Extreme weather likely to increase methane emissions from landfills

Temperature and rainfall fluctuations are responsible for 13% of methane emissions at one of the largest landfill sites in the world, a new study has found. The researchers say that their models show that in a changing climate with more extreme weather, methane emissions from landfills will increase even more, amplifying global warming.

Methane accounts for approximately 16% of human-related greenhouse gas emissions, with studies estimating that the gas has contributed 30% to global warming since the industrial revolution. Landfills alone account for 19% of anthropogenic methane emissions, making these waste sites the third-largest source of methane after agriculture and the fossil fuel sector. In certain cities the contribution of landfills to total methane emissions can climb even higher. A 2022 study revealed that a single landfill site in Buenos Aires produced half of the city’s methane emissions.

Investigating the Sudokwon Landfill Site in South Korea – one of Asia’s largest – researchers at Seoul National University adapted a widely used machine-learning model to reflect the local environment and calculate methane emissions at site-specific locations. By accounting for composition and degradable organic content of waste, as well as waste composition, waste particle size, temperature, moisture and pH, they showed that their climate-sensitive modelling improved methane emission estimations compared with previous models.

The scientists trained their machine-learning framework with field measurements from the Sudokwon site between 2005 to 2021 before assessing an idealised scenario with a fixed composition and volume of waste. Their model revealed that temperature variations were linked to approximately 6% of methane emissions, while fluctuating precipitation was linked to just over 7%.

The researchers say that adapting emissions calculations to be more climate-responsive and site-specific could help inform mitigation strategies and also help tailor them to landfill type and weather conditions.