How does composting help global warming?

Answer 1

Composting organic material reduces GHG emissions compared to landfilling with energy recovery systems. According to the most conservative estimates, which fail to account for many (if not most) GHG-reducing benefits of composting, California could reduce its GHG emissions by one million MTCO2E by composting just 30% of the foodwaste that is currently disposed. This is equivalent to the carbon sequestered by 26 million tree seedlings grown for 10 years.

When waste is sent to landfill, air cannot get to the organic waste. As the waste decomposes, it forms methane, a harmful greenhouse gas, which damages the Earth's atmosphere. However, when this same waste is composted above ground at home, oxygen helps the waste to decompose aerobically. This means no methane is produced, reducing global warming. -greenquestionsandanswers.com

Compost can significantly reduce agricultural energy demand. Plants grown in compost-rich soil require less irrigation because of the increased infiltration and storage capacity of root systems and the reduction of water runoff, evaporation, and water usage by weeds. Research has shown that the application of compost can reduce the need for irrigation by 30-70%. Given that approximately 8% of the electricity generated in the state is used to run California’s massive water supply infrastructure, a substantial decrease in water consumption would significantly reduce energy consumption.

Composting provides nutrient-rich soils, which multiple studies have shown results in greater carbon storage in crop biomass.

The application of compost results in a reduced need for GHG producing petroleum-based chemical fertilizer, pesticides, herbicides, and additives. These chemicals are carbon-intensive in their production and emit large quantities of global warming pollutants during application and as they decompose in the soil. The use of compost can reduce the need for fertilizers for vegetable crops by 33-66%.

The application of compost greatly increases the amount of carbon sequestered in soil. Experimental studies have shown that increased carbon sequestration in soil from composting application was 6 to 40 tons of carbon per hectare. - cawrecycles.org