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Abstract

Here we estimate the biospheric carbon dioxide balance of Hungary using the adapted BIOME-BGC process oriented ecological system model. The model was calibrated using the Hungarian measurements of biosphere-atmosphere carbon dioxide exchange. After calibration, the model was run for the tour major land cover types such as croplands, grasslands, deciduous and coniferous forests for the period of 2002-2007. Our calculations suggest that all Hungarian ecological systems together formed a net carbon dioxide source during the time period studied. Since agricultural fields cover more than 50% of the total area of Hungary, the net carbon dioxide flux is dominated by the carbon balance of croplands. The average net release of CO₂ is 8.7 Mt per year with significant interannual variation: the highest net emission was 21.6 Mt CO₂ in 2003, while the lowest was 1.2 Mt CO₂ in 2006. Due to the model limitations, simulated CO₂ release from croplands is most likely overestimated, thus, the present results provide an upper limit for the potential range of the carbon balance of Hungary. The model results highlight the strong dependence of the biospheric carbon dioxide balance on the weather conditions. The results are compared with the carbon budget estimations previously published for Hungary as well as with those reported to the United Nations Framework Convention on Climate Change.