Estimated natural geologic methane emissions from recent studies that used ice core 14C-CH4 measurements compared with recent bottom-up estimates. DOI: https://doi.org/10.1525/elementa.2020.00066.t1
| Study . | Study Type . | Estimated Geologic Emissions (Tg CH4 yr–1) . |
|---|---|---|
| Petrenko et al. (2017) | Top-down ice core 14C (last deglaciation) | <15.4 |
| Hmiel et al. (2020) | Top-down ice core 14C (preindustrial, early industrial) | <5.4 |
| Dyonisius et al. (2020) | Top-down ice core 14C (last deglaciation, early Holocene) | <19 |
| Etiope (2015) | Bottom-up | 45–76 (median 60) |
| Etiope et al. (2019) | Bottom-up | 42.8–49.8 |
| Study . | Study Type . | Estimated Geologic Emissions (Tg CH4 yr–1) . |
|---|---|---|
| Petrenko et al. (2017) | Top-down ice core 14C (last deglaciation) | <15.4 |
| Hmiel et al. (2020) | Top-down ice core 14C (preindustrial, early industrial) | <5.4 |
| Dyonisius et al. (2020) | Top-down ice core 14C (last deglaciation, early Holocene) | <19 |
| Etiope (2015) | Bottom-up | 45–76 (median 60) |
| Etiope et al. (2019) | Bottom-up | 42.8–49.8 |