Netherlands Polar Data Center

Summary

Climate is changing at its fastest rate at northern latitudes where surface temperatures have risen about two to four times above the global average (AMAP, 2021; Meredith et al., 2022; Rantanen et al., 2022). Alongside with gradual warming, extreme weather events are occurring more frequently in arctic regions (Walsh et al., 2020). They can occur year-round and are manifested during summer as droughts or heatwaves (Rantanen et al., 2024; Rietze et al., 2024). During winter, temperature anomalies can expose ecosystems to extreme cold (Graham et al., 2017; Vikhamar-Schuler et al., 2016) or encase plants in ice (Bjerke et al., 2015; Milner et al., 2016). Regardless of their exact nature, extreme events are a major driver of plant damage and mortality, resulting in ‘browning’ of the vegetation (Phoenix et al., 2025). Consequently, gross primary productivity (GPP), which represents CO₂ uptake by plants at the ecosystem level, declines strongly following extreme events (Reichstein et al., 2013). Net ecosystem exchange (NEE), the relatively small difference between GPP and ecosystem respiration (Reco), is therefore typically reduced, decreasing the lank carbon sink capacity (Phoenix et al., 2025). Due to the vast amount of soil organic carbon stored in the Arctic (Schuur et al., 2022; Tarnocai et al., 2009), its carbon balance is relevant to the global climate (Dorrepaal et al., 2009; Maes et al., 2024; Schuur et al., 2022). However, projections of carbon climate feedbacks are challenged by extreme events (Vonk et al., 2025); it is therefore important to enhance understanding of their impacts on major ecosystem types, including the recovery.

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Keywords

• Climate change
• CO2 fluxes
• Drought
• Extreme events
• Peatland
• Plant responses
• Sub-arctic ecosystems
• Tundra heath