What is the significance of methane emissions from landfills?

• A. They contribute to global emissions and environmental concerns
• B. They have negligible environmental impact
• C. They only affect local air quality
• D. They are the primary source of renewable energy

Answer: (A)

Methane emissions from landfills are significant because methane is a much more potent greenhouse gas than CO2, so releasing it from decomposing waste has a large impact on climate. In landfills, organic material breaks down without oxygen, producing methane that, if vented freely, adds substantially to atmospheric greenhouse gases and environmental concerns such as climate change and air-quality effects. The large volumes of waste in many landfills mean that the total methane released can be a major part of human-caused methane emissions. However, this gas can be captured and used for energy, which both reduces emissions and provides a renewable energy source. The idea isn’t that landfill methane is negligible or solely a local issue, nor that the emissions themselves are primarily a renewable-energy source—rather, the key point is their global climate impact and the value of capturing them to mitigate that impact.