Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Article
  • Published:

Impact of warmer climate periods on flood hazard in the European Alps

Abstract

Flooding is a pervasive natural hazard—costly in both human and economic terms—and climate change will probably exacerbate risks around the world. Mountainous areas, such as the densely populated European Alps, are of particular concern as topography and atmospheric conditions can result in large and sudden floods. In addition, the Alps are experiencing a high warming rate, which is probably leading to more heavy rainfall events. Here, we compile palaeoflood records to test the still uncertain impact these climatic trends might have on flood frequency and magnitude in the European Alps. We demonstrate that a warming of 0.5–1.2 °C, whether naturally or anthropogenically forced, led to a 25–50% decrease in the frequency of large (≥10 yr return period) floods. This decreasing trend is not conclusive in records covering less than 200 years but persistent in those ranging from 200 to 9,000 years. By contrast, extreme (>100 yr) floods may increase with a similar degree of warming in certain small alpine catchments impacted by local intensification of extreme rainfall. Our results show how long, continuous palaeoflood records can be used to disentangle complex climate–flooding relationships and assist in improving risk assessment and management at a regional scale.

This is a preview of subscription content, access via your institution

Access options

Buy this article

Prices may be subject to local taxes which are calculated during checkout

Fig. 1: Spatiotemporal distribution of flood records from lake sediments available in the European Alps.
Fig. 2: Changes in large-flood occurrence from cooler to warmer climates.
Fig. 3: Trends in the occurrence of large floods during periods with warming or cooling trends.
Fig. 4: Changes in flood occurrence between the cool LIA and the warm MCA for the five records documenting flood magnitude.

Similar content being viewed by others

Data availability

The authors declare that the palaeoflood data supporting the findings of this study (Extended Data Table 1) are available in the NOAA database at the following address: https://www.ncei.noaa.gov/access/paleo-search/study/34712. The temperature data from Extended Data Table 4 are all available in the NOAA or PANGEA repositories.

References

  1. Center for Research on the Epidemiology of Disasters (UNISDR). The human cost of natural disasters: A global perspective, 58 pp. Retrieved from http://cred.be/sites/default/files/The_Human_Cost_of_Natural_Disasters_CRED.pdf (CRED, 2015)

  2. Dottori, F. et al. Increased human and economic losses from river flooding with anthropogenic warming. Nat. Clim. Change 8, 781–786 (2018).

    Article  Google Scholar 

  3. Fowler, H. J. et al. Anthropogenic intensification of short-duration rainfall extremes. Nat. Rev. Earth Environ. 2, 107–122 (2021).

    Article  Google Scholar 

  4. Auer, I. et al. HISTALP—historical instrumental climatological surface time series of the Greater Alpine Region. Int. J. Climatol. 27, 17–46 (2007).

    Article  Google Scholar 

  5. Pepin, N. et al. Elevation-dependent warming in mountain regions of the world. Nat. Clim. Change 5, 424–430 (2015).

    Article  Google Scholar 

  6. Giorgi, F. et al. Enhanced summer convective rainfall at Alpine high elevations in response to climate warming. Nat. Geosci. 9, 584–589 (2016).

    Article  Google Scholar 

  7. Ménégoz, M. et al. Contrasting seasonal changes in total and intense precipitation in the European Alps from 1903 to 2010. Hydrol. Earth Sci. Syst. 24, 5355–5377 (2020).

    Article  Google Scholar 

  8. IPCC: Summary for Policymakers. In IPCC Special Report on the Ocean and Cryosphere in a Changing Climate (eds Pörtner, H.-O. et al.) (IPCC, 2019).

  9. Kundzewicz, Z. W. et al. Differences in flood hazard projections in Europe—their causes and consequences for decision-making. Hydrol. Sci. J. 62, 1–14 (2016).

    Google Scholar 

  10. Blöschl, G. et al. Changing climate both increases and decreases European river floods. Nature 573, 108–111 (2019).

    Article  Google Scholar 

  11. Mangini, W. et al. Detection of trends in magnitude and frequency of flood peaks across Europe. Hydrol. Sci. J. 63, 493–512 (2018).

    Article  Google Scholar 

  12. Hundecha, Y., Parajka, J. & Viglione, A. Assessment of past flood changes across Europe based on flood-generating processes. Hydrol. Sci. J. 65, 1830–1847 (2020).

    Article  Google Scholar 

  13. Blöschl, G. et al. Increasing river floods: fiction or reality? WIREs Water 2, 329–344 (2015).

    Article  Google Scholar 

  14. Bertola, M., Viglione, A., Lun, D., Hall, J. & Blöschl, G. Flood trends in Europe: are changes in small and big floods different? Hydrol. Earth Syst. Sci. 24, 1805–1822 (2020).

    Article  Google Scholar 

  15. Tarasova, L. et al. Causative classification of flood events. WIREs Water 6, e1353 (2019).

    Article  Google Scholar 

  16. Wilhelm, B. et al. 1400 years of extreme precipitation patterns over the Mediterranean French Alps and possible forcing mechanisms. Quat. Res. 78, 1–12 (2012).

    Article  Google Scholar 

  17. Wirth, S. B., Glur, L., Gilli, A. & Anselmetti, F. S. Holocene flood frequency across the Central Alps—solar forcing and evidence for variations in North Atlantic atmospheric circulation. Quat. Sci. Rev. 80, 112–128 (2013).

    Article  Google Scholar 

  18. Czymzik, M. et al. Orbital and solar forcing of shifts in mid- to late Holocene flood intensity from varved sediments of pre-alpine Lake Ammersee (southern Germany). Quat. Sci. Rev. 61, 96–110 (2013).

    Article  Google Scholar 

  19. Giguet-Covex, C. et al. Frequency and intensity of high-altitude floods over the last 3.5 ka in NW European Alps. Quat. Res. 77, 12–22 (2012).

    Article  Google Scholar 

  20. Glur, L. et al. Frequent floods in the European Alps coincide with cooler periods of the past 2500 years. Sci. Rep. 3, 2770 (2013).

    Article  Google Scholar 

  21. Wilhelm, B. et al. Palaeoflood activity and climatic changes over the last 1400 years from lake sediments of the NW European Alps. J. Quat. Sci. 28, 189–199 (2013).

    Article  Google Scholar 

  22. Wilhelm, B. et al. Does global warming favour the occurrence of extreme floods in European Alps? First evidences from a NW Alps proglacial lake sediment record. Clim. Change 113, 563–581 (2012).

    Article  Google Scholar 

  23. Evin, G., Wilhelm, B. & Jenny, J. P. Flood hazard assessment of the Rhône River revisited with reconstructed discharges from lake sediments. Glob. Planet. Change 172, 114–123 (2019).

    Article  Google Scholar 

  24. Wirth, S. B. et al. Combining sedimentological, trace metal (Mn, Mo) and molecular evidence for reconstructing past water-column redox conditions: the example of meromictic Lake Cadagno (Swiss Alps). Geochim. Cosmochim. Acta 120, 220–238 (2013).

    Article  Google Scholar 

  25. Irmler, R., Daut, G. & Mäusbacher, R. A debris flow calendar derived from sediments of Lake Lago di Braies (N. Italy). Geomorphology 77, 69–78 (2006).

    Article  Google Scholar 

  26. Wilhelm, B., Vogel, H., Crouzet, C., Etienne, D. & Anselmetti, F. S. Frequency and intensity of palaeofloods at the interface of Atlantic and Mediterranean climate domains. Climate 12, 299–316 (2016).

    Google Scholar 

  27. Wilhelm, B., Vogel, H. & Anselmetti, F. S. A multi-centennial record of past floods and earthquakes in Valle d’Aosta, Mediterranean Italian Alps. Nat. Hazards Earth Syst. Sci. 17, 613–625 (2017).

    Article  Google Scholar 

  28. Wirth, S. B. et al. A 2000-year long seasonal record of floods in the southern European Alps. Geophys. Res. Lett. 40, 4025–4029 (2013).

    Article  Google Scholar 

  29. Swierczynski, T. et al. Mid- to late Holocene flood frequency changes in the northeastern Alps as recorded in varved sediments of Lake Mondsee (Upper Austria). Quarternary Sci. Rev. 80, 78–90 (2013).

    Article  Google Scholar 

  30. Amann, B., Szidat, S. & Grosjean, M. A millennial-long record of warm season precipitation and flood frequency for the North-western Alps inferred from varved lake sediments: implications for the future. Quat. Sci. Rev. 115, 89–100 (2015).

    Article  Google Scholar 

  31. Sabatier, P. et al. 6-kyr record of flood frequency and intensity in the western Mediterranean Alps—interplay of solar and temperature forcing. Quat. Sci. Rev. 170, 121–135 (2017).

    Article  Google Scholar 

  32. Wirth, S. B., Girardclos, S., Rellstab, C. & Anselmetti, F. S. The sedimentary response to a pioneer geo‐engineering project: tracking the Kander River deviation in the sediments of Lake Thun (Switzerland). Sedimentology 58, 1737–1761 (2011).

    Article  Google Scholar 

  33. Lauterbach, S. et al. DecLakes participants. A sedimentary record of Holocene surface runoff events and earthquake activity from Lake Iseo (Southern Alps, Italy). Holocene 22, 749–760 (2012).

    Article  Google Scholar 

  34. Rapuc, W. et al. Holocene-long record of flood frequency in Southern Alps (Lake Iseo, Italy) under human and climate forcing. Glob. Planet. Change 175, 160–172 (2019).

    Article  Google Scholar 

  35. Stewart, M., Grosjean, M., Kuglitsch, F. G., Nussbaumer, S. U. & von Gunten, L. Reconstructions of late Holocene palaeofloods and glacier length changes in the Upper Engadine, Switzerland (ca. 1450 BC–AD 420). Palaeogeogr. Palaeoclimatol. Palaeoecol. 311, 215–123 (2011).

    Article  Google Scholar 

  36. Bajard, M. et al. Pastoralism increased vulnerability of a subalpine catchment to flood hazard through changing soil properties. Palaeogeogr. Palaeoclimatol. Palaeoecol. 538, 109462 (2019).

    Article  Google Scholar 

  37. Fouinat, L. et al. Relationship between glacial activity and flood frequency in proglacial Lake Muzelle. Quat. Res. 87, 407–422 (2017).

    Article  Google Scholar 

  38. Wilhelm, B. et al. Interpreting historical, botanical, and geological evidence to aid preparations for future floods. WIREs Water 6, e1318 (2018).

    Google Scholar 

  39. Parajka, J. et al. Seasonal characteristics of flood regimes across the Alpine–Carpathian range. J. Hydrol. 394, 78–89 (2010).

    Article  Google Scholar 

  40. Blöschl et al. Current European flood-rich period exceptional compared with past 500 years. Nature 583, 560–566 (2020).

    Article  Google Scholar 

  41. Schurer, A. P. et al. Small influence of solar variability on climate over the past millennium. Nat. Geosci. 7, 104–108 (2014).

    Article  Google Scholar 

  42. Jones, P. D., Osborn, T. J. & Briffa, K. R. The evolution of climate over the last millennium. Science 292, 662–666 (2001).

    Article  Google Scholar 

  43. Renssen, H. et al. The spatial and temporal complexity of the Holocene thermal maximum. Nat. Geosci. 2, 411–414 (2009).

    Article  Google Scholar 

  44. Mudelsee, M. et al. No upward trends in the occurrence of extreme floods in central Europe. Nature 425, 166–169 (2003).

    Article  Google Scholar 

  45. Beniston, M. & Stoffel, M. Rain-on-snow events, floods and climate change in the Alps: events may increase with warming up to 4 °C and decrease thereafter. Sci. Total Environ. 571, 228–236 (2016).

    Article  Google Scholar 

  46. Moran-Tejeda, E., Lopez-Moreno, J. I., Stoffel, M. & Beniston, M. Rain-on-snow events in Switzerland: recent observations and projections for the 21st century. Clim. Res. 71, 111–125 (2016).

    Article  Google Scholar 

  47. Magny, M., Bégeot, C., Guiot, J. & Peyron, O. Contrasting patterns of hydrological changes in Europe in response to Holocene climate cooling phases. Quat. Sci. Rev. 22, 1589–1596 (2003).

    Article  Google Scholar 

  48. Magny, M. et al. North–south palaeohydrological contrasts in the central Mediterranean during the Holocene: tentative synthesis and working hypotheses. Climate 9, 2043–2071 (2013).

    Google Scholar 

  49. Goosse, H., Guiot, J., Mann, M. E., Dubinkina, S. & Sallaz-Damaz, Y. The medieval climate anomaly in Europe: comparison of the summer and annual mean signals in two reconstructions and in simulations with data assimilation. Glob. Planet. Change 84-85, 35–47 (2012).

    Article  Google Scholar 

  50. Yin, J. H. A consistent poleward shift of the storm tracks in simulations of 21st century climate. Geophys. Res. Lett. 32, L18701 (2005).

    Article  Google Scholar 

  51. Shi, X. & Durran, D. The response of orographic precipitation over idealized midlatitude mountains due to global increases in CO2. J. Climatol. 27, 3938–3956 (2014).

    Article  Google Scholar 

  52. Bengtsson, L. & Hodges, K. I. Storm tracks and climate change. J. Clim. 19, 3518–3543 (2006).

    Article  Google Scholar 

  53. Raible, C. C., Yoshimori, M., Stocker, T. F. & Casty, C. Extreme midlatitude cyclones and their implications for precipitation and wind speed extremes in simulations of the Maunder Minimum versus present day conditions. Clim. Dyn. 28, 409–423 (2007).

    Article  Google Scholar 

  54. St. George, S., Hefner, A. M. & Avila, J. Paleofloods stage a comeback. Nat. Geosci. 13, 766–768 (2020).

    Article  Google Scholar 

  55. Harrison, S. P. et al. Evaluation of CMIP5 palaeo-simulations to improve climate projections. Nat. Clim. Change 5, 735–743 (2015).

    Article  Google Scholar 

  56. Jenny, J. P. et al. A 4D sedimentological approach to reconstructing the flood frequency and intensity of the Rhône River (Lake Bourget, NW European Alps). J. Paleolimnol. 51, 469–483 (2014).

    Article  Google Scholar 

  57. Reimer, P. J. et al. IntCal13 and Marine13 radiocarbon age calibration curves 0–50,000 years cal BP. Radiocarbon 55, 1869–1887 (2013).

    Article  Google Scholar 

  58. Blaauw, M. Methods and code for ‘classical’ age-modelling of radiocarbon sequences. Quat. Geochronol. 5, 512e518 (2010).

    Article  Google Scholar 

  59. R Development Core Team R: a Language and Environment for Statistical Computing (R Foundation for Statistical Computing, 2011); http://www.R-project.org/

  60. Arnaud, F. et al. Erosion under climate and human pressures: an alpine lake sediment perspective. Quat. Sci. Rev. 152, 1–18 (2016).

    Article  Google Scholar 

  61. Affolter, S. et al. Central Europe temperature constrained by speleothem fluid inclusion water isotopes over the past 14,000 years. Sci. Adv. 5, eeav3809 (2019).

    Article  Google Scholar 

  62. Masson-Delmotte, V. et al. in Climate Change 2013: The Physical Science Basis (eds Stocker, T. F. et al.) Ch. 5 (Cambridge Univ. Press, 2013).

  63. Holzhauser, H., Magny, M. & Zumbühl, H. J. Glacier and lake-level variations in west-central Europe over the last 3500 years. Holocene 15, 789–801 (2005).

    Article  Google Scholar 

  64. Newcombe, R. G. Interval estimation for the difference between independent proportions: comparison of eleven methods. Stat. Med. 17, 873–890 (1998).

    Article  Google Scholar 

  65. Hamed, K. H. & Ramachandra, R. A modified Mann–Kendall trend test for autocorrelated data. J. Hydrol. 204, 182–196 (1998).

    Article  Google Scholar 

Download references

Acknowledgements

The data collection and the study design have been facilitated by the PAGES Floods Working Group that fosters collaborations. Sediment coring on Lake Bourget was performed using the French national sediment coring facility C2FN, in the framework of the excellence equipment project Equipe CLIMCOR (11-EQPX-0009, W.R., F.A., P.S. and B.W.) funded by the French National Agency for Research, ANR. The study of Lake Bourget sediment cores was performed in the framework of the CRIT-LAKES project funded by the Université Savoie Mont Blanc and the national CNRS programme EC2CO BIOHEFECT. The data analysis was performed in R using the supporting package trend. The authors acknowledge comments on preliminary publication versions from J.D. Creutin, G. Durand, C. Obled and M. Ménégoz as well as further colleagues for informal discussion during our Friday’s beer.

Author information

Authors and Affiliations

Authors

Contributions

All authors designed the study and B.W. wrote the first draft of the paper. B.W. collated the database with the help of B.A., W.R., M.C., C.G.-C., L.G., R.I., P.S., T.S. and S.B.W. W.R. conducted the sedimentological and geochronological analyses of the Lake Bourget sequence. B.W., M.N. and J.B. conducted the statistical analyses. All authors contributed to interpreting the results. All authors contributed to framing and revising the paper.

Corresponding author

Correspondence to B. Wilhelm.

Ethics declarations

Competing interests

The authors declare no competing interests.

Peer review

Peer review information

Nature Geoscience thanks Samuel Munoz and the other, anonymous, reviewer(s) for their contribution to the peer review of this work. Primary Handling Editor: James Super.

Additional information

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Extended data

Extended Data Fig. 1 Data acquired to extend the 350-year paleoflood record of the Rhône River to the the last millennium.

Data acquired to extend the 350-year paleoflood record of the Rhône River to the the last millennium. The method used is identical to Jenny et al. (2014)56. (A) Bathymetry of Lake Bourget and coring sites from Jenny et al. (2014)56 and from the 2017 campaign (this study). (B) Stratigraphical correlation of the two core datasets along transect A and B, with indications of historical flood dates56 and radiocarbon samples (Extended Data Table 4). (C) Age-depth model based on historical flood events and radiocarbon ages, using the software-package ‘clam’58.

Extended Data Fig. 2 Evaluation of the newly reconstructed Lake Bourget palaeoflood record.

Evaluation of the newly reconstructed Lake Bourget palaeoflood record over the last 350 years (a) and the last two millennia (b). Over the last 350 years, the new record (b.) is compared to the record from Evin et al. (2019)23(a.), which is an update of the dataset from Jenny et al. (2014)56 that combined reconstructed palaeoflood discharges from 1650 to 1852 (black squares) and annual flood discharges from 2010 to 1852 (black and red dots). Red dots denote the floods recorded in the sedimentary sequence among the gauged, annual floods (black dots). Our new record includes 27 on these 32 floods and the five extreme floods correspond well to the largest flood discharges. The lacking floods in our dataset can be related to the lower number of sediment cores compared to Jenny et al. (2014)56 and Evin et al. (2019)23. Over the last 2000 years, the new record (d) is compared to the record from Arnaud et al. (2016)60, which correspond to detrital inputs brought by the Rhône River floods to the deepest part of Lake Bourget. These detrital inputs were very low in the oldest part of the record and largely increased during the Little Ice Age. This period of increased detrital inputs corresponds well to higher occurrence of flood events. Therefore, these comparisons support the robustness of our extended Rhône River palaeoflood record.

Extended Data Table 1 List of the 33 existing palaeoflood records reconstructed from lake sediments in the European Alps. List of the 33 existing palaeoflood records reconstructed from lake sediments in the European Alps and selection of the 27 used in this study in bold, with information about location/coordinates, lake catchment characteristics as well as time length and characteristics of records. Abbreviations as follows: Lat. = latitude, Long. = longitude, Flood season: Sp = Spring, S = Summer, A = Autumn, W = Winter and U = Unknown, D = number of dating points (v = varved record), F = number of floods events recorded, M = Magnitude of floods reconstructed, C = Calibrated record and Ref. = reference. * = explanation for the record rejection from the study
Extended Data Table 2 AMS radiocarbon dates for the new Lake Bourget core dataset. AMS radiocarbon dates for the new Lake Bourget core dataset, measured at the Poznań radiocarbon laboratory, calibrated using the IntCal13 calibration curve57. The radiocarbon age in bold was rejected given its old age compared to other (radiocarbon and historical) dates (Extended Data Fig. 3)
Extended Data Table 3 List of the 27 selected palaeoflood records used in this study for the different analyses of flood occurrence and magnitude. List of the 27 selected palaeoflood records used in this study for the different analyses of flood occurrence and magnitude. A record is used for flood occurrence analyses when it fully covers the time period of interest or for flood magnitude analyses when it includes information about magnitude. When a record is used for flood occurrence analyses, a number is marked that corresponds to the mean flood return period of the record for the given period, that is the number of recorded flood events divided by the considered time length. When a record is used for flood magnitude analysis, a number is marked that corresponds to the site number (Nr.) used in Extended Data Table 1 and Fig. 3. The last 150 years cover 1850–2000 CE; the Industrial Era 1800–2000 CE; the Last Millennium 950–1850 CE and the Holocene 9000–1000 years BP
Extended Data Table 4 List of collected temperature records from or close to the European Alps. List of collected temperature records from or close to the European Alps, sorted by time periods of interest, used in this study with information about site/location, archive type, proxy type, season and reference. Note that summer is the main flooding season (Table 1). References are the following: (1) Heiri O., Ilyashuk B., Millet L., Samartin S., Lotter A.F. (2015) Stacking of discontinuous regional palaeoclimate records: Chironomid-based summer temperatures from the Alpine region. The Holocene 25(1) 137–149; (2) Samartin S., Heiri O., Joos F., Renssen H., Franke J., Brönnimann S., Tinner W. (2017) Warm Mediterranean mid-Holocene summers inferred from fossil midge assemblages. Nature Geoscience. DOI: 10.1038/NGEO2891; (3) Büntgen U., Franck D.C., Nievergelt D., Esper J. (2006) Summer Temperature Variations in the European Alps, A.D. 755–2004, Journal of Climate, 19, 5606–5623; (4) Büntgen U., Tegel W., Nicolussi K., McCormick M., Frank D., Trouet V., Kaplan J.O., Herzig F., Heussner K.U., Wanner H., Luterbacher J., Esper J. (2011) 2500 Years of European Climate Variability and Human Susceptibility, Science 331, 578; (5) Corona C., Guiot J., Edouard J.L., Chalié F., Büntgen U., Nola P., Urbinati C. (2010) Millennium-long summer temperature variations in the European Alps as reconstructed from tree rings. Clim. Past, 6, 379–400; (6) Larocque-Tobler I., Heiri O., Wehrli M. (2010) Late Glacial and Holocene temperature changes at Egelsee, Switzerland, reconstructed using subfossil chironomids. J Palaeolimnology, 43:649–666; (7) Larocque-Tobler I., Stewart M.M., Quinlan R., Trachsel M., Kamenik C., Grosjean M. (2012) A last millennium temperature reconstruction using chironomids preserved in sediments of anoxic Seebergsee (Switzerland): consensus at local, regional and Central European scales. Quaternary Science Reviews 41, 49–56; (8) Mangini A., Spötl C., Verdes P. (2005) Reconstruction of temperature in the Central Alps during the past 2000 yr from a y18O stalagmite record. Earth and Planetary Science Letters 235, 741– 751; (9) Trachsel M., Kamenik C., Grosjean M., McCarroll S., Moberg A., Brázdil R., Büntgen U., Dobrovolný P., Esper J., Frank D.C., Friedrich M., Glaser R., Larocque-Tobler I., Nicolussi K., Riemann D. (2012) Multi-archive summer temperature reconstruction for the European Alps, AD 1053–1996. Quaternary Science Reviews 46 (2012) 66–79; (10) Auer I, Böhm R, Jurkovic A, Lipa W, Orlik A, Potzmann R, Schöner W, Ungersböck M, Matulla C, Briffa K, Jones PD, Efthymiadis D, Brunetti M, Nanni T, Maugeri M, Mercalli L, Mestre O, Moisselin J-M, Begert M, Müller-Westermeier G, Kveton V, Bochnicek O, Stastny P, Lapin M, Szalai S, Szentimrey T, Cegnar T, Dolinar M, Gajic-Capka M, Zaninovic K, Majstorovic Z, Nieplova E, 2007. HISTALP – Historical instrumental climatological surface time series of the greater Alpine region 1760–2003. International Journal of Climatology 27: 17–46
Extended Data Table 5 Changes in temperature by periods of interest from records of Extended Data Table 3. Changes in temperature by periods of interest from records of Extended Data Table 3. The Neoglacial Period (NP) covers 5000–1000 years BP; the Holocene Thermal Maximum (HTM) 9000–5000 cal. years BP; the Little Ice Age (LIA) 1450–1850 CE and the Medieval Climate Anomaly (MCA) 950–1250 CE. 19th c. = nineteenth century, 20th c. = twentieth century, Diff. = Differences in temperature between sub-periods and Ref. = Reference (see Extended Data Table 4)
Extended Data Table 6 Sign and level of significance of relative changes in flood occurrence. Sign and level of significance of relative changes in flood occurrence obtained using the test of equal proportions as well as sign and level of significance of flood trends obtained respectively using a Poisson regression model with years as covariate and a Chi-square test. Si = sign of the change/trend; - = negative change/trend; + = positive change/trend; S=Level of significance; *** = p < 0.001; ** = p < 0.01; ** = p < 0.1; NA = no result due to the shortness of the record in relation to the studied period (Extended Data Table 2); NA* = no result due to a too limited number of recorded events in relation to the studied period
Extended Data Table 7 Modified Mann-Kendall test of significance of warming/cooling trend. Modified Mann-Kendall test of significance of warming/cooling trend during the Holocene (9000–1000 BP), the Last Millennium (950–1850 CE), the Industrial Era (1800–2000 CE) and subperiods of the Industrial Era. Level of significance: *** = p < 0.001; ** = p < 0.01; ** = p < 0.1. Ref. = Reference (see Extended Data Table 4)

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Wilhelm, B., Rapuc, W., Amann, B. et al. Impact of warmer climate periods on flood hazard in the European Alps. Nat. Geosci. 15, 118–123 (2022). https://doi.org/10.1038/s41561-021-00878-y

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/s41561-021-00878-y

This article is cited by

Search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing