Composting is a practical climate change mitigation and adaptation strategy that can be adopted at the individual level. As a climate action strategy, composting has the potential to divert a large portion of organic materials from landfills, while returning these nutrients to the soil.
Composting offers a solution for the sustainable disposal of organic waste, including food waste. This is linked to climate change because, when taking into account the greenhouse gas (GHG) emissions that are generated during food production, food waste accounts for 8-10% of human GHG emissions each year (2021 UNEP Food Waste Index).
The climate impact of food waste is exacerbated by waste outcomes with high GHG emissions, specifically landfilling. Food scraps in landfills generate methane, a potent greenhouse gas. In fact, landfills make up the third largest source of human-related methane emissions.
Whereas landfills are a source of GHG emissions, composting can reduce GHG levels in the atmosphere by improving soil’s ability to sequester carbon. This is because when soil is amended with compost, more carbon can be stored in the soil instead of being released into the atmosphere as CO2.
Compost application also enhances soil health by reintroducing nutrients to the soil and improving its water-holding capacity. By returning nutrients from organic materials to the soil, composting promotes a closed-loop system that produces healthier plant growth and more nutritious crops. Compost also improves soil’s capacity for water retention and makes it more resilient to flooding and droughts, which are becoming increasingly common in the face of climate change.