Articles | Volume 30, issue 12
https://doi.org/10.5194/hess-30-3979-2026
https://doi.org/10.5194/hess-30-3979-2026
Research article
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29 Jun 2026
Research article | Highlight paper |  | 29 Jun 2026

Understanding changes in Iceland's streamflow dynamics in response to climate change

Hordur Bragi Helgason, Andri Gunnarsson, Óli G. B. Sveinsson, and Bart Nijssen

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LamaH-Ice: LArge-SaMple DAta for Hydrology and Environmental Sciences for Iceland
Hordur Bragi Helgason and Bart Nijssen
Earth Syst. Sci. Data, 16, 2741–2771, https://doi.org/10.5194/essd-16-2741-2024,https://doi.org/10.5194/essd-16-2741-2024, 2024
Short summary

Cited articles

Berge, V., Sarrazin, L., Arsenault, R., and Brissette, F.: Streamflow Assessment Toolkit for Changing Conditions, CEATI Report No. T202700-0433, Montreal, QC, Canada, 2021, https://my.ceati.com/research/blta6662929f1ca90c7/reader/a303b3a5-70a0-4ba6-b1ab-b7353a3d70dc?page=7 (access restricted, last access: 26 March 2026), 2021. 
Björnsson, H., Sigurðsson, B., Davíðsdóttir, B., Ólafsson, J., Ástþórsson, Ó., Ólafsdóttir, S., Baldursson, T., and Jónsson, T.: Climate Change in Iceland.Third Assessment Report of the Scientific Committee on Climate Change, Icelandic Meteorological Office, Reykjavik, Iceland, ISBN 978-9935-9414-0-4, https://www.vedur.is/media/loftslag/Skyrsla-loftslagsbreytingar-2018-Vefur-NY.pdf (last access: 27 April 2026), 2018. 
Björnsson, H., Ólafsdóttir, A. H., Sigurðsson, B. D., Katrínardóttir, B., Davíðsdóttir, B., Gunnarsdóttir, G., Aðalgeirsdóttir, G. Th., Sigurðsson, G. M., Ögmundardóttir, H., Pétursdóttir, H., Bárðarson, H., Heiðmarsson, S., and Matthíasdóttir, T.: The Scope and Consequences of Global Climate Change in Iceland, Fourth Assessment Report of the Scientific Committee on Climate Change, Icelandic Meteorological Office, Reykjavik, Iceland, ISBN 978-9935-9414-3-5, 2023. 
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Editorial statement
This is the first comprehensive long-term analysis of Iceland’s streamflow trends, setting a benchmark for future research. The study reveals a surprising shift: while Iceland’s glacial river flows increased over 50 years, they declined over the past 30, challenging assumptions about meltwater contributions. With Iceland’s hydropower reliant on streamflow, these findings raise concerns about future energy security and water management. As climate change disrupts freshwater systems, this study provides crucial insights into shifting hydrology in high-latitude regions.
Short summary
Iceland relies heavily on hydropower, making it important to understand changes in streamflow. Rivers reflect a warming, wetter climate, with rainfall increasingly replacing snowfall. Annual streamflow has generally increased, most notably during the cool season, while summer flows have declined in some non-glacial rivers. Glacial rivers show increasing melt-season flows over 1973–2023 but declining trends over 1993–2023, reflecting glacier retreat and recent North Atlantic sea surface cooling.
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