The combined impacts of climate change and rapid urbanisation are aggravating flood risk in the Philippines - Guy Carpenter

Reinsurance broker Guy Carpenter has launched a probabilistic flood model for the Philippines. The model is powered by the open source Oasis Loss Modelling Framework and allows insurers to assess flood exposure, one of the most frequently occurring natural hazards in the region.

It is based on a 10,000-year stochastic catalogue simulating both fluvial (riverine) and pluvial (rainfall) flooding, including the impact of typhoon-induced precipitation. The fluvial component of the hazard was developed using hydrological and hydraulic modeling to simulate river discharges across the river network in the country. Pluvial flooding is simulated using an in-house methodology accounting for local climate conditions, soil type, land use, and topography.

It can produce event-loss tables, occurrence exceedance probability curves, and average annual losses at virtually any level of aggregation. 

Bengt Johnsen, head of South East Asia and Korea Region, Guy Carpenter, said: “The Philippines has a long history of devastating flood events, and the combined impacts of climate change and rapid urbanisation are aggravating the problem. Our model provides clients with… capabilities to quantify flood risk and make informed business decisions, both for internal risk management purposes and for the placement of reinsurance.”

The model was developed by incorporating data from a number of public and private institutions, including JBA, Intermap and the European Space Agency. It features up-to-date flood defense information resulting from a comprehensive survey of current mitigation projects, including those sponsored by the Japanese International Cooperation Agency (JICA).

The built environment was created by incorporating data from various sources, including satellite products and Guy Carpenter’s proprietary Industrial Park Database. The vulnerability component of the model is based on a compendium of empirical vulnerability functions from scientific literature developed in collaboration with the German Research Centre for Geosciences and presented in a peer-reviewed academic paper on the latest advances in flood vulnerability modeling. The vulnerability component was further calibrated using a database of historical losses in the Philippines.