Methane, carbonaceous and sulfate aerosols, and tropospheric ozone are short-lived air pollutants that influence the Earth's climate and variously damage human and ecosystem health. These air pollutants, collectively known as short-lived climate pollutants (SLCPs), and their precursors share many of the same anthropogenic emission sources. The near-term climate impact of SLCPs is species dependent – some pollutants warm the climate, while others have a cooling impact. In a 2011 report , UNEP & WMO identified a set of priority measures aimed at SLCP reductions at the global scale that would simultaneously achieve benefits for both air quality and climate. This project assesses the regional importance of SLCP mitigation measures in China using updated emission projections. An emission reduction scenario incorporating the most-promising SLCP emission reduction measures in China will be used in planned global chemistry-climate model runs.
An updated emission scenario for China was built from components existing in the GAINS database, including an energy pathway based on regional-level data. All technological measures available in the GAINS database were screened for their potential to simultaneously mitigate near-term warming and provide human health and crop co-benefits through reducing emissions of the short-lived climate pollutants. East Asia-specific emission metrics were used to calculate CO2-equivalent emission reductions in 2030 for each co-emitted pollutant for all available pollution control measures. The potential climate impacts from all co-emitted pollutants were summed for each technology, and the emission reduction measures were ranked according to their overall potential climate impact. Potential benefits from air quality improvements were calculated using the GAINS model.
The screening process identified over 100 measures in the GAINS database that would result in co-benefits for air quality and near-term climate protection if implemented by 2030. Of the total CO2-equivalent emission reductions possible in 2030 from implementation of all of the identified measures, roughly 45% of the reductions can be attained by control of methane emissions from coal mining. Introduction of new, cleaner-burning residential cooking stoves has high potential for both reducing warming emissions and limiting damage to human and crop health.
Like the global study, the regional study identified both methane and black carbon abatement measures as being of high priority for limiting near-term warming. In China, methane-reduction measures were found to have the highest potential for mitigating warming. Implementation of the SLCP-reduction measures with the highest potential climate impact can provide co-benefits in the form of avoided damage to human and crop health.
 UNEP/WMO 2011. Integrated Assessment of Black Carbon and Tropospheric Ozone. United Nations Environment Programme (UNEP), Nairobi, Kenya.
Kandice Harper, of the Yale School of Forestry & Environmental Studies, is a US citizen. She was funded by IIASA's United States National Member Organization and worked in the Mitigation of Air Pollution and Greenhouse Gases (MAG) Program during the YSSP.
Please note these Proceedings have received limited or no review from supervisors and IIASA program directors, and the views and results expressed therein do not necessarily represent IIASA, its National Member Organizations, or other organizations supporting the work.
Last edited: 19 August 2015
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