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SUMMARY:How do methane emissions from biomass burning and global wetlands 
 respond to abrupt climate change?
DTSTART:20101108T161500
DTSTAMP:20260415T102346Z
UID:5a78c1ad0d5613133270a7fabbab160b67ef925ecf0b2270fa260d05
CATEGORIES:Conferences - Seminars
DESCRIPTION:Melton\, Joe\nThe abrupt warming across the Younger Dryas term
 ination (~11 600 years before present\; YD) was marked by a large increase
  in the global atmospheric methane mixing ratio. This rise has been intens
 ely debated with the majority of the debate centred on the role of 1) glob
 al wetlands\, 2) marine gas hydrates\, and 3) thermokarst lakes. I will pr
 esent a new higher-precision methane stable carbon isotope ratio dataset f
 rom ice sampled at Påkitsoq\, Greenland that shows distinct 13C-enrichmen
 t associated with the YD methane rise. A methane triple mass balance of st
 able carbon and hydrogen isotope ratios and radiocarbon is applied to cons
 train the possible sources responsible for the rise. The mass balance resu
 lts suggest biomass burning (42 - 66% of total methane flux increase) and 
 thermokarst lakes (27 - 59%) as the dominant contributing sources. These r
 esults do not suggest as large a role for either global wetlands or marine
  gas hydrates as commonly proposed. These analytical results have motivate
 d 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 insensitiv
 e to climate changes\, and 2) to investigate the apparent high sensitivity
  of biomass burning to climate change. 
LOCATION:GR A3 31
STATUS:CONFIRMED
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