“Climate Projection until 2100 in Malaysia and Objective Analysis Techniques.”

The ability to transform complex atmospheric dynamics into accurate, localized climate projections and actionable climate-based solutions represents a critical measure of Malaysia’s climate resilience. Recent climate observations indicate a significant shift in climate patterns, characterized by an increasing frequency and intensity of extreme weather events across Malaysia. Concurrently, the country has experienced a steady rise in greenhouse gas (GHG) concentrations, including carbon dioxide (CO₂), methane (CH₄), and nitrous oxide (N₂O), which are the primary drivers of rising temperature anomalies. Additionally, to assess the impact of these greenhouse gases (GHGs) on future climate conditions, experiments using Global Climate Models (GCMs), dynamically downscaled through Regional Climate Models (RCMs), were conducted for Malaysia. Objective analysis techniques were applied to select suitable GCMs and to validate the performance of the RCM simulations. Under the high-emission SSP5-8.5 scenario (2080–2099), Malaysia is projected to experience a substantial increase in temperature relative to the baseline period. Projections indicate that mean daily maximum temperatures will increase by approximately +4.1°C in Peninsular Malaysia and up to +4.5°C in Sarawak. In addition, rising temperatures are the primary drivers of heatwave-related health risks, which are further intensified by the Urban Heat Island (UHI) effect in areas such as Greater Kuala Lumpur (GKL), where heat intensity is most pronounced at night but reaches its peak during the day. During heatwave events, the maximum heat load in GKL at noon can be up to 2.3°C higher than on non-heatwave days. Moreover, because a warmer atmosphere can hold approximately 7% more moisture per degree Celsius, Malaysia is projected to experience up to a 40% increase in daily rainfall extremes by the end of the century. This intensified precipitation, coupled with urbanization and land-use changes that reduce ground absorption, substantially elevates the risk of flash floods in major urban centres.