21st-century modeled permafrost carbon emissions accelerated by abrupt thaw beneath lakes

• Published in: Nature communications 2018-08, Vol.9 (1), p.3262-11, Article 3262
• Main Authors: Walter Anthony, Katey, Schneider von Deimling, Thomas, Nitze, Ingmar, Frolking, Steve, Emond, Abraham, Daanen, Ronald, Anthony, Peter, Lindgren, Prajna, Jones, Benjamin, Grosse, Guido
• Format: Article
• Language: English
• Subjects: 704/106/125; 704/286; 704/47/4113; Alaska; Carbon; Carbon - chemistry; Carbon 14; Carbon Cycle; Carbon dioxide; Carbon Dioxide - chemistry; Carbon dioxide emissions; Climate models; Conservation of Natural Resources - methods; Conservation of Natural Resources - trends; ENVIRONMENTAL SCIENCES; Fluxes; Freezing; Geography; Geologic Sediments - chemistry; Global Warming; Humanities and Social Sciences; Lakes - chemistry; Methane; Methane - chemistry; Models, Theoretical; multidisciplinary; Permafrost; Permafrost - chemistry; Radiative forcing; Radiocarbon dating; Radiometric dating; Remote sensing; Science; Science (multidisciplinary); Soil - chemistry
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-018-05738-9

Permafrost carbon feedback (PCF) modeling has focused on gradual thaw of near-surface permafrost leading to enhanced carbon dioxide and methane emissions that accelerate global climate warming. These state-of-the-art land models have yet to incorporate deeper, abrupt thaw in the PCF. Here we use model data, supported by field observations, radiocarbon dating, and remote sensing, to show that methane and carbon dioxide emissions from abrupt thaw beneath thermokarst lakes will more than double radiative forcing from circumpolar permafrost-soil carbon fluxes this century. Abrupt thaw lake emissions are similar under moderate and high representative concentration pathways (RCP4.5 and RCP8.5), but their relative contribution to the PCF is much larger under the moderate warming scenario. Abrupt thaw accelerates mobilization of deeply frozen, ancient carbon, increasing 14 C-depleted permafrost soil carbon emissions by ~125–190% compared to gradual thaw alone. These findings demonstrate the need to incorporate abrupt thaw processes in earth system models for more comprehensive projection of the PCF this century. Permafrost carbon feedback modeling has focused on gradual thaw of near-surface permafrost leading to greenhouse gas emissions that accelerate climate change. Here the authors show that deeper, abrupt thaw beneath lakes will more than double radiative forcing from permafrost-soil carbon fluxes this century.