Is incineration better or worse than landfill?
Generally better than landfill for the same waste, and worse than not producing the waste at all — which sounds like a dodge and is the actual finding of most life cycle assessments.
Where landfill genuinely loses. Organic waste decomposing without oxygen produces methane, a greenhouse gas far more potent than CO₂ over the short term. Modern sites capture some of it, and capture rates are imperfect and debated. Landfill also occupies land permanently, produces leachate requiring management indefinitely, and defers the problem rather than resolving it.
What incineration does. Modern energy-from-waste plants burn waste at high temperature, generating electricity and sometimes heat for district networks, reducing volume by around 90%.
Its genuine drawbacks:
It still emits CO₂, and because a large fraction of residual waste is plastic — which is fossil-derived — the carbon intensity of the electricity produced can be worse than the grid average as grids decarbonise. This is the argument that has changed most in recent years: incineration looked good against a coal-heavy grid and looks much less good against a renewable one.
Air emissions of particulates, dioxins, nitrogen oxides and heavy metals, tightly regulated and monitored — and a persistent source of local objection.
Bottom ash and fly ash, the latter classified as hazardous and requiring specialist disposal.
The lock-in problem, which is the strongest objection. Plants are expensive and are financed on long-term contracts guaranteeing a supply of waste. That creates an institutional interest in continued waste generation and can actively discourage recycling — several authorities have found themselves contractually obliged to supply tonnage.
Where both sit in the hierarchy: prevention, reuse, recycling, recovery (including incineration with energy), then disposal. Both are near the bottom by design.
What would actually change the picture: less residual waste, better separation so recyclables and organics never reach either route, separate treatment of food waste by anaerobic digestion, and designing products to be recyclable in the first place.