Abstract
Global warming has been leading to a significant increase in the frequency and intensity of extreme rainfall events, however, few paleoflood records hinder our understanding of its long-term patterns and underlying mechanisms. Here, we present a record of mega-floods over the past 30,000 years revealed by fossil cladoceran and geochemical proxies from Lake YunlongTianchi (YLTC) in western Yunnan, SW China. Seven mega-floods are identified in terms of abrupt changes in percentages of planktonic cladocerans, planktic-to-littoral (P/L) ratios, cladoceran flux, sedimentation rates, and terrestrial elements. They occurred at 20,410, 16,940, 15,340, 13,930, 11,540, 3,730, and 1,270 BP, when the lake catchment witnessed extreme precipitation and reduced land cover. They were triggered by extreme rainfall induced by monsoon instability, and amplified by decreased infiltration capacity due to reduced land cover. Our results suggest that these mega-floods were likely associated with monsoonal precipitation extremes as well as land cover change in the lake catchment. Our findings provide a reference for both understanding the driving mechanisms of mega-floods during geological times in western Yunnan and assessing regional extreme hydrological risks and adaptive strategies under global warming scenarios.
Data availability
The code and datasets generated during the current study are available at https://doi.org/10.5281/zenodo.18923027.
References
He, L., Zhou, T. & Guo, Z. Past warm intervals inform the future South Asian summer monsoon. Nature 641, 653–659 (2025).
Benito, G. et al. Use of systematic, palaeoflood and historical data for the improvement of flood risk estimation. Nat. Hazards. 31, 623–643 (2004).
López-Pujol, J., Zhang, F. M. & Ge, S. Plant biodiversity in China: richly varied, endangered, and in need of conservation. Biodivers. Conserv. 15, 3983–4026 (2006).
Chen, C. J. et al. Karst hydrological changes during the Late-Holocene in Southwestern China. Quat Sci. Rev. 258, 106865 (2021).
An, Z. et al. Glacial-interglacial Indian Summer Monsoon dynamics. Science 333, 719–723 (2011).
Tan, L. et al. High resolution monsoon precipitation changes on southeastern Tibetan Plateau over the past 2300 years. Quat Sci. Rev. 195, 122–132 (2018).
Zhao, K. et al. Late Holocene monsoon precipitation changes in southern China and their linkage to Northern Hemisphere temperature. Quat Sci. Rev. 232, 106191 (2020).
Allan, R. P. & Soden, B. J. Atmospheric warming and the amplification of precipitation extremes. Science 321, 1481–1484 (2008).
Gründemann, G. J., van de Giesen, N., Brunner, L. & van der Ent, R. Rarest rainfall events will see the greatest relative increase in magnitude under future climate change. Commun. Earth Environ. 3, 235 (2022).
Zhou, S., Yu, B. & Zhang, Y. Global concurrent climate extremes exacerbated by anthropogenic climate change. Sci Adv 9, eabo1638 (2023).
Misra, A., White, K., Nsutezo, S. F., Straka, W. & Lavista, J. Mapping global floods with 10 years of satellite radar data. Nat Commun 16, 5762 (2025).
Tellman, B. et al. Satellite imaging reveals increased proportion of population exposed to floods. Nature 596, 80–86 (2021).
Roxy, M. K. et al. A threefold rise in widespread extreme rain events over central India. Nat. Commun. 8, 1–11 (2017).
Bai, Y. et al. Flood complexity and rising exposure risk in High Mountain Asia under climate change. Sci. Bull. 70, 1601–1604 (2025).
Liu, B., Sheng, E., Yu, K., Zhou, K. & Lan, J. Variations in monsoon precipitation over southwest China during the last 1500 years and possible driving forces. Sci. China Earth Sci. 65, 949–965 (2022).
Allen, M. R. & Ingram, W. J. Constraints on future changes in climate and the hydrologic cycle. Nature 419, 224–232 (2002).
Konstali, K., Spengler, T., Spensberger, C. & Sorteberg, A. Atmospheric fronts drive future changes in extratropical extreme precipitation. Geophys Res. Lett 52, e2025GL116032 (2025).
Emile-Geay, J. et al. Links between tropical Pacific seasonal, interannual and orbital variability during the Holocene. Nat. Geosci. 9, 168–173 (2016).
IPCC. AR6 Synthesis Report: Climate Change 2023.
Macdonald, N. Trends in flood seasonality of the River Ouse (Northern England) from archive and instrumental sources since AD 1600. Clim. Change. 110, 901–923 (2012).
Rao, M. P. et al. Seven centuries of reconstructed Brahmaputra River discharge demonstrate underestimated high discharge and flood hazard frequency. Nat Commun 11, 6017 (2020).
Harrison, S., Macklin, M. G., Toonen, W. H. J., Benito, G. & Cohen, K. M. Robust climate attribution of modern floods needs palaeoflood science. Clim. Change. 178, 71 (2025).
Noren, A. J., Bierman, P. R., Steig, E. J., Lini, A. & Southon, J. Millennial-scale storminess variability in the northeastern United States during the Holocene epoch. Nature 419, 821–824 (2002).
Brunck, H., Sirocko, F. & Albert, J. The ELSA-Flood-Stack: A reconstruction from the laminated sediments of Eifel maar structures during the last 60,000 years. Global Planet. Change. 142, 136–146 (2016).
Peng, F. et al. Persistent ENSO forcing on Holocene flooding in the Middle-Lower Yangtze River at millennial timescales. Geophys Res. Lett 51, e2023GL107657 (2024).
Shao, S. et al. Holocene extreme rainstorm flood events in the middle reaches of the Lancang–Mekong River Basin recorded by sediments from Lake Baima. Quat Sci. Rev. 343, 108918 (2024).
Sun, Z. et al. Continuous Holocene streamflow rise and ENSO linked floods in the upper reaches of Yarlung Tsangpo. Geophys Res. Lett 51, e2024GL112804 (2024).
Korhola, A., Tikkanen, M. & Weckström, J. Quantification of Holocene lake-level changes in Finnish Lapland using a cladocera–lake depth transfer model. J. Paleolimnol. 34, 175–190 (2005).
Nevalainen, L., Sarmaja-Korjonen, K. & Luoto, T. P. Sedimentary Cladocera as indicators of past water-level changes in shallow northern lakes. Quat Res. 75, 430–437 (2011).
Wang, D. et al. Spatiotemporal patterns of cladoceran community responses to water level variation in Haixi Lake, southwest China. Inland. Waters. 10, 267–282 (2020).
Sarmaja-Korjonen, K. Correlation of fluctuations in cladoceran planktonic:littoral ratio between three cores from a small lake in southern Finland: Holocene water-level changes. Holocene 11, 53–63 (2001).
Pawłowski, D., Hrynowiecka, A., Luoto, T. P., Nevalainen, L. & Zieliński, T. A lake-depth study of Late Glacial and Holocene oxbow deposits using parallel paleoecological and sedimentological analysis. CATENA 255, 109002 (2025).
Suo, Q. et al. Cladoceran community succession and identification of anthropogenic signals since the 1950s in Lake Tianchi in Yunlong County, northwest Yunnan. J. Lake Sci. 34, 1735–1750 (2022).
Li, Y. et al. Meltwater-Driven Water‐Level Fluctuations of Bosten Lake in Arid China Over the Past 2,000 Years. Geophys Res. Lett 48, 2020GL090988 (2020).
Hu, L. et al. Human impacts on the cladoceran community of Jili Lake, arid NW China, over the past century. J. Paleolimnol. 68, 59–70 (2021).
Eggermont, H., Martens, K. & Preface Cladocera crustaceans: sentinels of environmental change. Hydrobiologia 676, 1–7 (2011).
Cheng, L. et al. Effects of environmental change on subfossil Cladocera in the subtropical shallow freshwater East Taihu Lake, China. CATENA 188, 104446 (2020).
Cheng, L., Xue, B., Yao, S. & Liu, J. Response of Cladocera fauna to environmental change based on sediments from Shengjin Lake, a Yangtze River-connected lake in China. Quat Int. 536, 52–59 (2020).
Hofmann, W. Cladocerans and chironomids as indicators of lake level changes in north temperate lakes. J. Paleolimnol. 19, 55–62 (1998).
Demory, F. et al. Detrital input and early diagenesis in sediments from Lake Baikal revealed by rock magnetism. Global Planet. Change. 46, 145–166 (2005).
Clark, J. S. et al. Drought cycles and landscape responses to past aridity on prairies of the northern Great Plains, USA. Ecology 83, 595–601 (2002).
Yang, Z. Yunlong County Chronicle (Agric. Publ. House, 1992).
Xie, H. et al. Composition of magnetic minerals in Holocene sediments of Lake Bosten, Xinjiang, and implications for depositional environment. J. Arid Reg. 40, 512–522 (2017).
Meyers, P. A. & Lallier-Vergès, E. Lacustrine sedimentary organic matter records of late Quaternary paleoclimates. J. Paleolimnol. 21, 345–372 (1999).
Thorndycraft, V. R. & Benito, G. The Holocene fluvial chronology of Spain: evidence from a newly compiled radiocarbon database. Quat Sci. Rev. 25, 223–234 (2006).
Guo, Y. et al. Investigating extreme flood response to Holocene palaeoclimate in the Chinese monsoonal zone: A palaeoflood case study from the Hanjiang River. Geomorphology 238, 187–197 (2015).
Srivastava, P. et al. Paleofloods records in Himalaya. Geomorphology 284, 17–30 (2017).
Sharma, S., Shukla, A. D., Bartarya, S. K., Marh, B. S. & Juyal, N. The Holocene floods and their affinity to climatic variability in the western Himalaya, India. Geomorphology 290, 317–334 (2017).
Sridhar, A., Maurya, D. M. & Chamyal, L. S. Indicators of Holocene high-stage flood events and tributary confluence migration in the lower Narmada Basin, western India. J Earth Syst. Sci 131, 219 (2022).
Wenxiang, W. & Tungsheng, L. Possible role of the ‘Holocene Event 3’ on the collapse of Neolithic cultures around the Central Plain of China. Quat Int. 117, 153–166 (2004).
Zeng, M. et al. Influence of climate change on the evolution of ancient culture from 4500 to 3700 cal. yr BP in the Chengdu Plain, upper reaches of the Yangtze River, China. CATENA 147, 742–754 (2016).
Jia, T. et al. Depositional evidence of palaeofloods during 4.0–3.6 ka BP at the Jinsha site, Chengdu Plain, China. Quat Int. 440, 78–89 (2017).
Huang, M. et al. The Hongqiaocun Site: The earliest evidence of ancient flood sedimentation of the water conservancy facilities in the Chengdu Plain, China. CATENA 185, 104296 (2020).
Guo, Y., Ge, Y., Mao, P. & Liu, T. A comprehensive analysis of Holocene extraordinary flood events in the Langxian gorge of the Yarlung Tsangpo River valley. Sci. Total Environ. 863, 160942 (2023).
Sridhar, A. A mid–late Holocene flood record from the alluvial reach of the Mahi River, Western India. CATENA 70, 330–339 (2007).
Wen, K. The Meteorological Disaster Encyclopedia of China: Chongqing 96 (China Meteorol., 2008).
Kale, V. S., Singhvi, A. K., Mishra, P. K. & Banerjee, D. Sedimentary records and luminescence chronology of Late Holocene palaeofloods in the Luni River, Thar Desert, northwest India. CATENA 40, 337–358 (2000).
Sridhar, A. et al. Late Holocene flooding history of a tropical river in western India in response to southwest monsoon fluctuations: A multi-proxy study from lower Narmada valley. Quat Int. 371, 181–190 (2015).
Sridhar, A. & Chamyal, L. S. Implications of palaeohydrological proxies on the late Holocene Indian Summer Monsoon variability, western India. Quat Int. 479, 25–33 (2018).
Chamyal, L. S. & Sridhar, A. Palaeoflood hydrology of the fluvial continental records of western India: A synthesis. J. Palaeosciences. 70, 317–326 (2021).
Barendrecht, M. H. et al. Exploring drought-to‐flood interactions and dynamics: A global case review. WIREs Water. 11, e1726 (2024).
Shen, J. et al. Ti content in Huguangyan maar lake sediment as a proxy for monsoon-induced vegetation density in the Holocene. Geophys. Res. Lett. 40, 5757–5763 (2013).
She, D., Liu, D., Xia, Y. & Shao, M. Modeling effects of land use and vegetation density on soil water dynamics: Implications on water resource management. Water Resour. Manag. 28, 2063–2076 (2014).
Zhang, W. et al. Peatland development and climate changes in the Dajiuhu basin, central China, over the last 14,100 years. Quat Int. 425, 273–281 (2016).
Cai, Y. et al. Variability of stalagmite-inferred Indian monsoon precipitation over the past 252,000 y. Proc. Natl. Acad. Sci. U S A. 112, 2954–2959 (2015).
Dutt, S. et al. Abrupt changes in Indian summer monsoon strength during 33,800 to 5500 years B.P. Geophys. Res. Lett. 42, 5526–5532 (2015).
Zhang, E. et al. Summer temperature fluctuations in Southwestern China during the end of the LGM and the last deglaciation. Earth Planet. Sci. Lett. 509, 78–87 (2019).
Fleitmann, D. et al. Holocene forcing of the Indian monsoon recorded in a stalagmite from southern Oman. Science 300, 1737–1739 (2003).
Fattet, M. et al. Effects of vegetation type on soil resistance to erosion: Relationship between aggregate stability and shear strength. CATENA 87, 60–69 (2011).
Zhang, C. et al. Soil erosion in relation to climate change and vegetation cover over the past 2000 years as inferred from the Tianchi lake in the Chinese Loess Plateau. J. Asian Earth Sci. 180, 103850 (2019).
Sheng, E. et al. Hydroclimatic variations in southwestern China during the Middle to Late Holocene transition and effects on the evolution of Late Neolithic cultures in the upper Yangtze River Valley. Quat Sci. Rev. 352, 109225 (2025).
Dearing, J. A. et al. Using multiple archives to understand past and present climate–human–environment interactions: the Lake Erhai catchment, Yunnan Province, China. J. Paleolimnol. 40, 3–31 (2008).
Yuan, D. et al. Timing, duration, and transitions of the Last Interglacial Asian Monsoon. Science 304, 575–578 (2004).
Liu, G. et al. On the glacial-interglacial variability of the Asian monsoon in speleothem δ¹⁸O records. Sci Adv 6, eaay8189 (2020).
Wu, Y. et al. Northern Hemisphere summer insolation and ice volume driven variations in hydrological environment in Southwest China. Geophys Res. Lett 50, e2023GL105664 (2023).
Kong, X., Yan, Q. & Wei, T. Weakened and lowered sensitivity of extreme precipitation over the global land monsoon regions during the Last Glacial Maximum. Geophys Res. Lett 51, e2024GL110867 (2024).
Partin, J. W., Cobb, K. M., Adkins, J. F., Clark, B. C. & Fernandez, D. L. Millennial-scale trends in west Pacific warm pool hydrology since the Last Glacial Maximum. Nature 449, 452–455 (2007).
Anand, P. et al. Coupled sea surface temperature-seawater δ¹⁸O reconstructions in the Arabian Sea at the millennial scale for the last 35 ka. Paleoceanography 23, PA4207 (2008).
Schneider, T., Bischoff, T. & Haug, G. H. Migrations and dynamics of the intertropical convergence zone. Nature 513, 45–53 (2014).
Zhang, E. et al. Holocene extreme hydroclimate events in the Asian monsoon region were more frequent during cooler intervals. Commun Earth Environ 4, 344 (2023).
Masoum, A., Nerger, L., Willeit, M., Ganopolski, A. & Lohmann, G. Lessons From Transient Simulations of the Last Deglaciation With CLIMBER-X: GLAC1D Versus PaleoMist. Geophys Res. Lett 51, e2023GL107310 (2024).
Zhao, J. et al. Resonant Asian Monsoon During Intermediate Conditions of the Last Deglaciation: Insights From Speleothem Records. J Geophys. Res. Atmos 130, e2024JD042523 (2025).
Jiang, W. et al. Synchronous Strengthening of the Indian and East Asian Monsoons in Response to Global Warming Since the Last Deglaciation. Geophys. Res. Lett. 46, 3944–3952 (2019).
Sirocko, F., Garbe-Schonberg, D., McIntyre, A. & Molfino, B. Teleconnections Between the Subtropical Monsoons and High-Latitude Climates During the Last Deglaciation. Science 272, 526–529 (1996).
Overpeck, J., Anderson, D., Trumbore, S. & Prell, W. The southwest Indian Monsoon over the last 18 000 years. Clim. Dyn. 12, 213–225 (1996).
Rao, V. P., Kessarkar, P. M., Patil, S. K. & Ahmad, S. M. Rock magnetic and geochemical record in a sediment core from the eastern Arabian Sea: Diagenetic and environmental implications during the late Quaternary. Palaeogeogr Palaeoclimatol Palaeoecol. 270, 46–52 (2008).
Kessarkar, P. M., Purnachadra Rao, V., Naqvi, S. W. A. & Karapurkar, S. G. Variation in the Indian summer monsoon intensity during the Bølling-Ållerød and Holocene. Paleoceanography 28, 413–425 (2013).
Govil, P. & Divakar Naidu, P. Variations of Indian monsoon precipitation during the last 32 kyr reflected in the surface hydrography of the Western Bay of Bengal. Quat Sci. Rev. 30, 3871–3879 (2011).
Prajith, A. & Tyagi, A. John Kurian, P. Changing sediment sources in the Bay of Bengal: Evidence of summer monsoon intensification and ice-melt over Himalaya during the Late Quaternary. Palaeogeogr Palaeoclimatol Palaeoecol. 511, 309–318 (2018).
Thamban, M., Purnachandra Rao, V., Schneider, R. R. & Grootes, P. M. Glacial to Holocene fluctuations in hydrography and productivity along the southwestern continental margin of India. Palaeogeogr Palaeoclimatol Palaeoecol. 165, 113–127 (2001).
Liu, D. et al. Contrasting patterns in abrupt Asian summer monsoon changes in the last glacial period and the Holocene. Paleoceanogr Paleoclimatol. 33, 214–226 (2018).
Xue, Y. Preliminary study on the plant remains from the Haimenkou site in Jianchuan, Yunnan [Dissertation]. Peking Univ., Beijing (2010).
Yang, F., Wan, Y. & Hu, C. Yunnan Archaeology: 1979–2009 (Yunnan People’s Publ. House, 2010).
Hillman, A. L., Abbott, M. B., Yu, J., Bain, D. J. & Chiou-Peng, T. Environmental legacy of copper metallurgy and Mongol silver smelting recorded in Yunnan Lake sediments. Environ. Sci. Technol. 49, 3349–3357 (2015).
Yuan, G. History of Agricultural Social Change in Yunnan (Yunnan People’s Publ. House, 2017).
Yang, L. E., Bork, H. R., Fang, X. & Mischke, S. (eds) Socio-environmental dynamics along the historical Silk Road (Springer Int. Publ., 2019).
Alaoui, A., Rogger, M., Peth, S. & Blöschl, G. Does soil compaction increase floods? A review. J. Hydrol. 557, 631–642 (2018).
Evans, M. G., Burt, T. P., Holden, J. & Adamson, J. K. Runoff generation and water table fluctuations in blanket peat: Evidence from UK data spanning the dry summer of 1995. J. Hydrol. 221, 141–160 (1999).
Descroix, L. et al. Spatio-temporal variability of hydrological regimes around the boundaries between Sahelian and Sudanian areas of West Africa: A synthesis. J. Hydrol. 375, 90–102 (2009).
Zou, Y. et al. Abnormal reduction in Indian monsoon rainfall during current warm period from the Holocene evolution perspective. Quat Sci. Rev. 356, 109316 (2025).
Bird, B. W. et al. Late-Holocene Indian summer monsoon variability revealed from a 3300-year-long lake sediment record from Nir’pa Co, southeastern Tibet. Holocene 27, 541–552 (2017).
Cao, P. et al. Sedimentary responses to the Indian Summer Monsoon variations recorded in the southeastern Andaman Sea slope since 26 ka. J. Asian Earth Sci. 114, 512–525 (2015).
Laskar, J. et al. A long-term numerical solution for the insolation quantities of the Earth. Astron. Astrophys. 428, 261–285 (2004).
McManus, J. F., Francois, R., Gherardi, J. M., Keigwin, L. D. & Brown-Leger, S. Collapse and rapid resumption of Atlantic meridional circulation linked to deglacial climate changes. Nature 428, 834–837 (2004).
Lippold, J. et al. Does sedimentary 231Pa/230Th from the Bermuda Rise monitor past Atlantic Meridional Overturning Circulation? Geophys Res. Lett 36, L12601 (2009).
Lu, F., Pausata, F. S. R. & Mohtadi, M. Reconstruct the intertropical convergence zone over the Indo-Pacific Warm Pool with extended records and empirical orthogonal function. Proc. Natl. Acad. Sci. U. S. A. 121, (2024).
Cheng, H. et al. The Asian monsoon over the past 640,000 years and ice age terminations. Nature 534, 640–646 (2016).
Zhang, X. et al. Quantification of Asian monsoon variability from 68 ka BP through pollen-based climate reconstruction. Sci. Bull. 68, 713–722 (2023).
Zhao, C. et al. Possible obliquity-forced warmth in southern Asia during the last glacial stage. Sci. Bull. 66, 1136–1145 (2021).
Zhang, S. & Dong, L. Comprehensive scientific investigation report of the Yunlong Tianchi National Nature Reserve, Yunnan. Yunnan Sci. Technol. Press, 58–59 (2022).
Blaauw, M. Methods and code for ‘classical’ age-modelling of radiocarbon sequences. Quat Geochronol. 5, 512–518 (2010).
Sweetman, J. N., LaFace, E., Rühland, K. M. & Smol, J. P. Evaluating the response of Cladocera to recent environmental changes in lakes from the central Canadian Arctic treeline region. Arct. Antarct. Alp. Res. 40, 584–591 (2008).
Szeroczyńska, K. & Sarmaja-Korjonen, K. Atlas of subfossil Cladocera from Central and Northern Europe (Friends of the Lower Vistula Society, 2007).
Mottl, O. et al. Rate-of-change analysis in paleoecology revisited: A new approach. Rev. Palaeobot Palynol. 293, 104483 (2021).
Malhotra, P., Vig, L., Shroff, G. & Agarwal, P. Long short term memory networks for anomaly detection in time series. In Proceedings of the European Symposium on Artificial Neural Networks, Computational Intelligence and Machine Learning (ESANN), 89–94 (2015).
Funding
This research was funded by the National Natural Science Foundation of China (Nos. 42177437 and 42167065) and Yunnan Normal University Doctoral Fund (YJSJJ25-A09).
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Q.Suo and C.S. conceived the project. Q.Suo, Q.Sun, H.M., L.H., and C.S. conducted field work. Q.Suo, Q.Shi, and M.W. performed laboratory analyses. Q.Suo, Q.Shi, and Q.Sun. analysed data. Q.Suo, L.X. and C.S. interpreted the data. Q.Suo and C.S. wrote the paper with input from all authors.
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Suo, Q., Sun, Q., Shi, Q. et al. Mega-floods over the past 30,000 years in western yunnan, southwest China. Sci Rep (2026). https://doi.org/10.1038/s41598-026-46783-5
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DOI: https://doi.org/10.1038/s41598-026-46783-5
