Estimation of possible climate change impact on methane hydrate in the Arctic Ocean

Abstract

We study the potential impact of a possible warming in the Arctic Ocean in the 21st century on the methane hydrates stability zone. In order to assess the space-time variability of the ocean bottom temperature, we employ a regional version of a coupled ice-ocean model that has been developed at the Institute of Computational Mathematics and Mathematical Geophysics, Siberian Brunch of the Russian Academy of Sciences. This study is based on a combination of the coupled ocean-ice model and a one-dimensional thermal diffusion sediment model. As an atmospheric forcing, some results obtained with CMIP5 climate models simulated with the RCP8.5 scenario (from 2006-2100) are used. We have found that warm North Atlantic water will have a major influence on the Arctic gas hydrates. In such regions as the Barents Sea, the West Svalbard continental margin, and the continental shelf of Norway methane hydrates may exist in shallow waters, where the strongest warming occurs. For this reason, these regions are most vulnerable to releasing methane into the ocean and the atmosphere when the sea water temperature is increased by approximately 2-3 °C. According to our estimates, the seafloor water warming in these areas during the next 100 years may lead to a shift in the upper boundary of the gas hydrates stability zone by 10-110 m.