Finding and fixing gas leaks: Using urban waterways to halt the global rise in methane emissions

Methane is a greenhouse gas with 86 times the global warming potential of carbon dioxide over a 20-year period - the timescale in which global action to reduce carbon emissions and limit catastrophic climate change is needed. Atmospheric methane concentrations have increased by 0.5% per year since 2010, yet to achieve the Paris Climate target limiting global warming to 1.5 degrees Celsius it needs to decrease by 0.9% per year between 2010 and 2050. Roughly half the methane currently in the atmosphere comes from human activity, so addressing human-driven methane emissions is crucial to achieving climate targets.

This fellowship will allow me to build a team to help address the global rise in methane emissions. This will be achieved via three work packages (WPs) that deliver technical solutions to key challenges standing in the way of a reduction in human-driven methane emissions. These technical solutions will be developed and applied in urban waterways (city rivers and canals) because these systems can act as conduits for human-driven methane emissions to the atmosphere. Urban waterways can receive a wide range of methane inputs, such as leaky gas and wastewater pipes, and will come under increasing human pressure with more than 5 billion people predicted to live in cities by 2030.

WP1. How do we accurately measure methane emissions? Methane emissions can vary substantially over short spatial (meters) and temporal (hours) scales. The fellowship will deliver instrumentation that can measure methane emissions at spatial and temporal resolutions far surpassing current capabilities, and use it to quantify the contribution of urban waterways to city-scale methane inventories across globally representative locations (UK, Europe, USA, China, Bangladesh).

WP2. Where do methane emissions originate? Methane emissions can be driven directly by human activity, such as leaky pipes, or indirectly by increasing the production of methane in waterways. The techniques used in this fellowship will distinguish natural from human-driven methane by measuring methane/ethane ratios and methane stable (C-13) isotopes at the same high resolutions as in WP1. This will be coupled with targeted methane radio- (C-14) and stable (H-2) isotopes, and geochemical and microbial characterisation of urban waterways. Methane emissions and origin will be mapped out for entire urban waterway networks to determine the key controls of methane release to the atmosphere.

WP3. How do we reduce methane emissions? The mapping of controls on methane release, coupled to detailed microbial characterisation through in-situ and lab incubations, will be used to deliver techniques to a) detect methane leaks, even ones hidden underground, and b) prevent the emission of human-driven methane to the atmosphere by developing bioremediation strategies. For example, how do urban waterway microbes respond to methane leaks, and can we utilise these microbes to rapidly oxidise leaking methane before it reaches the atmosphere?

With a wide range of potential human-driven methane sources, urban waterways provide a strong testbed for the proposed techniques. These techniques will be delivered as a toolbox for research, industry and policy end-users. The toolbox will be developed in collaboration with project partners such as Shell and the UK Environment Agency via a research and industry-led steering committee (see letters of support).

This fellowship provides the flexibility, training and time required to deliver a user-focused toolbox containing:
1) instrumentation to capture the spatial and temporal variability of methane emissions
2) a freely available reference database of methane isotopes and associated geochemical and microbial signatures to identify methane origins
3) tangible solutions to detect and reduce human-driven methane emissions to the atmosphere, developed in collaboration with industry and policy focused partners.