How do methane emissions from biomass burning and global wetlands respond to abrupt climate change?
Event details
| Date | 08.11.2010 |
| Hour | 16:15 |
| Speaker | Melton, Joe |
| Location |
GR A3 31
|
| Category | Conferences - Seminars |
The abrupt warming across the Younger Dryas termination (~11 600 years before present; YD) was marked by a large increase in the global atmospheric methane mixing ratio. This rise has been intensely debated with the majority of the debate centred on the role of 1) global wetlands, 2) marine gas hydrates, and 3) thermokarst lakes. I will present a new higher-precision methane stable carbon isotope ratio dataset from ice sampled at Påkitsoq, Greenland that shows distinct 13C-enrichment associated with the YD methane rise. A methane triple mass balance of stable carbon and hydrogen isotope ratios and radiocarbon is applied to constrain the possible sources responsible for the rise. The mass balance results suggest biomass burning (42 - 66% of total methane flux increase) and thermokarst lakes (27 - 59%) as the dominant contributing sources. These results do not suggest as large a role for either global wetlands or marine gas hydrates as commonly proposed. These analytical results have motivated further investigations using dynamic global vegetation models (DGVMs). I will describe our in-progress work, using the newly developed ARVE-DGVM, to understand: 1) why global wetlands appear to be relatively insensitive to climate changes, and 2) to investigate the apparent high sensitivity of biomass burning to climate change.
Links
Practical information
- General public
- Free
Contact
- Kaplan, Jed (ARVE)