CH4 mitigation potentials from China landfills and related environmental co-benefits

Abstract

China's CH₄ emissions from 1955 existing (old) and 495 planned (new) landfills are estimated and projected by adopting a bottom-up method, targeting a 2012 baseline year and a 2030 projected target year. Nine key CH₄ mitigation measures are proposed for the CH₄ mitigation assessment from landfills. Approximately 0.66 million metric tons (Mt) of CH₄ and 1.14 Mt of CH₄ will be released, respectively, from new and existing landfills under a 2030 business-as-usual (BAU) scenario, which is 23.5% lower than a U.S. Environmental Protection Agency estimation. It is estimated that 0.60 and 0.97 Mt of CH₄ can be reduced under new policies (NP) and low-carbon (LC) policy scenarios, respectively. The combined biocover and landfill gas collection and flaring system is the most promising mitigation measure, while mechanical biological treatment and mineral landfill also contribute substantially to CH₄ reduction. The odor-affected population under NP and LC scenarios will decrease by 39.5 and 64.2%, respectively, when compared to the 2030 BAU scenario. The LC scenario is a recommended policy for meeting China's nationally determined contribution targets and reducing the not-in-my-backyard impact due to this policy's significant reduction of CH₄ emissions.

Fig. 1. A schematic diagram of the analysis process.

The BAU, NP, and LC represent three scenarios in 2030. FOD, first-order decay.

Fig. 2. Landfill CH₄ emissions (Mt) and populations (million persons) affected by malodorous emissions in 2012 and under three 2030 scenarios.

The BAU, NP, and LC represent three scenarios in 2030.

Fig. 3. Geographic spatial patterns for landfill CH₄ emissions in 2012 and three 2030 scenarios.

The BAU, NP, and LC represent three scenarios in 2030.

Fig. 4. Frequency distributions of individual landfill CH₄ emissions for different geographic regions for the year 2012 and three 2030 scenarios.

The BAU, NP, and LC represent three scenarios in 2030. The violin plots show the distributions of landfill emissions, with each side representing the same value. The box plot inside the distribution indicates the first, second (the median), and third quartiles of the distribution. The number of landfills in each region for each time period are parenthetically represented.