Globally, rising sea levels can be attributed to the melting of ice sheets and mountain glaciers on top of the warming of oceans leading to increased volume. Coastal erosion and flooding are one of the major consequences of rising sea levels. The coast of Selangor and Batu Pahat has witnessed severe coastal erosion with a total of 1878.5 hectares and 415.47 hectares respectively. In Johor the damages are estimated at RM 0.35 billion worth of infrastructure and RM 2.4 billion of economic losses.  Thus, the potential sea level rise, which is expected to be higher in Malaysia due to its climate and topography, is expected to cause immense loss of development, agricultural land, forests, marine habitats and ecosystems particularly in low-lying areas of Malaysia. Climate models project that as early as 2040 all of Malaysia’s mangrove forests will be underwater while by 2060 industrial zones will be affected if the sea level rise in 2100 was up to 1 m. 
The Study of the Impact of Climate Change on Sea Level Rise in Malaysia was carried out in 2010 by the National Hydraulic Research Institute of Malaysia (NAHRIM), to project sea level rise in the Malaysian coast for the year 2100 using linear trend analysis and satellite altimetry data (1993-2010) as values for 49 simulations of 7 Coupled Atmospheric-Oceanic General Circulation Model (AOCGM). The study observed mean sea level rise along the Malaysian coast is between 2.7 – 7.0 mm/year.
In the year 2100, Peninsular Malaysia, Sabah and Sarawak sea level rise is projected to be at 0.25 – 0.5m, 0.69 – 1.06 m, and 0.43-0.64m respectively. The highest sea level rise is projected to occur at the northeast and northwest regions in Peninsular Malaysia and at north and east sectors of Sabah in Sabah–Sarawak coastline. NAHRIM later projected in 2017 based on 1993-2015 data that Peninsular Malaysia will experience sea level rise of 0.67 – 0.71 m (10.5-10.9 mm/year) and in Sabah and Sarawak 0.71-0.74m (10.9-11.1mm/year). 
Meanwhile other studies project different rates of sea level rise due to the El Niño event which occurred in 2015 somewhat reduced the rate of sea level over Malaysian seas. One study puts the rate of rise over the period of 1993-2015 at around 3.3 mm per year for East Malaysia and 5.0 mm per year in Peninsular Malaysia with a mean rising rate at 4.2 mm/year.
Centre for Governance and Political Studies (Cent-GPS) posted a viral twitter thread based on Kulp and Strauss’ article “New elevation data triple estimates of global vulnerability to sea-level rise and coastal flooding”. Using CoastalDEM, the same digital elevation model used in the research, CENT-GPS stated that 9 major states will be affected and have parts of land below sea level by 2050, including predictions such as Alor Setar would be turned into an island while Parti Buntar and Taiping will be underwater. The National Hydraulic Research Institute of Malaysia (NAHRIM) has put out a media statement regarding Cent-GPS’ findings stating “Please do note that the analysis method used in the study [by Kulp and Strauss] is only suitable for general assessment at the global level and does not reflect coastal flooding conditions in Malaysia.”
Current Impact on Malaysia’s Coastal communities
Climate model projections also predict that agricultural lands will also be heavily affected. A study’s findings note that palm oil production will decrease by 2%, 4%, and 8% due to sea level rise of 0.5, 1, and 2 respectively. Malaysia is also projected to lose its 7000 km2 land area if no mitigation measures are taken.  Malaysia is also estimated to lose an average RM 100 million per year (conservative estimate) due to flooding.  One study estimates that potentially 7-48 million people in the Indonesia-Malaysia oceans will be displaced due to the primary and secondary effects of sea level rise which are the loss of coastal habitat and the impacts of the loss of marine biodiversity respectively .
Although the social impact of the many coastal communities in Malaysia is under-researched, such communities have already begun to feel the effects of the rising sea levels on top of extreme rainfall and weather affecting marine ecosystems. Dr Serina Rahman, a visiting fellow at the ISEAS-Yusof Ishak Institute, states that “climate change will have devastating impacts on coastal communities across Southeast Asia, especially fishing communities.” This is because “not only will sea level rise affect their homes and the subsistence crops that many depend on, but it will also affect their ability to head out to sea.”
According to Dr. Rahman, such communities have witnessed “more frequent extreme weather events, stronger winds, changes of tides, currents and water temperatures all have a direct impact on their ability to head out to sea and the availability of fisheries species. This then affects their livelihoods, not to mention the severely increased risks to life and dangers they face while trying to bring home their catch.”. Nevertheless, as coastal communities are increasingly affected by the effects of climate change and in particular sea level rise, they have also begun to adapt and mitigate such risks such as building higher house pillars and groyne protection structures in Klang, Kuala Langat, Cherating and Kota Kinabalu. Hence, communities possess local environmental knowledge and have developed early warning systems that can be complemented with government flood and disaster risk reduction.
 Ehsan, Sofia, Rawshan Ara Begum, Nor Ghani Md Nor, and Khairul Nizam Abdul Maulud. “Current and potential impacts of sea level rise in the coastal areas of Malaysia.” In IOP Conference Series: Earth and Environmental Science, vol. 228, no. 1, p. 012023. IOP Publishing, 2019.  Hamid, Amalina Izzati Abdul, Ami Hassan Md Din, Cheinway Hwang, Nur Fadila Khalid, Astina Tugi, and Kamaludin Mohd Omar. “Contemporary sea level rise rates around Malaysia: Altimeter data optimization for assessing coastal impact.” Journal of Asian Earth Sciences 166 (2018): 247-259, p. 258.  Awang, Aslinda and Mohd Radzi bin Abd. Hamid, “Sea level rise in Malaysia” Hydrolink 2 (2013): 47-49, p. 47.  Baharuddin, M.K. Climate Change – Its effects on the agricultural sector in Malaysia. National Seminar on Socio-Economic Impacts of Extreme Weather and Climate Change, 21-22 June, 2007.  Wetzel, Florian T., W. Daniel Kissling, Helmut Beissmann, and Dustin J. Penn. “Future climate change driven sea‐level rise: secondary consequences from human displacement for island biodiversity.” Global Change Biology 18, no. 9 (2012): 2707-2719, p. 2714.