Residents play an educational garbage sorting game during a waste management awareness campaign at a residential community in Dongcheng district of Beijing, capital of China, on May 23 (XINHUA)

The last three years have seen China's policymakers pay increasing attention to the country's waste problem. In 2018, municipal solid waste (MSW) in China reached 228 million tons, an amount which is expected to rise to 409 million tons by 2030 driven on by continued urbanization and economic growth. This swelling volume of garbage poses a threat to both the environment and the climate.

In 2017, China enacted a pilot program of new waste sorting regulations in selected cities, which policymakers are now planning to roll out nationwide. In late April this year, the government approved changes to the Solid Waste Law, highlighting waste sorting and making it a core element of the revised law. As a result, more cities will be adopting the new waste sorting regulations. Innovative Green Development Program (iGDP) estimates that if the regulations are fully implemented, China's greenhouse gas (GHG) emissions will be reduced by 80.82 million tons of carbon dioxide equivalent (CO2e) between 2020 and 2030.

These are positive developments, but China will have to make sure that the regulations are properly implemented.

Waste sorting policy progress

China began implementing its pilot waste sorting regulations across 46 cities in 2017. The regulations divided MSW into four categories: recyclables (plastics, glass, paper), perishables (mainly food waste), hazardous materials, and residual waste. Unlike the previous system—which was composed of just recyclables and residuals—the new regulations emphasize the collection and disposal of perishables, which accounts for approximately 60 percent of MSW and is a major contributor of GHG emissions within the waste sector.

The new waste sorting policy required all 46 pilot cities to develop work plans for waste sorting by March 2018, and set up local waste sorting mechanisms by the end of 2020. At present, all the cities have released new waste management work plans, and 12 have passed local waste sorting legislation. With the passing of the revised Solid Waste Law this year, which comes into effect on September 1, these new and improved waste sorting practices will be rolled out across China's prefecture-level cities. As perishables will be treated separately in this new system, not only will less garbage be sent to landfills or incinerated, GHG emissions from landfills will also be reduced.

Waste sorting and climate change

The application of the new waste sorting policy across more Chinese cities will cut GHG emissions in China's waste sector, particularly methane, which has high global warming potential despite its short lifespan.

As the new waste sorting rules are implemented, we can expect reductions of GHG emissions in two main areas. First is from landfills and incineration, as the separate collection of perishables reduces mixed garbage for landfills or incineration. The second reduction comes from replacing fossil fuels with biogas, as perishables—and particularly food waste—generate a large amount of biogas which can be used for heat and electricity generation in the course of anaerobic digestion.

An iGDP comparison of projected MSW emissions between a business-as-usual (BAU) scenario and a new policy scenario, which assumes national scale-up of all new policies, shows that the new waste sorting policy can reduce GHG emissions by 80.82 million tons of CO2e between 2020 and 2030. This is equal to emissions from 17.46 million passenger vehicles driven for one year.

Implementation is key

China's new waste sorting policy is being applied in pilot cities and can be expected to make an increasing contribution to GHG reductions as the new Solid Waste Law leads to improved practices across the country. However, implementation remains a challenge.

Chinese cities will be required to develop comprehensive waste sorting systems that ensure proper collection and treatment of perishables, but this is a complicated task. Another challenge lies in public trust of the effectiveness of waste sorting. There are concerns that China's insufficient food waste processing capacity is leading to sorted garbage getting mixed again in later stages of processing.

Another way to improve waste management, and thereby reduce GHG emissions, would be to reduce its generation in the first place, especially food waste. This is a policy area that should receive more attention going forward.

The author is a senior analyst at Innovative Green Development Program (iGDP), an independent environmental think tank based in Beijing