Environmental challenges related to methane hydrate decomposition from climate change scenario and anthropic activities: State of the art, potential consequences and monitoring solutions

• Published in: Earth-Science Reviews
• Main Authors: Ruffine, Livio, Tang, Anh Minh, O'Neill, Nick, Toffin, Laurent M.A.A., Paris, Jean Daniel, Yang, Jinhai, Georgiev, Valentin, Fietzek, Peer, Giustiniani, Michela, Tinivella, Umberta
• Other Authors: Geo-Ocean (GEO-OCEAN), Université de Bretagne Sud (UBS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Navier (NAVIER UMR 8205), École des Ponts ParisTech (ENPC)-Centre National de la Recherche Scientifique (CNRS)-Université Gustave Eiffel, PIP Secretariat, ISPSG, 7 Dundrum Business Pk, Dublin 14 N2Y7, Ireland, Biologie et Ecologie des Ecosystèmes Marins Profonds (BEEP), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Laboratoire des Sciences du Climat et de l'Environnement Gif-sur-Yvette (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Heriot-Watt University Edinburgh (HWU), GeoMarine Ltd, Bulgaria, Kongsberg Maritime, Istituto Nazionale di Oceanografia e di Geofisica Sperimentale (OGS), European Cooperation in Science and Technology, COST, (ES1405), European Project: 101000518,DOORS
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2023
• Subjects: Continental margins; Gas emissions; Methane flux into the atmosphere; Natural gas hydrate deposits; Permafrost and slope stability; [SDU]Sciences of the Universe [physics]; Methane hydrate; permafrost
• Online Access: https://hal.science/hal-04294670; https://hal.science/hal-04294670/document; https://hal.science/hal-04294670/file/EARTH-D-23-00114_R3_HAL.pdf; https://doi.org/10.1016/j.earscirev.2023.104578

International audience Natural gas hydrate deposits (NGHD) have been investigated for decades and represent one of the major methane reservoirs on Earth. They are encountered in sediment of both the continental margins and the permafrost region; areas considered to host amongst the most climate-sensitive ecosystems on Earth. With worldwide temperature increases affecting continental margins and the permafrost, it is important to raise concern about the fate of the NGHD in the coming centuries. Thus, this review presents an overview of the potential consequences of hydrate decomposition on its surrounding areas. It compiles and discusses hydrate-derived methane fluxes measured or inferred from in situ data at several sites by considering both dissociation and dissolution. Depending on the magnitude and the duration of hydrate decomposition, the amounts of methane released can affect to varying degrees the seafloor and the microbial communities that sustain the methane cycle and regulate its transfer from the sediment to the water column; and that aspect is addressed in this review. Here, we also considered the transfer of methane from NGHDs and more broadly from marine emissions to the atmosphere, as it is assumed that such transfer will likely increase in the future. Finally, multi-scale monitoring in space and time is a key element to evaluate the impacts of natural and anthropic perturbations on NGHDs. We thus propose potential engineering solutions for the monitoring of NGHD, mainly based on the long-term deployment of sensor systems.