Modelling Climate Change Impacts on Water Balance

Dr. Edwin A. Combalicer, Assistant Professor, Institute of Renewable Natural Resources, College of Forestry and Natural Resources, UPLB
25 October 2011
Special Seminar; In cooperation with Gamma Sigma Delta-Honor Society of Agriculture (GSD-HSA)

More hydrologic events such as rainfall and high evaporation rates are expected to occur in and around Mount Makiling Forest Watershed. This may leave profound impacts on the agricultural development, livelihood, and economic and biodiversity sustainability of the ecosystem.

This is according to Dr. Edwin A. Combalicer of the University of the Philippines Los BañosCollege of Forestry and Natural Resources in his presentation on Modelling Climate Change Impacts on Water Balance as part of SEARCA’s Agricultural and Development Seminar Series.

Sustainability of forest watersheds is necessary to attain ecological balance and good quality source of water to sustain both human life and wildlife. The study conducted by Dr. Combalicer revealed that the growing effects of climate change profoundly affect the water balance of Mount Makiling Forest Watershed, leaving deep impacts on its hydrologic processes. These impacts were evaluated by downscalinglarge scale climate information through the use of the Statistical Downscaling Model (SDSM).

Dr. Combalicer generated two scenarios using the Third Generation Coupled Global Climate Model (CGCM3). The first scenario A1B envisions a future world of technological change and rapid economic growth and development. The second scenario A2, on the other hand, describes a heterogeneous world with high population growth, low technological change, and economic development.

By incorporating the downscaled climate change impacts as inputs to hydrologic modelling, his study was able to predict the changes in precipitation and minimum temperature given the two scenarios in the next 100 years.

The simulated results showed that in the future, dry seasons would be drier, while wet seasons would be wetter. “The distribution of the hydrologic processes will be greatly affected by changing climate,” Dr. Combalicer said, “the study categorically predicted the likelihood of occurrences of longer dry season and extreme rainfalls.” He furthered that the A2 scenario’s findings exhibited more damaging impacts of climate change in the future.

As of now, plans to establish watershed instrumentation for baseline information generation following standardized instrumentation techniques are already laid out. This in turn will be used to develop storm hydrographs immediately after typhoons and heavy rain events.

Results of Dr. Combalicer’s study proved the need for better policies regarding climate change and disaster risk reduction management. (DAMDomingo)