How cities are contributing to global warming with the most potent warming gas - Methane

How cities are contributing to global warming with the most potent warming gas - Methane

Groundbreaking research finally sheds light just how exactly cities are warming the climate

Nearly one-fifth of the global methane emissions caused by human activities are a direct result of the activities of cities. However, the majority of cities do not collect data on the wide variety of sources that contribute to the production of this potent greenhouse gas. Methane emissions were detected in the year 2020 by a group lead by McGill University. These emissions came from a variety of sources located all throughout the city of Montreal. The researchers discovered that historic landfills and manholes, which are two of the four most important sources of methane emissions in the city, are not included in the city's municipal greenhouse gas inventories. This makes it difficult to tackle the problem in its entirety or to reach the city's goal of being carbon neutral by the year 2050.

This study offers the first set of direct measurements of methane emissions for the city of Montreal and the province of Quebec as a whole.

Exact sources of methane found

In the study, thorough and exact measurements of methane emissions by source are provided. These measurements include the type of manhole or natural gas infrastructure, for example. The findings, which highlight the importance of gathering information about the specific sources of methane emissions to set in place mitigation strategies that are adapted to each specific situation, should be of interest not only to researchers across Canada and around the world but also to policymakers. This is because the results highlight the fact that it is important to set in place mitigation strategies that are adapted to each specific situation.

According to Mary Kang, an assistant professor in McGill's Department of Civil Engineering and the senior author on the paper recently published in Environmental Science and Technology, "Cities are in a unique position to mitigate methane emissions because they face fewer political challenges than larger bodies such as provinces, states, territories, or countries." It is challenging to design meaningful mitigation measures due to the fact that municipal greenhouse gas inventories frequently underestimate emissions and tend to be dependent on few measurements conducted elsewhere.

Important information regarding the origins of emissions makes it possible to make educated choices.

The team measured methane emissions from over 600 different sources across the city in order to provide the city with actionable mitigation strategies. These sources included historic landfills and manholes (the second and third largest sources of methane emissions, respectively), as well as leaks from natural gas distribution.

According to James Williams, a PhD student and the first author on the paper, "Making choices about how to reduce methane emissions in an efficient and cost-effective way will involve balancing various considerations, depending on the source of the emissions." [Citation needed] "Making choices about how to reduce methane emissions in an efficient and cost-effective way will involve making choices about how to reduce methane emissions in an "For instance, historic landfills have the potential for the greatest decrease in the volume of methane emissions, but they will require the highest costs of mitigation unless the choice is taken to focus on merely the landfills with the highest methane emissions. Increasing the rate at which high-emitting industrial meters are repaired might significantly lower both the costs of mitigating emissions and the emissions themselves in the case of natural gas leaks. However, applying the same strategy to residential meters would result in less of a decrease in use while incurring a far larger cost.

In order to gain a complete picture of how methane emissions might be lowered, the researchers intend to conduct additional measurements from every source of methane across the city. This will ensure that they are not overlooking the sources that produce the most methane emissions. In addition to that, they intend to investigate the emissions of methane that come from sources such as urban rivers and canals.

Interested in learning even more about the sources of the climate crisis?

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