The Arctic Methane and Permafrost Challenge (AMPAC) is an ESA and NASA collaborative community initiative to help tackle the scientific challenges in estimating current and future methane fluxes from the Arctic region. Under this umbrella, AMPAC-Net is an ESA funded project to foster collaborations and scientific exchange on the Arctic methane challenge. The six guiding goals are: (1) Engaging the community, workshops, dialogue (2) Advancing EO products, novel methods, algorithms (3) Reconciling bottom-up & top-down approaches (4) Data catalogues, open science and data sharing (5) Summer schools, training, outreach and education and (6) Networking, including supporting scientific exchanges. The initiative is further supported through the ESA funded project MethaneCamp with focus on improvement of satellite retrievals of methane concentrations in the Arctic.

As part of AMPAC-Net, relevant already published datasets have been included into a catalogue (https://apgc.awi.de/group/about/ampac) including datasets for methane (in situ, satellite derived concentrations, airborne campaign data, inversions etc.) and landcover/wetlands.

Bottom-up estimates rely on accurate representation of Arctic landcover, especially wetlands as potential methane source. The heterogeneity of Arctic landcover requires high spatial resolution and appropriate thematic content. Existing circumpolar landcover data and a range of in situ data have been investigated with respect to wetlands and heterogeneity supporting AMPAC goals, especially the new landcover units derived from Copernicus Sentinel-1 (Synthetic Aperture Radar) and Sentinel-2 (multispectral) satellite missions (ESA Permafrost_CCI, 10 m).

Further on, the potential of new, approved European satellite missions for AMPAC goals is discussed.

https://www.ampac-net.info/

https://methanecamp.fmi.fi/

How to cite: Bartsch, A., Hugelius, G., Grosse, G., Hashemi, J., Treat, C., Goeckede, M., Tamminen, J., Fix, A., Sachs, T., Houweling, S., Bergstedt, H., and Widhalm, B.: Remote sensing supporting the Arctic Methane and Permafrost Challenge (AMPAC), EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-14843, https://doi.org/10.5194/egusphere-egu24-14843, 2024.

Cross-scale feedbacks between hydrology, vegetation, permafrost thaw, and wildfire will drive Arctic carbon cycle responses including methane emissions to the atmosphere. This presentation will summarize recent findings from several large-scale empirical projects examining interactions between disturbance regimes and their consequences for vegetation and carbon storage and fluxes in interior Alaska and northwestern Canada.  A long-term monitoring project at the Alaska Peatland Experiment (APEX) found that early onset of abrupt thaw, driven by active layer thickening with no visible thermokarst, was predicted by changes in the moss community and stimulated CH₄ fluxes 5-fold, accounting for 30% of the total annual thaw-driven increase in CH₄. Methane emissions at several sites in interior Alaska were sensitive to rainfall and surface moisture conditions, with spring rain events stimulating soil warming and methane fluxes. Finally, new tools have allowed us to identify and examine forests and peatlands that experienced overwintering or zombie fire conditions, with early results showing interesting regional differences in how these novel fire conditions influence fuel combustion and carbon release.  Results from recent and ongoing studies will be used to frame forward-looking research questions and approaches urgently needed to better understand the fate of permafrost carbon.  In particular, I will discuss several efforts to incorporate abrupt thaw into circumpolar upscaling and modeling studies. Unlike active layer thickening, abrupt thaw impacts meters of soil rapidly, occurs on a fine-scale not easily detected in remote sensing products, and is further destabilized by rainfall, wildfire, and vegetation change.

How to cite: Turetsky, M.: Arctic methane emissions under novel disturbance regimes: interactions between permafrost thaw, changing precipitation, and peat fires, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4779, https://doi.org/10.5194/egusphere-egu24-4779, 2024.

Rapid Arctic environmental change affects the entire Earth system as thawing permafrost ecosystems release greenhouse gases to the atmosphere. The permafrost soil carbon pool contains three times as much carbon as in the atmosphere, with 1440-1600 Pg C known, and another ~960 Pg C in other deep sediments and subsea. The permafrost region contains 50% of the soil carbon found in all other Earth’s biomes (0-3m) in only 15% of the global soil area, and this is likely a minimum. Understanding how much permafrost carbon will be released, over what time frame, and what the relative emissions of carbon dioxide and methane will be is key for understanding the impact on global climate. In addition, the response of vegetation in a warming climate has the potential to offset at least some of the accelerating feedback to the climate from permafrost carbon. Temperature, organic carbon, and ground ice are key regulators for determining the impact of permafrost ecosystems on the global carbon cycle. Together, these encompass services of permafrost relevant to global society as well as to the people living in the region and help to determine the landscape-level response of this region to a changing climate.

Nine scenarios of cumulative net carbon dioxide and methane emissions over this century were developed to encompass the full range permafrost carbon emissions projections linked to global and Arctic warming. These cumulative permafrost carbon emission scenarios range from 55 to 230 Pg C (C-CO₂-equivalent units) and represent future Arctic carbon emissions that can be compared relative to national-level emissions that are the focus of climate change mitigation conversations. This helps to place these scenarios alongside policy conversations aimed at reducing national greenhouse gas emissions. Many of the modeled climate change trajectories where mitigation of human carbon emissions leads to various global temperature targets do not necessarily contain all of the detailed information for the Arctic carbon cycle as compared to the projections reviewed here. In this way, it can be helpful to view potential Arctic carbon emissions as the equivalent of an additional large industrialized nation of carbon emissions that must be accounted for in order to reach specific temperature targets. Arctic carbon emissions accelerate climate change, adding 10-15% to future fossil fuel emissions, potentially decreasing the land carbon sink by 33-50%. Accounting for these additional greenhouse gas emissions will help to slow climate change and potentially avoid Arctic carbon cycle surprises from abrupt thaw and other threshold events.

How to cite: Schuur, E. (. and the Permafrost Carbon Network: Permafrost and Climate Change: Carbon Cycle Feedbacks From the Warming Arctic, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13797, https://doi.org/10.5194/egusphere-egu24-13797, 2024.