Permafrost Thaw in Siberia Creates a Ticking ‘Methane Bomb’ of Greenhouse Gases, Scientists Warn
In 2020, temperatures in the region rose nearly 11 degrees Fahrenheit above normal, causing the limestone to release ancient methane deposits

David Kindy
Correspondent
August 5, 2021

In recent years, climate scientists have warned thawing permafrost in Siberia may be a “methane time bomb” detonating slowly. Now, a peer-reviewed study using satellite imagery and a review by an international organization are warning that warming temperatures in the far northern reaches of Russia are releasing massive measures of methane—a potent greenhouse gas with considerably more warming power than carbon dioxide.

“It’s not good news if it’s right,” Robert Max Holmes, a senior scientist at the Woodwell Climate Research Center, who was not involved in either report, tells Steve Mufson of the Washington Post. “Nobody wants to see more potentially nasty feedbacks and this is potentially one.”

Published in the Proceedings of the National Academy of Sciences journal, the study of satellite photos of a previously unexplored site in Siberia detected large amounts of methane being released from exposed limestone. A heat wave in 2020 was responsible for the emissions along two large strips of rock formations in the Yenisey-Khatanga Basin, located several hundred miles north of the Arctic Circle.

Lead author Nikolaus Froitzheim, a geoscientist at the University of Bonn in Germany, is concerned about his study’s findings. Interpreting this data correctly “may make the difference between catastrophe and apocalypse” as the climate crisis worsens, he tells Tara Yarlagadda of Inverse.

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Article | Open access | Published: 23 January 2024
Elevated methane flux in a tropical peatland post-fire is linked to depth-dependent changes in peat microbiome assembly

Aditya Bandla, Hasan Akhtar, Massimo Lupascu, Rahayu Sukmaria Sukri & Sanjay Swarup

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Abstract
Fires in tropical peatlands extend to depth, transforming them from carbon sinks into methane sources and severely limit forest recovery. Peat microbiomes influence carbon transformations and forest recovery, yet our understanding of microbiome shifts post-fire is currently limited. Our previous study highlighted altered relationships between the peat surface, water table, aboveground vegetation, and methane flux after fire in a tropical peatland. Here, we link these changes to post-fire shifts in peat microbiome composition and assembly processes across depth. We report kingdom-specific and depth-dependent shifts in alpha diversity post-fire, with large differences at deeper depths. Conversely, we found shifts in microbiome composition across all depths. Compositional shifts extended to functional groups involved in methane turnover, with methanogens enriched and methanotrophs depleted at mid and deeper depths. Finally, we show that community shifts at deeper depths result from homogeneous selection associated with post-fire changes in hydrology and aboveground vegetation. Collectively, our findings provide a biological basis for previously reported methane fluxes after fire and offer new insights into depth-dependent shifts in microbiome assembly processes, which ultimately underlie ecosystem function predictability and ecosystem recovery.

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Article| Published: 20 April 2023
Wildfire and degradation accelerate northern peatland carbon release

S. L. Wilkinson, R. Andersen, P. A. Moore, S. J. Davidson, G. Granath & J. M. Waddington
Nature Climate Change volume 13, pages 456–461 (2023)Cite this article

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Abstract
The northern peatland carbon sink plays a vital role in climate regulation; however, the future of the carbon sink is uncertain, in part, due to the changing interactions of peatlands and wildfire. Here, we use empirical datasets from natural, degraded and restored peatlands in non-permafrost boreal and temperate regions to model net ecosystem exchange and methane fluxes, integrating peatland degradation status, wildfire combustion and post-fire dynamics. We find that wildfire processes reduced carbon uptake in pristine peatlands by 35% and further enhanced emissions from degraded peatlands by 10%. The current small net sink is vulnerable to the interactions of peatland degraded area, burn rate and peat burn severity. Climate change impacts accelerated carbon losses, where increased burn severity and burn rate reduced the carbon sink by 38% and 65%, respectively, by 2100. However, our study demonstrates the potential for active peatland restoration to buffer these impacts.

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