The Effect of Potential Future Climate Change on the Marine Methane Hydrate Stability Zone

Abstract

The marine gas hydrate stability zone (GHSZ) is sensitive to temperature changes at the seafloor, which likely affected the GHSZ in the past and may do so in the future in response to anthropogenic greenhouse gas emissions. A series of climate sensitivity and potential future climate change experiments are undertaken using the University of Victoria Earth System Climate Model (UVic ESCM) with resulting seafloor temperature changes applied to a simple time-dependent methane hydrate stability model. The global GHSZ responds significantly to elevated atmospheric CO2 over time scales of 103 yr with initial decreases of the GHSZ occurring after 200 yr in shallow high-latitude seafloor areas that underlie regions of sea ice loss. The magnitude and rate of GHSZ change is dependent primarily upon the thermal diffusivity of the seafloor and the magnitude and duration of the seafloor temperature increase. Using a simple approximation of the amount of carbon stored as hydrate in the GHSZ, estimates of carbon mobilized due to hydrate dissociation are made for several potential climate change scenarios.