Climate impact of methane emissions from gas developments

Dimitri Lafleur completed his PhD with the University of Melbourne in 2018, and is now a Postdoctoral Fellow at CSIRO. Dimitri is from the Netherlands, but has been living in Australia for the last 11 years. He graduated from the University of Utrecht with an MSc in geology/geophysics and has been working as a geoscientist for Shell for 11 years in the Netherlands and Australia. He returned to academic life in pursuit of a PhD researching the climate impact of emissions of fossil fuel exports and unconventional gas in particular.  

In Australia these cross-boundary effects of both the induced domestic emissions due to new gas exports and the potential contributions to overseas emissions from burned fossil fuels are clearly important to inform any policy discussions.

Firstly, Australia allows for the extraction of coal and gas that is exported and subsequently burned by importing nations, causing emissions in those nations. Australia's historical and current emissions from fossil fuel production are unknown. Also, there is no database available that allows allocation of current world emissions and historical emissions by fossil fuel producing country, as so far historical estimates have either looked at territorial or consumption based emissions. This despite the fact that discussions on historical responsibility for climate change gain new traction with every major climate-related disaster and the question of who might pay one day. 

Secondly, there is a need to better understand the fugitive emissions from unconventional natural gas extraction. Over one third of Australian gas production comes from coal seam gas extraction and the vast majority is exported, but estimates of the fugitive emissions from unconventional gas infrastructure are predominantly relying on possibly outdated emission factors. This is despite the empirical evidence from the United States that fugitive emissions from unconventional gas are much higher in various sedimentary basins. Furthermore, the reported fugitive emissions from gas production in the Australian emission inventory are much lower than those of other gas producing nations. There is little data on the fugitive emissions from Australian unconventional gas developments. The lack of emission data fuels the possibility that emissions are larger than anticipated given the amount of infrastructure, the atypical extraction process of coal seam gas and the local geology. Data on, and understanding the scale of, migratory emissions is lacking completely. Migratory emissions refer to methane emissions that leak through faults and stratigraphy from a subsurface source into the atmosphere. While natural gas is considered a solution for a move away from higher emission coal, underreporting of these emissions would make gas look like a lower emission fossil fuel than it really is. This could affect the optimal domestic emission reductions strategies elsewhere. 

Thus, this thesis investigates the scientific foundation of these effects and provides a quantitative basis for discussion. 

Supervisors: Prof. Peter Rayner, A/Prof. Malte Meinshausen, Prof. Mike Sandiford