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Abstract Lake surface temperature extremes have shifted over recent decades, leading to significant ecological and economic impacts. Here, we employed a hydrodynamic-ice model, driven by climate data, to reconstruct over 80 years of lake surface temperature data across the world’s largest freshwater bodies. We analyzed lake surface temperature extremes by examining changes in the 10th and 90th percentiles of the detrended lake surface temperature distribution, alongside heatwaves and cold-spells. Our findings reveal a 20–60% increase in the 10 and 90 percentiles detrended lake surface temperature in the last 50 years relative to the first 30 years. Heatwave and cold-spell intensities, measured via annual degree days, showed strong coherence with the Arctic Oscillation (period: 2.5 years), Southern Oscillation Index (4 years), and Pacific Decadal Oscillation (6.5 years), indicating significant links between lake surface temperature extremes and both interannual and decadal climate teleconnections. Notably, heatwave and cold-spell intensities for all lakes surged by over 100% after 1996 or 1976, aligning with the strongest El-Niño and a major shift in the Pacific Decadal Oscillation, respectively, marking potential regional climate tipping points. This emphasizes the long-lasting impacts of climate change on large lake thermodynamics, which cascade through larger ecological and regional climate systems.
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Abrupt transformation of west Greenland lakes following compound climate extremes associated with atmospheric rivers
Arctic ecosystems are affected by accelerated warming as well as the intensification of the hydrologic cycle, yet understanding of the impacts of compound climate extremes (e.g., simultaneous extreme heat and rainfall) remains limited, despite their high potential to alter ecosystems. Here, we show that the aquatic ecosystems in historically arid west Greenland have undergone an ecological transformation after a series of atmospheric rivers that simultaneously produced record heat and rainfall hit the region in autumn 2022. We analyzed a unique, long-term lake dataset and found that compound climate extremes pushed Arctic lakes across a tipping point. As terrestrial–aquatic linkages were strengthened, lakes synchronously transformed from “blue” lakes with high transparency and low pelagic primary production to “brown” in less than a year, owing to a large influx of dissolved organic material and metals, with iron concentrations increasing by more than two orders of magnitude. The browning of lake waters reduced light penetration by 50% across lakes. The resulting light limitation altered plankton distributions and community structure, including a major reduction in prokaryotic diversity and an increase in algal groups capable of metabolizing organic carbon sources. As a result, lakes shifted from being summer carbon sinks to sources, with a >350% increase in carbon dioxide flux from lakes to the atmosphere. The remarkably rapid, coherent transformation of these Arctic ecosystems underscores the synergistic and unpredictable impacts of compound extreme events and the importance of their seasonal timing, especially in regions with negative moisture balance.
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- PAR ID:
- 10568209
- Publisher / Repository:
- Oxford University Press
- Date Published:
- Journal Name:
- Proceedings of the National Academy of Sciences
- Volume:
- 122
- Issue:
- 4
- ISSN:
- 0027-8424
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript
- Journal Article:
- https://doi.org/10.1073/pnas.2413855122
