A new study has found that landfills make substantial contributions to greenhouse gas emissions in four major cities of the world.
- Methane Emissions from Buenos Aires in Argentina, Delhi and Mumbai in India, and Lahore in Pakistan were 1.6 to 2.7 times larger than what was reported in commonly used emission inventories.
- When organic waste like food, wood or paper decomposes, it emits methane into the air. Landfills are the third-largest source of methane emissions globally, after oil and gas systems and agriculture.
- The study, published in Science Advances, is aimed at helping local governments carry out targeted efforts to limit global warming by pinpointing specific sites of major concern.
Methane emission
- Methane (CH4) is a hydrocarbon that is a primary component of natural gas.
- Methane is the primary contributor to the formation of ground-level ozone, a hazardous air pollutant and greenhouse gas, exposure to which causes 1 million premature deaths every year.
- Methane is also a powerful greenhouse gas. Over a 20-year period, it is 80 times more potent at warming than carbon dioxide.
- Methane is the second most abundant anthropogenic GHG after carbon dioxide (CO2), accounting for about 20 percent of global emissions.
- Methane is more than 25 times as potent as carbon dioxide at trapping heat in the atmosphere.
- Methane is emitted from a variety of anthropogenic (human-influenced) and natural sources.
- Anthropogenic emission sources include landfills, oil and natural gas systems, agricultural activities, coal mining, stationary and mobile combustion, wastewater treatment, and certain industrial processes.
- Agriculture is the predominant source. Livestock emissions – from manure and gastroenteric releases – account for roughly 32 per cent of human-caused methane emissions.
- Agricultural methane doesn’t only come from animals, though. Paddy rice cultivation – in which flooded fields prevent oxygen from penetrating the soil, creating ideal conditions for methane-emitting bacteria – accounts for another 8 per cent of human-linked emissions.
