US identifies "super-emitter" landfills


Methan Menace? Landfills may be doing far more harm to the planet than the regulating agencies are aware of, according to a years-long aerial survey commissioned by California air-quality regulators. A survey by researchers at the NASA's Jet Propulsion Laboratory and leak-detection firm Scientific Aviation found that so called "super-emitter" landfills accounted for 43 percent of the measured emissions of the potent greenhouse gas methane - outpacing the fossil-fuel and agricultural sectors, leaking methane at rates as much as six times the facility-level estimates from the U.S. Environmental Protection Agency, the news agency Reuters reports. The ten biggest methane-emitting landfills pumped out the gas at rates averaging 2.27 times the federal estimates, which are produced by waste firms using EPA methodology.

The US research might have wide-ranging global implications by showing that landfilling is playing a bigger role in accelerating climate change than regulators previously had believed. The surveys could also reveal that United Nations guidelines for estimating methane emissions that are followed by the major governments including the United States and the European Union, had to be adapted. The United Nations' International Panel on Climate Change (IPCC) issued guidelines for states in 2006 on how to estimate methane emissions from landfills without direct measurements such as aerial surveys. The guidelines suggest making estimations using factors such as the amount and content of waste stored on site and assumed rates of waste decay. According to the News Agency Reuters, the IPCC said it would revisit its guidelines if U.N. member nations asked it to do so.

Methane concentrations in the atmosphere have been rising rapidly in recent years, alarming world governments seeking to cap global warming under the 2015 Paris Agreement. The worrying issue: Methane traps much more heat in the atmosphere than carbon dioxide, although for a shorter period of time. One tonne of methane does about 25 times more damage to the climate over a 100-year period than one tonne of carbon dioxide, according to the EPA. Measuring those concentrations in the atmosphere is relatively easy, but tracking the sources of the emissions is hard. That difficulty has become a major stumbling block for global policy-makers hoping to curb the problem.