Australia: The Land Where Time Began

A biography of the Australian continent 

The Last Glacial Termination Sources of Methane - Measurements of Methane in Greenland Ice

The large rise of atmospheric methane concentration that occurred during the climatic Younger Dryas-Preboreal transition about 11,600 years ago has, according to the authors¹, been widely debated. The contribution to this increase of carbon-14 methane from wetlands should be distinguished from the carbon-14 methane of clathrate origin. In this study the authors¹ measured the carbon-14 concentration in glacial ice to target this transition by the use of samples of ice obtained from a site of ablation in West Greenland. The values of carbon-14 methane they measured were much higher than had been predicted by any scenario, the authors¹ suggesting the carbon-14 methane appears to be elevated by the direct cosmogenic carbon-14 production in ice. To better understand this process and correct the carbon-14 methane of the sample the carbon-14 content of CO was measured, following this correction the results suggested the majority of Younger Dryas-Preboreal increase of methane was likely contributed by wetland sources.

Sources & Further reading

1. Petrenko, Vasilii V., Andrew M. Smith, Edward J. Brook, Dave Lowe, Katja Riedel, Gordon Brailsford, Quan Hua, et al. "14ch4 Measurements in Greenland Ice: Investigating Last Glacial Termination Ch4 Sources." Science 324, no. 5926 (April 24, 2009 2009): 506-08.