Lay summary

CarboCount CH will investigate human-related emissions and natural exchange between atmosphere and biosphere of the two most important long-lived greenhouse gases carbon dioxide (CO2) and methane (CH4) in Europe and especially in Switzerland. As one of the signatory nations of the Kyoto Protocol, Switzerland is obliged to report to the protocol and urge the reduction of its man-made greenhouse gas emissions including CO2 and CH4.

CO2, which is emitted in vast amounts through the burning of fossil fuels, is partially absorbed by oceans and partially by the biosphere which uses CO2 for the production of biomass via photosynthesis. Atmospheric CO2 levels are therefore increasing only about half as rapidly as they would if all emitted CO2 remained in the atmosphere. It is highly uncertain, however, how the storage capacity of oceans and biosphere will evolve in the future under a changing climate. CH4 is also emitted from a variety of both anthropogenic and natural sources and future levels of CH4 are similarly difficult to predict as those of CO2.

The project CarboCount CH will improve our understanding of biosphere-atmosphere exchange processes in a regional environment typical of the northern mid-latitudes. In addition, CarboCount CH will provide quantitative estimates of CO2 and CH4 fluxes in Switzerland through a unique combination of information from observations and models. These estimates will provide invaluable input to Swiss policy makers in the context of climate change, particularly for the ongoing post-Kyoto negotiations.

To achieve its goals, CarboCount CH will setup a network of four new atmospheric CO2 and CH4 measurement sites which will complement existing networks such as the CO2 flux network Swiss Fluxnet. The retired Beromünster radio tower will be the flagship of this network where CO2 and CH4 will be measured at several different altitudes above ground providing crucial data for flux estimation. The project will also explore new avenues in modeling: The COSMO weather forecast model of MeteoSwiss will be extended with new modules to simulate transport of CO2 and CH4 in the atmosphere and to describe the exchange of CO2 between atmosphere and biosphere. Observations and model simulations will finally be combined in a so-called inverse modeling framework for a better quantification of greenhouse gas fluxes and emissions in Switzerland.