Methane hydrates have drawn the attention of climate scientists in the past decades due to the potency of methane as a greenhouse gas and the widespread occurrence of hydrates both in terrestrial and marine environments, which, if destabilised, could enhance global warming. This study aims to investigate how much impact sediment type has on modeled methane escape at the feather edge of stability for methane hydrates in the high latitude Northern Hemisphere (45° to 75° N). This area is characterised by cool bottom-water temperatures leading to a shallow gas hydrate stability zone (GHSZ), and has been disproportionally influenced by contemporary seawater warming. Calculations were performed to establish the depths of the upper and lower boundaries of the feather edge of the GHSZ. These limits were used to estimate seafloor areas covered by three select sediment types that have different petrophysical properties - hemipelagic clay, calcareous ooze and siliceous ooze. Modeling of methane flux for 300 years following a 3°C warming during the first 100 years was performed using TOUGH + HYDRATE for each of the three sediment types. The sediments behaved significantly differently, with siliceous ooze releasing the most methane gas, and calcareous ooze releasing the least. Estimates of total methane gas release were also performed on the areas covered by the three sediments between latitudes 45° to 75° N, and showed that, over the course of 300 years, up to 5 times the current methane concentration in the atmosphere could become susceptible to leaving methane hydrate reservoirs.
| Identifer | oai:union.ndltd.org:UPSALLA1/oai:DiVA.org:su-192841 |
| Date | January 2021 |
| Creators | Barros Parigi, Rafael |
| Publisher | Stockholms universitet, Institutionen för geologiska vetenskaper |
| Source Sets | DiVA Archive at Upsalla University |
| Language | English |
| Detected Language | English |
| Type | Student thesis, info:eu-repo/semantics/bachelorThesis, text |
| Format | application/pdf |
| Rights | info:eu-repo/semantics/openAccess |
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