Global geological methane emissions: an update of top-down and bottom-up estimates
| Autor: | S. Schwietzke, Giuseppe Etiope |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: |
Atmospheric Science
Environmental Engineering 010504 meteorology & atmospheric sciences Earth science Flux Oceanography 01 natural sciences law.invention bottom-up Atmosphere 03 medical and health sciences Ice core law Radiocarbon dating Geological methane Seepage Global emission estimates Bottom-up Top-down Geothermal gradient lcsh:Environmental sciences 030304 developmental biology 0105 earth and related environmental sciences lcsh:GE1-350 0303 health sciences geography global emission estimates geography.geographical_feature_category seepage Ecology Geology Geotechnical Engineering and Engineering Geology geological methane Volcano top-down Environmental science Sedimentary rock Mud volcano |
| Zdroj: | Elementa: Science of the Anthropocene, Vol 7, Iss 1 (2019) Elem Sci Anth; Vol 7 (2019); 47 |
| ISSN: | 2325-1026 |
| Popis: | A wide body of literature suggests that geological gas emissions from Earth’s degassing are a major methane (CH4) source to the atmosphere. These emissions are from gas-oil seeps, mud volcanoes, microseepage and submarine seepage in sedimentary (petroleum-bearing) basins, and geothermal and volcanic manifestations. Global bottom-up emission estimates, ranging from 30 to 76 Tg CH4 yr–1, evolved in the last twenty years thanks to the increasing number of flux measurements, and improved knowledge of emission factors and area distribution (activity). Based on recent global grid maps and updated evaluations of mud volcano and microseepage emissions, the global geo-CH4 source is now (bottom-up) estimated to be 45 (27–63) Tg yr–1, i.e., ~8% of total CH4 sources. Top-down verifications, based on independent approaches (including ethane and isotopic observations) from different authors, are consistent with the range of the bottom-up estimate. However, a recent top-down study, based on radiocarbon analyses in polar ice cores, suggests that geological, fossil (14C-free) CH4 emissions about 11,600 years ago were much lower ( |
| Databáze: | OpenAIRE |
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