The European land and inland water CO2, CO, CH4 and N2O balance between 2001 and 2005
Luyssaert, S. ; Abril, G. ; Andres, R. ; Bastviken, D. ; Bellassen, V. ; Bergamaschi, P. ; Bousquet, P. ; Chevallier, F. ; Ciais, P. ; Corazza, M. ; Dechow, R. ; Erb, K.H. ; Etiope, G. ; Fortems-Cheiney, A. ; Grassi, G. ; Hartmann, J. ; Jung, M. ; Lathiere, J. ; Lohila, A. ; Mayorga, E. ; Moosdorf, N. ; Njakou, D.S. ; Otto, J. ; Papale, D. ; Peters, W. ; Peylin, P. ; Raymond, P. ; Rodenbeck, C. ; Saarnio, S. ; Schulze, E.D. ; Szopa, S. ; Thompson, R. ; Verkerk, P.J. ; Vuichard, N. ; Wang, R. ; Wattenbach, M. ; Zaehle, S. - \ 2012
Biogeosciences 9 (2012)8. - ISSN 1726-4170 - p. 3357 - 3380.
north-atlantic oscillation - net ecosystem exchange - organic-carbon changes - atmospheric co2 - climate-change - nitrous-oxide - terrestrial biosphere - dioxide - fluxes - emissions
Globally, terrestrial ecosystems have absorbed about 30% of anthropogenic greenhouse gas emissions over the period 2000-2007 and inter-hemispheric gradients indicate that a significant fraction of terrestrial carbon sequestration must be north of the Equator. We present a compilation of the CO2, CO, CH4 and N2O balances of Europe following a dual constraint approach in which (1) a land-based balance derived mainly from ecosystem carbon inventories and (2) a land-based balance derived from flux measurements are compared to (3) the atmospheric data-based balance derived from inversions constrained by measurements of atmospheric GHG (greenhouse gas) concentrations. Good agreement between the GHG balances based on fluxes (1294 +/- 545 Tg C in CO2-eq yr(-1)), inventories (1299 +/- 200 Tg C in CO2-eq yr(-1)) and inversions (1210 +/- 405 Tg C in CO2-eq yr(-1)) increases our confidence that the processes underlying the European GHG budget are well understood and reasonably sampled. However, the uncertainty remains large and largely lacks formal estimates. Given that European net land to atmosphere exchanges are determined by a few dominant fluxes, the uncertainty of these key components needs to be formally estimated before efforts could be made to reduce the overall uncertainty. The net land-to-atmosphere flux is a net source for CO2, CO, CH4 and N2O, because the anthropogenic emissions by far exceed the biogenic sink strength. The dual-constraint approach confirmed that the European biogenic sink removes as much as 205 +/- 72 Tg C yr(-1) from fossil fuel burning from the atmosphere. However, This C is being sequestered in both terrestrial and inland aquatic ecosystems. If the C-cost for ecosystem management is taken into account, the net uptake of ecosystems is estimated to decrease by 45% but still indicates substantial C-sequestration. However, when the balance is extended from CO2 towards the main GHGs, C-uptake by terrestrial and aquatic ecosystems is offset by emissions of non-CO2 GHGs. As such, the European ecosystems are unlikely to contribute to mitigating the effects of climate change.
Effects of elevated CO2 and N deposition on CH4 emissions from European mires
Silvola, J. ; Saarnio, S. ; Foot, J. ; Sundh, I. ; Greenup, A. ; Heijmans, M.M.P.D. ; Ekberg, A. ; Mitchell, E.P. ; Breemen, N. van - \ 2003
Global Biogeochemical Cycles 17 (2003)2 - 1068. - ISSN 0886-6236 - p. 37 - 1-37-12.
atmospheric carbon-dioxide - methane emissions - boreal mire - raised co2 - northern peatlands - water-table - nitrogen deposition - bog vegetation - forest soils - temperature
 Methane fluxes were measured at five sites representing oligotrophic peatlands along a European transect. Five study plots were subjected to elevated CO2 concentration (560 ppm), and five plots to NH4NO3 (3 or 5 g N yr(-1)). The CH4 emissions from the control plots correlated in most cases with the soil temperatures. The depth of the water table, the pH, and the DOC, N and SO4 concentrations were only weakly correlated with the CH4 emissions. The elevated CO2 treatment gave nonsignificantly higher CH4 emissions at three sites and lower at two sites. The N treatment resulted in higher methane emissions at three sites (nonsignificant). At one site, the CH4 fluxes of the N-treatment plots were significantly lower than those of the control plots. These results were not in agreement with our hypotheses, nor with the results obtained in some earlier studies. However, the results are consistent with the results of the vegetation analyses, which showed no significant treatment effects on species relationships or biomass production.