Climate change influences are likely to increase the impact of flooding over the near and medium term

Guy Carpenter has launched a fully probabilistic Indonesia Flood Model. The model provides countrywide coverage and enables insurers to assess their exposure to floods, the most frequently occurring natural peril in the country.

Indonesia suffers from very regular flooding,” said Dr David Maréchal, lead hydrologist at Guy Carpenter. “This is driven by natural causes such as high-intensity seasonal rainfall, and man-made influences such as increasing urban density in flood plains and deforestation. We expect to see increased impact from flooding over the near and medium term due to climate change influences.”

The new model covers the whole of Indonesia, replacing the reinsurance broker’s previous Jakarta-only model, and includes the proposed area for the new capital city in East Kalimantan. 

The model is based on a 10,000-year stochastic catalogue simulating both fluvial (riverine) and pluvial (rainfall) flooding. The fluvial component of the hazard was developed using hydrological and hydraulic modeling to simulate rainfall and 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.

Offering enhanced flexibility, the model can produce event-loss tables, occurrence exceedance probability curves, and average annual losses at virtually any level of aggregation. It is powered by the Oasis Loss Modelling Framework (Oasis LMF), an open-source catastrophe modeling platform designed and built by the (re)insurance industry. 

Tony Gallagher, CEO for the Asia-Pacific Region at Guy Carpenter, added: “Flooding impacts thousands of people in Indonesia every year, yet the country faces a significant insurance gap which has severe implications for its economic resilience. Our industry is working to address climate change, with flood being particularly impacted in Indonesia and other countries in Asia.”