A decisive action to fight against this phenomenon in a holistic way was the Kyoto Protocol, which has imposed a reduction of greenhouse gas (GHG) emissions on industrialised countries. In order to avoid a fraudulent management of data, the Kyoto Protocol has established that countries should report CO2 removals in a verifiable way. Moreover, it has emphasised the necessity of better understanding the carbon cycle for accurately determining the effect of its imbalance on climate change.
To achieve this, several research initiatives (e.g. CARBOAFRICA) have been carried out since the beginnings of the Kyoto Protocol in 1997. In the European framework, a first cluster of research projects (CARBOEUROPE cluster) has developed a first climate change monitoring system prototype for calculating the full carbon balance of Europe at several scales. CARBOEUROPE-IP carried this work on, and attempted to map both European carbon flux inputs and outputs. 75 partners from 17 countries were involved in this task, under the coordination of the Max-Planck-Institute for Biogeochemistry (Germany). The project lasted from 2004 to 2008 and was funded by European Commission under the Sixth Framework Programme (FP6).
The main challenge of the project consisted in establishing a flux monitoring system able to cover all of Europe as well as describing accurately small-scale variations within the continent. In order to obtain carbon fluxes at different spatial and temporal scales, data collection and modelling activities had to be integrated, and therefore two different approaches were considered. The first one being a bottom-up approach where carbon fluxes were quantified under a variety of land covers and land uses across Europe. These data were supported by ecosystem level data of carbon stock changes both in biomass and soils. The data sets were used for upscaling carbon fluxes to regional and continental scale. The second approach focussed on enlarging the existing European atmospheric sensing network to Southern and Western Europe in order to detail carbon flux data at continental scale. Additionally, a regional-scale study was conducted to analyse the complexity of carbon interactions between the land surface and the atmosphere. This study allowed a better quantification of carbon sinks from regional atmospheric observations, additionally reducing its inherent uncertainty.
Both approaches have been integrated to obtain a robust system to quantify the European carbon balance. In order to validate the integrated system, values were checked twice: firstly with the bottom-up approach (for small scales) and secondly with the top-down methodology (for large scales). This approach has improved the quantification of the carbon balance and has decreased the uncertainty associated with each source or sink value. Thanks to the project, it has been established that continental Europe is a CO2-carbon sink for 300 Tg C per year. The estimated sink has almost doubled since 2003, mainly due to additional process understanding of the carbon cycle. This carbon sink equals 20% of the fossil fuel emissions of continental Europe (geographic region between the Atlantic coast and the Ural Mountains) and 13% of the EU-25 in 2005. Nevertheless, if carbon equivalents of methane (CH4) and nitrous oxide (NO2) are included in the non-fossil fuel carbon balance, the EU25 sink is reduced by around 70% (81 Tg C per year). A large percentage of the European CO2 sink is located in eastern Europe, where large forest sinks are balanced with emissions from peat mining activities. Conversely, most of the fossil fuel emissions (80-90%) remain in the atmosphere and contribute to global warming, and vegetation doesn’t reduce this effect because of the GHG emissions of intensive agriculture. All these results highlighted the need of establishing an Integrated Carbon Observation System (ICOS) throughout Europe.
The project finished in 2008, and has provided valuable information to the scientific community, policy makers and other administrative bodies (e.g. UN-Framework Convention on Climate Change, Kyoto Protocol, and European Commission DG Environment). The technology readiness level is estimated to be 9 on the TRL scale. Furthermore, the project’s mission has continued in the framework of the GHG-EUROPE project.