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Research article - Peer-reviewed, 2020

The fingerprint of the summer 2018 drought in Europe on ground-based atmospheric CO(2)measurements

Ramonet, M.; Ciais, P.; Apadula, F.; Bartyzel, J.; Bastos, A.; Bergamaschi, P.; Blanc, P. E.; Brunner, D.; di Torchiarolo, L. Caracciolo; Calzolari, F.; Chen, H.; Chmura, L.; Colomb, A.; Conil, S.; Cristofanelli, P.; Cuevas, E.; Curcoll, R.; Delmotte, M.; di Sarra, A.; Emmenegger, L.;
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During the summer of 2018, a widespread drought developed over Northern and Central Europe. The increase in temperature and the reduction of soil moisture have influenced carbon dioxide (CO2) exchange between the atmosphere and terrestrial ecosystems in various ways, such as a reduction of photosynthesis, changes in ecosystem respiration, or allowing more frequent fires. In this study, we characterize the resulting perturbation of the atmospheric CO(2)seasonal cycles. 2018 has a good coverage of European regions affected by drought, allowing the investigation of how ecosystem flux anomalies impacted spatial CO(2)gradients between stations. This density of stations is unprecedented compared to previous drought events in 2003 and 2015, particularly thanks to the deployment of the Integrated Carbon Observation System (ICOS) network of atmospheric greenhouse gas monitoring stations in recent years. Seasonal CO(2)cycles from 48 European stations were available for 2017 and 2018. Earlier data were retrieved for comparison from international databases or national networks. Here, we show that the usual summer minimum in CO(2)due to the surface carbon uptake was reduced by 1.4 ppm in 2018 for the 10 stations located in the area most affected by the temperature anomaly, mostly in Northern Europe. Notwithstanding, the CO(2)transition phases before and after July were slower in 2018 compared to 2017, suggesting an extension of the growing season, with either continued CO(2)uptake by photosynthesis and/or a reduction in respiration driven by the depletion of substrate for respiration inherited from the previous months due to the drought. For stations with sufficiently long time series, the CO(2)anomaly observed in 2018 was compared to previous European droughts in 2003 and 2015. Considering the areas most affected by the temperature anomalies, we found a higher CO(2)anomaly in 2003 (+3 ppm averaged over 4 sites), and a smaller anomaly in 2015 (+1 ppm averaged over 11 sites) compared to 2018. This article is part of the theme issue 'Impacts of the 2018 severe drought and heatwave in Europe: from site to continental scale'.


atmospheric CO(2)measurements; net ecosystem exchange; drought; ICOS

Published in

Philosophical Transactions B: Biological Sciences
2020, volume: 375, number: 1810, article number: 20190513
Publisher: ROYAL SOC

Authors' information

Ramonet, M.
Universite Paris Saclay
Ciais, P.
Universite Paris Saclay
Apadula, F.
Ric Sul Sistema Energet
Bartyzel, J.
AGH University of Science and Technology
Bastos, A.
University of Munich
Bergamaschi, P.
European Commission Joint Research Centre
Blanc, P. E.
Institut de Recherche pour le Developpement (IRD)
Brunner, D.
Swiss Federal Laboratories for Materials Science and Technology (EMPA)
di Torchiarolo, L. Caracciolo
Italian Air Force Meteorol Serv
Calzolari, F.
Consiglio Nazionale delle Ricerche (CNR)
Chen, H.
University of Groningen
Chmura, L.
AGH University of Science and Technology
Colomb, A.
Universite Clermont Auvergne (UCA)
Conil, S.
Cristofanelli, P.
Consiglio Nazionale delle Ricerche (CNR)
Cuevas, E.
Max Planck Institute for Biogeochemistry
Curcoll, R.
Autonomous University of Barcelona
Delmotte, M.
Universite Paris Saclay
di Sarra, A.
Italian National Agency New Technical Energy and Sustainable Economics Development
Emmenegger, L.
Swiss Federal Laboratories for Materials Science and Technology (EMPA)
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Sustainable Development Goals

SDG13 Climate action

UKÄ Subject classification

Climate Research
Environmental Sciences

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