1. Evidence of Ecosystem Tipping Point on St. Lawrence Island: Widespread Lake Drainage Events After 2018.
- Author
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Liu, Aobo, Cheng, Xiao, Wang, Chengxin, and Chen, Yating
- Subjects
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BIRD mortality , *HUMAN ecology , *REMOTE-sensing images , *SEA ice , *ARTIFICIAL satellite tracking , *PERMAFROST ecosystems , *TUNDRAS - Abstract
Influenced by climate change, numerous lakes in permafrost regions are draining, showing significant spatial variability. This study focuses on St. Lawrence Island, where over the last two decades, 771 of 3,271 lakes have drained—a rate around 40 times higher than across the entire northern permafrost region. The surge in lake drainage began in 2018, coinciding with record low sea ice extent in the Bering Sea and unprecedented bird mortalities. Using satellite imagery and machine learning methods, we analyzed drainage events to identify the climatic drivers and potential climate thresholds affecting the island's lake ecosystems. Our findings indicate that autumn peak temperatures above 6°C more than triple the drainage probability, and warming‐induced permafrost thawing may be the direct driver of lake drainage. This research highlights the vulnerability of Arctic lake ecosystems to climate change and assists in developing predictive models for permafrost response, crucial for mitigating impacts on Arctic communities. Plain Language Summary: St. Lawrence Island in the Bering Strait has experienced a drastic increase in lake drainage since 2018, suggesting that the region may be reaching a critical environmental threshold or tipping point. This study used satellite images to track changes in over 3,000 lakes over two decades, discovering that warmer autumns with temperatures above 6°C greatly increase the chance of lakes draining. This indicates that the region's permafrost is becoming unstable due to higher temperatures. Permafrost thawing happens because the increased warmth causes the ice within the permafrost to melt, leading to the collapse and drainage of lakes. Such changes are important not only because they transform the local landscape but also because they can impact the people and wildlife depending on these lakes for survival. Understanding these patterns helps predict future changes and assists in preparing for and possibly preventing the negative impacts of these environmental changes. This study highlights how global warming can lead to significant changes in Arctic regions, which can have lasting effects on both the environment and human communities. Key Points: Over two decades, a quarter of St. Lawrence Island's lakes have drained, a rate 40 times higher than the entire northern permafrost regionSince 2018, the frequency of lake drainage events has increased tenfold, likely linked to autumn heatwaves and permafrost thawingLake drainage probability more than triples when autumn maximum temperatures exceed 6°C, pushing lake ecosystems beyond tipping points [ABSTRACT FROM AUTHOR]
- Published
- 2024
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