Bipolar carbon and hydrogen isotope constraints on the Holocene methane budget

Beck, Jonas; Bock, Michael; Schmitt, Jochen; Seth, Barbara; Blunier, Thomas; Fischer, Hubertus (2018). Bipolar carbon and hydrogen isotope constraints on the Holocene methane budget. Biogeosciences, 15(23), pp. 7155-7175. European Geosciences Union 10.5194/bg-15-7155-2018

beck18bg.pdf - Published Version
Available under License Creative Commons: Attribution (CC-BY).

Download (7MB) | Preview

Atmospheric methane concentration shows a wellknown decrease over the first half of the Holocene following the Northern Hemisphere summer insolation before it started to increase again to preindustrial values. There is a debate about what caused this change in the methane concentration evolution, in particular, whether an early anthropogenic
influence or natural emissions led to the reversal of the atmospheric CH₄ concentration evolution. Here, we present new methane concentration and stable hydrogen and
carbon isotope data measured on ice core samples from both Greenland and Antarctica over the Holocene. With the help of a two-box model and the full suite of CH₄ parameters,
the new data allow us to quantify the total methane emissions in the Northern Hemisphere and Southern Hemisphere separately as well as their stable isotopic signatures, while interpretation of isotopic records of only one hemisphere may lead to erroneous conclusions. For the first half of the Holocene our results indicate an asynchronous decrease in Northern Hemisphere and Southern Hemisphere CH₄ emissions
by more than 30 Tg CH₄ yr⁻¹ in total, accompanied by a drop in the northern carbon isotopic source signature of about -3 ‰. This cannot be explained by a change in the
source mix alone but requires shifts in the isotopic signature of the sources themselves caused by changes in the precursor material for the methane production. In the second half of the Holocene, global CH₄ emissions increased by about 30 Tg CH₄ yr⁻¹, while preindustrial isotopic emission signatures remained more or less constant. However, our results show that this early increase in methane emissions took place in the Southern Hemisphere, while Northern Hemisphere emissions started to increase only about 2000 years ago. Accordingly, natural emissions in the southern tropics appear to be the main cause of the CH₄ increase starting 5000 years before present, not supporting an early anthropogenic influence on the global methane budget by East Asian land use changes.

Item Type:

Journal Article (Original Article)


08 Faculty of Science > Physics Institute > Climate and Environmental Physics
10 Strategic Research Centers > Oeschger Centre for Climate Change Research (OCCR)
08 Faculty of Science > Physics Institute

UniBE Contributor:

Beck, Jonas, Bock, Michael, Schmitt, Jochen, Seth, Barbara, Fischer, Hubertus


500 Science > 530 Physics




European Geosciences Union




Doris Rätz

Date Deposited:

07 Dec 2018 14:58

Last Modified:

05 Dec 2022 15:21

Publisher DOI:





Actions (login required)

Edit item Edit item
Provide Feedback