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 CO2 seasonal cycles. 2018 has a good coverage of European regions affected by drought, allowing the investigation of how ecosystem flux anomalies impacted spatial CO2 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 CO2 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 CO2 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 CO2 transition phases before and after July were slower in 2018 compared to 2017, suggesting an extension of the growing season, with either continued CO2 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 CO2 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 CO2 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'.

Agenzia Nazionale per le Nuove Tecnologie l'Energia e lo Sviluppo Economico Sostenibile Rome Italy

AGH University of Science and Technology 30059 Krakow Poland

Aix Marseille Univ Avignon Université CNRS IRD Institut Méditerranéen de Biodiversité et d'Ecologie marine et continentale Marseille France

Atmospheric Chemistry Research Group School of Chemistry University of Bristol Bristol UK

Centre for Environmental and Climate Research Lund University Lund Sweden

Centre for Isotope Research University of Groningen Nijenborgh 6 9747 AG Groningen The Netherlands

Climate and Health Programme Barcelona Spain

Department of Geography Ludwig Maximilians University 80333 Munich Germany

Department of Physical Geography and Ecosystem Science Lund University Lund Sweden

Deutscher Wetterdienst Hohenpeißenberg Meteorological Observatory Hohenpeißenberg Germany

DRD OPE Andra Bure France

Empa Swiss Federal Laboratories for Materials Science and Technology Duebendorf Switzerland

Environmental Chemical Processes Laboratory University of Crete Greece

Environmental Protection Agency Dublin Ireland

European Commission Joint Research Centre Ispra Italy

Finnish Meteorological Institute Helsinki Finland

Global Change Research Institute of the Czech Academy of Sciences Brno Czech Republic

ICOS ERIC Carbon Portal Lund Sweden

Institució Catalana de Recerca i Estudis Avancats Barcelona Spain

Institut de Ciencia i Tecnologia Ambientals Universitat Autonoma de Barcelona Barcelona Spain

Institute for Atmospheric and Earth System Research University of Helsinki Helsinki Finland

Institute for Atmospheric and Environmental Sciences Goethe University Frankfurt Frankfurt am Main Germany

Italian Air Force Meteorological Service Rome Italy

Izana Atmospheric Research Center Meteorological State Agency of Spain Tenerife Spain

Laboratoire d'Aérologie UPS Université Toulouse 3 CNRS Toulouse France

Max Planck Institute for Biogeochemistry Jena Germany

National Centre for Atmospheric Science University of East Anglia Norwich UK

National Research Council Institute of Atmospheric Sciences and Climate Bologna Italy

National University of Ireland Galway Galway Ireland

Netherlands Organisation for Applied Scientific Research Petten The Netherlands

NILU Norwegian Institute for Air Research Oslo Norway

Research Centre for Astronomy and Earth Sciences Sopron Hungary

Ricerca sul Sistema Energetico Milan Italy

Royal Belgian Institute for Space Aeronomy Brussels Belgium

Swedish University of Agricultural Sciences Unit for Field based Forest Research 92291 Vindeln Sweden

Umweltbundesamt Berlin Germany

Université Clermont Auvergne CNRS Laboratoire de Météorologie Physique UMR 6016 Clermont Ferrand France

Université Paris Saclay CEA CNRS UVSQ Laboratoire des Sciences du Climat et de l'Environnement Gif sur Yvette France

University of Bern Physics Institute Climate and Environmental Physics Division and Oeschger Center for Climate Change Research Bern Switzerland

University of Eastern Finland Kuopio Finland

University of Heidelberg Institut fuer Umweltphysik Heidelberg Germany

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Ramonet M, et al. 2010. A recent build-up of atmospheric CO2 over Europe. Part 1: observed signals and possible explanations. Tellus B 62, 1–13. (10.1111/j.1600-0889.2009.00442.x) DOI

Conway TJ, Tans PP. 1999. Development of the CO2 latitude gradient in recent decades. Global Biogeochem. Cycles 13, 821 (10.1029/1999GB900045) DOI

Dlugokencky EJ, et al. 2009. Observational constraints on recent increases in the atmospheric CH4 burden. Geophys. Res. Lett. 36, L18803 (10.1029/2009gl039780) DOI

Miller JB, Gatti LV, d'Amelio MTS, Crotwell AM, Dlugokencky EJ, Bakwin P, Artaxo P, Tans PP. 2007. Airborne measurements indicate large methane emissions from the eastern Amazon basin. Geophys. Res. Lett. 34, L10809 (10.1029/2006gl029213) DOI

Ciais P, Rayner P, Chevallier F, Bousquet P, Logan M, Peylin P, Ramonet M. 2010. Atmospheric inversions for estimating CO2 fluxes: methods and perspectives. Clim. Change 103, 69–92. (10.1007/s10584-010-9909-3) DOI

Bergamaschi P, et al. 2015. Top-down estimates of European CH4 and N2O emissions based on four different inverse models. Atmos. Chem. Phys. 15, 715–736. (10.5194/acp-15-715-2015) DOI

Chevallier F, Remaud M, O'Dell CW, Baker D, Peylin P, Cozic A. 2019. Objective evaluation of surface- and satellite-driven CO2 atmospheric inversions. Atmos. Chem. Phys. Discuss. 2019, 1–28. (10.5194/acp-2019-213) DOI

Kountouris P, Gerbig C, Rödenbeck C, Karstens U, Koch TF, Heimann M. 2018. Atmospheric CO2 inversions on the mesoscale using data-driven prior uncertainties: quantification of the European terrestrial CO2 fluxes. Atmos. Chem. Phys. 18, 3047–3064. (10.5194/acp-18-3047-2018) DOI

Gurney KR, et al. 2003. TransCom 3 CO2 inversion intercomparison: 1. Annual mean control results and sensitivity to transport and prior flux information. Tellus Ser. B Chem. Phys. Meteorol. 55, 555–579. (10.3402/tellusb.v55i2.16728) DOI

Broquet G, et al. 2013. Regional inversion of CO2 ecosystem fluxes from atmospheric measurements: reliability of the uncertainty estimates. Atmos. Chem. Phys. 13, 9039–9056. (10.5194/acp-13-9039-2013) DOI

Berchet A, Pison I, Chevallier F, Bousquet P, Bonne JL, Paris JD. 2015. Objectified quantification of uncertainties in Bayesian atmospheric inversions. Geosci. Model Dev. 8, 1525–1546. (10.5194/gmd-8-1525-2015) DOI

Bastos A, et al. 2020. Impacts of extreme summers on European ecosystems: a comparative analysis of 2003, 2010 and 2018. Phil. Trans. R. Soc. B 375, 20190507 (10.1098/rstb.2019.0507) PubMed DOI PMC

Rödenbeck C, Zaehle S, Keeling R, Heimann M. 2020. The European carbon cycle response to heat and drought as seen from atmospheric CO2 data for 1999–2018. Phil. Trans. R. Soc. B 375, 20190506 (10.1098/rstb.2019.0506) PubMed DOI PMC

Smith NE, et al. 2020. Spring enhancement and summer reduction in carbon uptake during the 2018 drought in northwestern Europe. Phil. Trans. R. Soc. B 375, 20190509 (10.1098/rstb.2019.0509) PubMed DOI PMC

Thompson RL, et al. 2020. Changes in net ecosystem exchange over Europe during the 2018 drought based on atmospheric observations. Phil. Trans. R. Soc. B 375, 20190512 (10.1098/rstb.2019.0512) PubMed DOI PMC

WMO-GAW. 2012. 16th WMO/IAEA meeting on carbon dioxide, other greenhouse gases and related tracers measurement techniques (GGMT-2011), Wellington, New Zealand (ed. G Brailsford). Geneva, Switzerland: WMO.

Zhao CL, Tans PP. 2006. Estimating uncertainty of the WMO mole fraction scale for carbon dioxide in air. J. Geophys. Res. Atmos. 111, D08S09 (10.1029/2005JD006003) DOI

Cooperative Global Atmospheric Data Integration Project. 2018. Multi-laboratory compilation of atmospheric carbon dioxide data for the period 1957–2017; obspack_co2_1_GLOBALVIEWplus_v4.1_2018-10-29 [data set]. Boulder, CO: NOAA Earth System Research Laboratory, Global Monitoring Division.

Artuso F, Chamard P, Piacentino S, Sferlazzo DM, De Silvestri L, di Sarra A, Meloni D, Monteleone F. 2009. Influence of transport and trends in atmospheric CO2 at Lampedusa. Atmos. Environ. 43, 3044–3051. (10.1016/j.atmosenv.2009.03.027) DOI

Hazan L, Tarniewicz J, Ramonet M, Laurent O, Abbaris A. 2016. Automatic processing of atmospheric CO2 and CH4 mole fractions at the ICOS Atmosphere Thematic Centre. Atmos. Meas. Tech. 9, 4719–4736. (10.5194/amt-9-4719-2016) DOI

Kwok CY, et al. 2015. Comprehensive laboratory and field testing of cavity ring-down spectroscopy analyzers measuring H2O, CO2, CH4 and CO. Atmos. Meas. Tech. 8, 3867–3892. (10.5194/amt-8-3867-2015) DOI

Tans PP, Crotwell AM, Thoning KW. 2017. Abundances of isotopologues and calibration of CO2 greenhouse gas measurements. Atmos. Meas. Tech. 10, 2669–2685. (10.5194/amt-10-2669-2017) DOI

Copernicus Climate Change Service (C3S). 2017. ERA5: Fifth generation of ECMWF atmospheric reanalyses of the global climate Copernicus Climate Change Service Climate Data Store (CDS). See https://cds.climate.copernicus.eu/cdsapp#!/home.

Biraud S, Ciais P, Ramonet M, Simmonds P, Kazan V, Monfray P, O'Doherty S, Spain TG, Jennings SG. 2000. European greenhouse gas emissions estimated from continuous atmospheric measurements and radon 222 at Mace Head. Ireland . J. Geophys. Res. Atmos. 105, 1351–1366. (10.1029/1999JD900821) DOI

Geels C, et al. 2007. Comparing atmospheric transport models for future regional inversions over Europe – Part 1: mapping the atmospheric CO signals. Atmos. Chem. Phys. 7, 3461–3479. (10.5194/acp-7-3461-2007) DOI

Gerbig C, Körner S, Lin JC. 2008. Vertical mixing in atmospheric tracer transport models: error characterization and propagation. Atmos. Chem. Phys. 8, 591–602. (10.5194/acp-8-591-2008) DOI

Thoning KW, Tans PP, Komhyr WD. 1989. Atmospheric carbon dioxide at Mauna Loa Observatory, 2, analysis of the NOAA GMCC data, 1974, 1985. J. Geophys. Res. 94, 8549–8565. (10.1029/JD094iD06p08549) DOI

Stanley KM, et al. 2018. Greenhouse gas measurements from a UK network of tall towers: technical description and first results. Atmos. Meas. Tech. 11, 1437–1458. (10.5194/acp-2018-839) DOI

Conil S, Helle J, Langrene L, Laurent O, Ramonet M. 2019. Continuous atmospheric CO2, CH4 and CO measurements at the OPE station in France from 2011 to 2018. Atmos. Meas. Tech. 12, 6361–6383. (10.5194/amt-12-6361-2019) DOI

Pal S, Lopez M, Schmidt M, Ramonet M, Gibert F, Xueref-Remy I, Ciais P. 2015. Investigation of the atmospheric boundary layer depth variability and its impact on the Rn-222 concentration at a rural site in France. J. Geophys. Res. Atmos. 120, 623–643. (10.1002/2014jd022322) DOI

Koffi EN, et al. 2016. Evaluation of the boundary layer dynamics of the TM5 model over Europe. Geosci. Model Dev. 9, 3137–3160. (10.5194/gmd-9-3137-2016) DOI

Aulagnier C, Rayner P, Ciais P, Ramonet M, Rivier L, Vautard R. 2010. Is the recent build-up of atmospheric CO2 over Europe reproduced by models: an overview with the atmospheric mesoscale transport model CHIMERE. Tellus B 62, 14–25. (10.1111/j.1600-0889.2009.00443) DOI

Karstens U, Gloor M, Heimann M, Rodenbeck C. 2006. Insights from simulations with high-resolution transport and process models on sampling of the atmosphere for constraining midlatitude land carbon sinks. J. Geophys. Res. 111, D12301 (10.1029/2005JD006278) DOI

Patra PK, et al. 2008. TransCom model simulations of hourly atmospheric CO2: analysis of synoptic-scale variations for the period 2002–2003. Global Biogeochem. Cycles 22, GB4013 (10.1029/2007GB003081) DOI

Bakwin PS, Tans PP, Hurst DF, Zhao C. 1998. Measurements of carbon dioxide on very tall towers: results of the NOAA/CMDL program. Tellus 50B, 401–415. (10.3402/tellusb.v50i5.16216) DOI

Buras A, Rammig A, Zang CS. 2020. Quantifying impacts of the drought 2018 on European ecosystems in comparison to 2003. Biogeosciences 17, 1655–1672. (10.5194/bg-17-1655-2020) DOI

Copernicus. 2019. European state of the climate 2018. Reading, UK: ECMRWF.

Vogel MM, Zscheischler J, Wartenburger R, Dee D, Seneviratne SI. 2019. Concurrent 2018 hot extremes across Northern Hemisphere due to human-induced climate change. Earth's Future 7, 692–703. (10.1029/2019ef001189) PubMed DOI PMC

Reinermann S, Gessner U, Asam S, Kuenzer C, Dech S. 2019. The effect of droughts on vegetation condition in Germany: an analysis based on two decades of satellite earth observation time series and crop yield statistics. Remote Sensing 11, 1783 (10.3390/rs11151783) DOI

Peters GP, Andrew RM, Canadell JG, Friedlingstein P, Jackson RB, Korsbakken JI, Quéré CL, Peregon A. 2019. Carbon dioxide emissions continue to grow amidst slowly emerging climate policies. Nat. Clim. Change 10, 3–6. (10.1038/s41558-019-0659-6) DOI

Friedlingstein P, et al. 2019. Global carbon budget 2019. Earth Syst. Sci. Data 11, 1783–1838. (10.5194/essd-11-1783-2019) DOI

Yiou P, Nogaj M. 2004. Extreme climatic events and weather regimes over the North Atlantic: when and where? Geophys. Res. Lett. 31, L07202 (10.1029/2003gl019119) DOI

Hertig E, Jacobeit J. 2014. Variability of weather regimes in the North Atlantic-European area: past and future. Atmos. Sci. Let. 15, 314–320. (10.1002/asl2.505) DOI

Alvarez-Castro MC, Faranda D, Yiou P. 2018. Atmospheric dynamics leading to west European summer hot temperatures since 1851. Complexity 2018, 10 (10.1155/2018/2494509) DOI

van der Wiel K, Bloomfield HC, Lee RW, Stoop LP, Blackport R, Screen JA, Selten FM. 2019. The influence of weather regimes on European renewable energy production and demand. Environ. Res. Lett. 14, 094010 (10.1088/1748-9326/ab38d3) DOI

Kivi R, Heikkine P. 2016. Fourier transform spectrometer measurements of column CO2 at Sodankylä, Finland. Geosci. Instrum. Method. Data Syst. 5, 271–279. (10.5194/gi-5-271-2016) DOI

Sha MK, et al. 2019. Intercomparison of low and high resolution infrared spectrometers for ground-based solar remote sensing measurements of total column concentrations of CO2, CH4 and CO. Atmos. Meas. Tech. Discuss. 2019, 1–67. (10.5194/amt-2019-371) DOI

Ciais P, et al. 2005. Europe-wide reduction in primary productivity caused by the heat and drought in 2003. Nature 437, 529–533. (10.1038/nature03972) PubMed DOI

Lian X, et al. 2020. Summer soil drying exacerbated by earlier spring greening of northern vegetation. Sci. Adv. 6, eaax0255 (10.1126/sciadv.aax0255) PubMed DOI PMC

Hakkarainen J, Ialongo I, Maksyutov S, Crisp D. 2019. Analysis of four years of global XCO2 anomalies as seen by orbiting carbon observatory-2. Remote Sensing 11, 850 (10.3390/rs11070850) DOI

Connor B, et al. 2016. Quantification of uncertainties in OCO-2 measurements of XCO2: simulations and linear error analysis. Atmos. Meas. Tech. 9, 5227–5238. (10.5194/amt-9-5227-2016) DOI

Long-term daily hydrometeorological drought indices, soil moisture, and evapotranspiration for ICOS sites

The 2018 European heatwave led to stem dehydration but not to consistent growth reductions in forests

Altered energy partitioning across terrestrial ecosystems in the European drought year 2018

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