Methane emissions from the Nord Stream subsea pipeline leaks
Stephen J. Harris, Stefan Schwietzke, James L. France, Nataly Velandia Salinas, Tania Meixus Fernandez, Cynthia A. Randles, Luis Guanter, Itziar Irakulis‐Loitxate, Andreea Calcan, Ilse Aben, Katarina Abrahamsson, Paul Balcombe, Antoine Berchet, Louise C. Biddle, Henry C. Bittig, C. Böttcher, Timo Bouvard, Göran Broström, Valentin Bruch, Massimo Cassiani, Martyn P. Chipperfield, Philippe Ciais, Ellen Damm, Enrico Dammers, Hugo Denier van der Gon, Matthieu Dogniaux, Emily Dowd, François Dupouy, Sabine Eckhardt, Nikolaos Evangeliou, Wuhu Feng, Mengwei Jia, Fei Jiang, Andrea K. Kaiser-Weiss, Ines Kamoun, Brian J. Kerridge, Astrid Lampert, José Lana, Fei Li, Joannes D. Maasakkers, Jean-Philippe W. MacLean, Buhalqem Mamtimin, Julia Marshall, Gédéon Mauger, Anouar Mekkas, Christian Mielke, Martin Mohrmann, D. P. Moore, Riccardo Nanni, Falk Pätzold, Isabelle Pison, Ignacio Pisso, Stephen M. Platt, Raphaël Préa, Bastien Y. Queste, Michel Ramonet, Gregor Rehder, J. J. Remedios, Friedemann Reum, Anke Roiger, Norbert Schmidbauer, Richard Siddans, Anusha Sunkisala, Rona L. Thompson, Daniel J. Varon, Lucy J. Ventress, Chris Wilson, Yuzhong Zhang
Abstract
The amount of methane released to the atmosphere from the Nord Stream subsea pipeline leaks remains uncertain, as reflected in a wide range of estimates1–18. A lack of information regarding the temporal variation in atmospheric emissions has made it challenging to reconcile pipeline volumetric (bottom-up) estimates1–8 with measurement-based (top-down) estimates8–18. Here we simulate pipeline rupture emission rates and integrate these with methane dissolution and sea-surface outgassing estimates9,10 to model the evolution of atmospheric emissions from the leaks. We verify our modelled atmospheric emissions by comparing them with top-down point-in-time emission-rate estimates and cumulative emission estimates derived from airborne11, satellite8,12–14 and tall tower data. We obtain consistency between our modelled atmospheric emissions and top-down estimates and find that 465 ± 20 thousand metric tons of methane were emitted to the atmosphere. Although, to our knowledge, this represents the largest recorded amount of methane released from a single transient event, it is equivalent to 0.1% of anthropogenic methane emissions for 2022. The impact of the leaks on the global atmospheric methane budget brings into focus the numerous other anthropogenic methane sources that require mitigation globally. Our analysis demonstrates that diverse, complementary measurement approaches are needed to quantify methane emissions in support of the Global Methane Pledge19. Modelling of the evolution of atmospheric methane emissions from the 2022 Nord Stream subsea pipeline leaks shows that the event emitted the largest recorded amount of methane from a single transient event.