One of the greenhouse gases, which is the cause of climate change and global warming is methane gas (CH4). One of the most significant sources of methane that contributes to emissions globally is landfills (anthropogenic sources). Methane emissions from waste are the result of the anaerobic decomposition of organic matter in waste. The more garbage in the landfill without further treatment can lead to greater methane emissions. The site of this study was a municipal solid waste in Makassar city, named Tamangapa landfill,±15 km from downtown Makassar city. The objectives of this study are to estimate methane emissions in the Tamangapa landfill and estimate methane emissions from the Tamangapa landfill over the next ten years using the 2006 IPCC Waste Model. The results showed that the waste generation in Makassar City, in 2016, was 0.449 kg/person/day with the composition of waste dominated by organic waste. The value of potential methane emissions at TPA Tamangapa Makassar in 2016 is 2.24 Gg/year and the projection in 2026 is 4.968 Gg/year. The mitigation and adaptation efforts that can be recommended are the socialization of 3R techniques (Reduce, Reuse, and Recycle) and construct a sanitary landfill in Makassar city following the mandate of Law No. 18 of 2008.