CHAPTER IIREVIEW OF RELATED LITERATUREMethane (CH4) remains to be one of the top global short-lived climate pollutants (SLCPs) threatening human health, ecosystems, and the economic security of large populations. In 2005, Philippines was ranked 32nd in emitting Methane worldwide and a huge portion of these emissions come from Municipal Solid Waste (MSW). Information on impacts of future policies regarding waste is necessary to correctly address the adverse, imminent effects brought by SLCPs like Methane.Short-Lived Climate PollutantsShort-lived climate pollutants (SLCPs) are substances in the atmosphere with short lifespans, ranging from only a few days to a few decades, which accounts for 40% of current net climate forcing. Aside from being powerful climate forcers (global warming drivers), they are also considered as harmful air pollutants that have a bigger impact on climate change in the near term compared to the long-lived green house gases (GHGs). SLCPs include Black Carbon (BC), Methane (CH4), Tropospheric Ozone (O3), and fluorinated gases (such as hydrofluorocarbons) (Lefevre, 2018). BC has a lifetime of days, O3 has a lifespan of weeks, while the methane’s atmospheric lifetime is twelve years and HFCs’ is 15 years. BC and O3 alters rainfall patterns in the lower atmosphere at a regional level. BC and co-pollutants compose mostly the particulate matter 2.5, which is one of the primary environmental causes of illnesses and premature death. An estimation of 3.5 and 3.2 million people die prematurely annually because of indoor and outdoor pollution. Tropospheric Ozone, which is mainly formed from CH4, negatively affects public health and induces crop loss (CCAC, 2018). Reduction of SLCPs provide near-term benefits but a larger advantage in the long run is having carbon-cycle responses and reduced sea-level rise (Lefevre, 2018).Methane Out of the 40% current net climate forcing worldwide due to SLCPs, 20% comes from Methane emissions. Methane is created due to natural processes like decomposition of plant and animal waste and due to many man-made activities, such as coal mines, natural gas and oil systems, and landfills (CCAC, 2018). Currently, 60% of methane in the atmosphere is mainly man-made. In the Philippines, the sources of 18 percent of its methane emissions, 7.1 MMTCO2E, are agriculture (manure management), coal mines, and municipal solid waste (Global Methane Initiative, 2018). CH4 is also considered a GHG with a high global warming potential (ARB-CEPA, 2017). It poses indirect negative effects on human health and ecosystems because it is changed to another form when in lower atmosphere – that is the tropospheric zone, which is a common air pollutant causing health complications and premature deaths (CCAC, 2018). Agriculture, fossil fuel production and distribution, municipal waste and wastewater management are found to compose 93% of worldwide man-made methane emissions in the year 2005. UNEP & WMO (2011) affirms in their projected trends that anthropogenic methane emissions will likely increase by 25% in 2030 when no mitigation action is still taken.Municipal Solid WasteDefine, Generation, history, WACSLITERATURE CITEDAir Resources Board, California Environmental Protection Agency March 2017. Short-lived Climate Pollutant Reduction Strategy from https://www.arb.ca.gov/cc/shortlived/meetings/03142017/final_slcp_report.pdf Global Methane Initiative 2018. Philippines from https://www.globalmethane.org/partners/country.aspx?country=philippines Climate and Clean Air Coalition 2018. Methane http://www.ccacoalition.org/en/slcps/methaneClimate and Clean Air Coalition 2018. Short-lived Climate Pollutants: Response to mitigation efforts from http://www.ccacoalition.org/en/science-resourcesElsa Lefevre 10 April 2018. National Action and Planning to Reduce Short-Lived Climate Pollutants from CCAC magazine (check ppt).