Potential Instability of Gas Hydrates along the Chilean Margin Due to Ocean Warming

Giulia Alessandrini,Iván De La Cruz Vargas-Cordero,Umberta Tinivella,Michela Giustiniani,Silvia Castellaro

doi:10.3390/geosciences9050234

Giulia Alessandrini, Iván De La Cruz Vargas-Cordero + Show 3 more

Open Access

https://doi.org/10.3390/geosciences9050234

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Abstract

In the last few years, interest in the offshore Chilean margin has increased rapidly due to the presence of gas hydrates. We have modelled the gas hydrate stability zone off Chilean shores (from 33° S to 46° S) using a steady state approach to evaluate the effects of climate change on gas hydrate stability. Present day conditions were modelled using published literature and compared with available measurements. Then, we simulated the effects of climate change on gas hydrate stability in 50 and 100 years on the basis of Intergovernmental Panel on Climate Change and National Aeronautics and Space Administration forecasts. An increase in temperature might cause the dissociation of gas hydrate that could strongly affect gas hydrate stability. Moreover, we found that the high seismicity of this area could have a strong effect on gas hydrate stability. Clearly, the Chilean margin should be considered as a natural laboratory for understanding the relationship between gas hydrate systems and complex natural phenomena, such as climate change, slope stability and earthquakes.

Highlights

Many scientists worldwide have been working to better understand the onshore and offshore distribution of gas hydrate and its stability conditions
GHSZ; methane, gas hydrate could form from the seafloor down to m b.s.f
Along the lower slope, in (b) during that time gas hydrate does not form or dissociate within the GHSZ; and (c) there is no latent which bathymetric depths are as great as km

Summary

Introduction

Many scientists worldwide have been working to better understand the onshore and offshore distribution of gas hydrate and its stability conditions. Any variation in pressure and/or temperature conditions can lead to gas hydrate dissociation [3]. This may occur in the near future, as modelled by several previous studies (e.g., [4]), since the most recent assessment made by International Panel on Climate. Methane is an important greenhouse gas, so after its release into the ocean, it could reach the atmosphere, resulting in positive feedback for global warming, as underlined by previous studies [7,8,9], this is still the subject of debate among the scientific community (i.e., [10,11,12,13]). Many factors prevent the methane from gas hydrate from reaching the atmosphere, such as methane release velocities and rates from the subsurface, and methane oxidation to carbon dioxide by microbial and chemical processes [14]

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