Nino (warm) conditions in the east Pacific, large parts of the tropical ecosystem come under water stress with reduced photosynthesis.
The spatial distribution of the long-term mean net flux of CO2 shows a relatively large uptake over the northern hemisphere continents, and uptake over the tropical continents, which partly balances the large background source from land use change.

Project website:
Forest inventory data:
FAPAR from remote sensing:
CO2 fluxes from eddy-covariance measurements:
Carbon Cycle Data Assimilation System:

Reported by

Via S. Camillo de Lellis
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