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Overestimating climate warming‐induced methane gas escape from the seafloor by neglecting multiphase flow dynamics
Author(s) -
Stranne C.,
O'Regan M.,
Jakobsson M.
Publication year - 2016
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2016gl070049
Subject(s) - methane , clathrate hydrate , environmental science , global warming , hydrate , dissociation (chemistry) , climate change , lag , geology , atmospheric sciences , chemistry , oceanography , organic chemistry , computer network , computer science
Continental margins host large quantities of methane stored partly as hydrates in sediments. Release of methane through hydrate dissociation is implicated as a possible feedback mechanism to climate change. Large‐scale estimates of future warming‐induced methane release are commonly based on a hydrate stability approach that omits dynamic processes. Here we use the multiphase flow model TOUGH + hydrate (T + H) to quantitatively investigate how dynamic processes affect dissociation rates and methane release. The simulations involve shallow, 20–100 m thick hydrate deposits, forced by a bottom water temperature increase of 0.03°C yr −1 over 100 years. We show that on a centennial time scale, the hydrate stability approach can overestimate gas escape quantities by orders of magnitude. Our results indicate a time lag of > 40 years between the onset of warming and gas escape, meaning that recent climate warming may soon be manifested as widespread gas seepages along the world's continental margins.