The Cryosphere-Carbon on Top of the Earth (CC-Top) Program: Decreasing Uncertainties of Thawing Permafrost and Collapsing Methane Hydrates in the Arctic

Abstract:

The enormous quantities of frozen carbon in the Arctic, presently held in surface soils and in shallow subsea sediments, may act as capacitors of the carbon system, yet uncertainties abound. Our long-term Swedish-Russian-US-EU collaboration through programs such as the International Siberian Shelf Study (ISSS) and the Swedish-Russian-US Investigation of Carbon-Cryosphere-Climate Interactions in the East Siberian Arctic Ocean (SWERUS-C3) provides the observational basis for deeper understanding of the permafrost-shallow hydrate – deep thermogenic system on the vast East Siberian Arctic Shelf (ESAS); a prerequisite for any meaningful predictions of the future trajectory of this Cryosphere-Carbon (CC) system.

The ESAS is the World’s largest yet shallowest shelf sea, holding 80% of coastal PF, 80% of subsea PF and 75% of shallow hydrates. Our findings to date are challenging earlier notions by revealing complexities in terrestrial PF-C remobilization and extensive venting of methane from subsea PF/hydrates. The objective of the CC-Top program is to leverage off the massive ISSS and SWERUS-C3 data collections to transform into quantitative understanding of:

Terrestrial PF-C: CC-Top will in collaboration with other programs (e.g., ARCTIC-GRO) employ great Arctic rivers as natural integrators and by probing the δ13C/Δ14C/molecular fingerprints, apportion release fluxes to different PF-C pools.

The ESAS subsea: CC-Top will use spatially-extensive observations, deep sediment cores and gap-filling expeditions to (i) estimate the distribution and thermal state of subsea PF; (ii) apportion the sources of releasing methane btw subsea-PF, shallow hydrates vs deep-pool seepage, using source-diagnostic triple-isotope fingerprinting.

Slope hydrates: CC-Top will investigate sites discovered in 2008-2014 of collapsed hydrates actively venting methane, to characterize their distribution and properties.

This poster invites discussions on future directions of C-C-C research in the Arctic.