Mobile Observations and quantification of Methane Emissions to inform National Targeting, Upscaling and Mitigation (MOMENTUM)

Consecutive record-breaking atmospheric CH4 growth rates of 15 and 17 ppb in 2020 and 2021 respectively, have increased the challenge of meeting the Paris Agreement and the Global Methane Pledge. The 2021 UN Global Methane Assessment report highlighted the need for large cuts in methane emissions this decade to slow global temperature rise. Recommendations for remediation targets are urgently required. The UN suggest that within the main source categories the following reductions are possible: 61% from fossil fuel production, distribution and use, 48% from waste processing and waste-to-energy generation, 22% from agriculture.

The UK inventory suggests that CH4 anthropogenic emissions have decreased significantly since 1990, but have remained static for the last 4 years. Our recent mobile measurement campaigns have highlighted potential for further reduction in emissions, particularly in gas distribution infrastructure. Mobile studies are also well-placed to identify so-called super-emitters. Rapid identification and prioritisation for repair or replacement can thus significantly and quickly impact total national emissions, as nations continue to transition to less carbon intensive activities.

The UK aims to meet its 2050 net zero targets with the development of 'green' or 'blue' energy, e.g. waste-to-energy or hydrogen production. An improved quantification of CH4 emissions from these emergent sectors is essential, but little is known about the lifecycle emissions of these sectors at present, making accurate Net Zero assessments impossible. We have already shown that CH4 measurements from biogas plants can be substantial and should be represented as point sources in the national inventory. Modelling of the UK and Ireland network of continuous methane measurement sites has allowed validation of the total UK emission from the inventory. What it does not do is validate emissions from individual source sectors or pinpoint emissions.

Given these knowledge gaps how...