Example
A closed site can keep producing methane for decades as buried waste continues to break down.
The catch
Site-level estimates carry wide uncertainty unless backed by direct measurement.
Related terms
Methane, Anthropogenic methane, Biogenic methane, Flaring, Fossil methane, Fugitive emissions
In more depth
Landfill methane, explained.
Landfill methane is one of the more fixable climate problems, because the source stays in one place and the remedies are well known. Organic waste diversion works upstream by keeping food and garden waste out of the site. Gas collection works downstream by capturing what still forms.
Timing complicates both. Food scraps break down fast, and much of their methane can form while a cell is still open and before wells are installed. Paper and wood decay slowly. Satellite and aircraft surveys can now detect a methane plume over a landfill, often from the working face or damaged cover. When reading a figure, check whether it describes methane generated, collected or emitted. Those are different quantities, and confusing them can hide much of the problem.