Composting: A green house gas mitigation measure

Background information

Composting of any type of compostable waste reduces green house gases (GHGs) emission over any other management option. Compostable organics mainly produced by agriculture, horticulture, residential and other allied sectors, make up 30 to 50% of India’s overall waste stream. Contributing millions and billions tons of wastes annually to feed various methods of waste treatments like direct burning, land filling etc. Through direct burning process, it releases large amount of co2 to the atmosphere, one of the main green house gas, in addition, through land fillings, the waste materials undergoes anaerobic decomposition and produce significant quantity of methane, an another important green house gas, up to 80% of which is not captured by land fill gas system. Composting on the other hand, is a fundamentally aerobic process and well managed compost facilities do not produce any methane. Composting offers an environmentally superior alternative to land filling organics that eliminates methane production, provide a series of economic and environmental co-benefits and has substantial impact on green house gas reduction.

Important benefits of composting as mitigation measure for green house gases

  • Composting organic materials reduces GHG emissions compared to landfiling with energy recovery systems. According to the most conservative estimates, which fail to account for many (if not most) GHG- reducing benefits of composting for example California (USA), composting could reduce its GHG emissions by one million MTCO2E by composting just 30% of the food waste that is currently disposed. This equivalent to the carbon sequestered by 26 million tree seedlings grown for 10 years.
  • Compost can significantly reduce agricultural energy demand. Plants grown in compost-rich soil require less irrigation because of the increased infiltration and storage of root systems and the reduction of water runoff, evaporation and water usage by weeds.
  • 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 fertilizer for vegetable crops by 33-66%
  • The application of compost greatly increase 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.

Feedback of Dr.Raja naika, Professor, Dept of Applied Botany, Kuvempu University, Shankaraghatta, Shimogga.

Submitted to KSPCB, Karnataka.


Disclaimer: The views expressed here are of the author and not of KSPCB. The article is published only in the interest of a public understanding of the issues involving Climate Change and should not be construed as the policy guidelines of KSPCB.