SYNOPSIS

Malaysia’s water resources sector is currently plagued by three major issues, namely water excess, water shortage, and water pollution. Behind these issues looms the threat of climate change. Climate change and variability, together with non-climatic drivers such as population increase, intensive land development, and loss of forests, have physical impacts on the hydrological cycle especially in recent decades. Increased frequency of floods, increased catchment erosion and siltation, inadequate environmental flows, increased pollution and deterioration of river water quality, and limited water supply are among some climate change impacts that threaten the sustainability of our water resources. The impacts can be modelled and projected by downscaling approach using the output from Global Circulation Models (GCMs). Adopting the dynamic downscaling approach, NAHRIM has completed the development of the regional hydrologic-atmospheric model of Peninsular Malaysia (RegHCM-PM 2006), and Sabah and Sarawak (RegHCM-SS 2010), as well as Regional Climate Model (RCM) for Peninsular Malaysia, Sabah and Sarawak using PRECIS in 2010. Annual daily mean temperature projection from RegHCM model for the whole Malaysia from year 2020 up to 2099 shows the increase of surface temperature from 0.5°C to 3.5°C. The simulated future maximum monthly rainfall for the whole peninsular is expected to increase by as much as 12% compared to the simulated historical. As for Sabah and Sarawak, the maximum monthly rainfall is projected to increase at 5.1% and 8% respectively during mid-21st century. However, although the dry and wet years can be discerned throughout the century, no clear trend can be seen observed over Sarawak state. The long-term trend of annual rainfall is also not pronounced since the inter-annual precipitation variability is quite large for Sabah and Sarawak. The model output in terms of projected climatic parameters such as rainfall, temperature and evapotranspiration is very essential for the quantification of the potential climate change impacts on water resources and water resources management. This leads to the necessity for developing engineering approaches for climate change adaptation particularly to bridge and translate the gap between scientific knowledge and engineering practices in water sector, for instance reviewing of water system management and plans, reviewing design standards for water related risk management in all new infrastructures including water control structures, transportation structures and electrical, water and waste amenities to incorporate climate change factor, and complementing structural approaches with non-structural approaches such as improved rainfall and flood forecasting, disaster warning system and flood hazard mapping as part of a coordinated disaster prevention and management plan. Above all, these information need to be conveyed to policy makers or planners to be implemented or enforced in the country. These are all part of adaptation and mitigation measures to cushion climate change impact.


BIODATA OF SPEAKER

Ir. Hj. Ahmad Jamalluddin b. Shaaban currently is a Director General of NAHRIM (Mac 2009 to present). He is responsible for conducting research and consultancy services in water resources and hydrologic engineering sector focussing on impact of climate change on hydrology and water resources including adaptation; rainwater utilisation and management systems; drought management; irrigation and drainage; hydraulic modelling; estimation of probable maximum precipitation; and reservoir design and operation.