Advanced isotope analysis provides new insights into global fossil methane emissions

International research published in the Journal of Geophysical Research: Atmospheres uses innovative multi-isotopic atmospheric measurements to provide new insights into global fossil methane emissions.

Principal Accelerator scientist Dr Andrew Smith, co-author of researching methane emissions for over 20 years with A/Prof Vasilii Petrenko and others, has made a significant contribution to this collaboration, improving the accuracy of greenhouse gas emission estimates and supporting more effective global climate mitigation efforts.

The study, led by Dr. Fujita of the Imperial University of London, was led by the Japanese Meteorological Institute of Tsunamis, and used advanced isotope analysis containing stable isotopes of radiocarbon, carbon and hydrogen to accurately distinguish different methane emission sources. This study is the first to integrate multiple isotopic datasets to accurately quantify global methane emissions from fossil fuels, biological sources, geology, and biomass combustion sources over the historical period from 1750 to 2015.

One of the key findings in this study was that global fossil methane emissions were approximately 130 terragrams per year for the period 2003-2012, in close agreement with estimates from the Global Carbon Project, a network of scientists and agencies examining greenhouse gases. To put this into perspective, the Terragram is 1 trillion grams, roughly equivalent to a 400 Olympic-sized swimming pool water mass.

Importantly, this study contradicts previous claims of significantly underrated fossil methane emissions, and clarifies previously contradictory scientific assessments.

Dr. Smith emphasized the importance of multi-ice topic measurements to resolve uncertainties in methane emission inventory. “This study shows that combining multiple isotopic regimes significantly reduces the uncertainty of methane emission estimation. Such accurate data is important for effective climate policy and mitigation strategies,” he said.

ANSTO’s Accelerator Science Center is a global leader in extracting and accurately measuring radiocarbon from extreme carbon samples. This complex process requires the identification and counting of individual atoms by accelerator mass spectrometry.

David Child, leader of the Chemistry Group at the Accelerator Science Center, highlighted the rigorous preparations required for these measurements.

Dr. Bin Yang carried out a demanding graphization process, converting CO2 from an ice core to a graphite target for accelerator measurements.

Dr. Smith took part in a polar sampling expedition and performed radiocarbon measurements using atomic counting techniques from ANSTO’s Accelerator Science Center’s Accelerator Mass Spectrometry.

These results highlight the need for ongoing international cooperation in tracking greenhouse gas emissions and the importance of ongoing research to support accurate climate policy. Ansto is crucial in global efforts to leverage nuclear science to tackle environmental challenges.