JBA flood data supporting insights from S&P Global Sustainable1
Climate change is reshaping flood risk – not just globally, but at the level of individual buildings. For banks, insurers, investors and asset managers, understanding how flood risk could evolve across portfolios over the coming decades is becoming increasingly important.
However, assessing future flood risk starts with understanding flood risk today. Reliable, high-resolution baseline flood hazard information provides the foundation upon which future climate risk analytics are built.
To support asset-level climate risk analysis, S&P Global Sustainable1 integrated JBA Risk Management’s Global Flood Maps and defended areas into its Climanomics® platform.
Selected for its global consistency, high quality and seamless integration with S&P Global’s workflows, JBA’s datasets provide the foundation for assessing how flood hazard and financial risk may evolve under different climate scenarios.
As part of this work, S&P Global conducted detailed analyses of future flood risk in two cities around the world: Sacramento, California; and Frankfurt, Germany. Here, we explore the findings from Sacramento and what they reveal about the importance of high-resolution flood data to assess the potential impact of climate change.
Why high-resolution flood data matters
At 30 m resolution across 99.98% of the world’s landmass, JBA’s River and Surface Water Global Flood Maps combine detailed terrain and land use information, hydraulic modelling, and historical river and rainfall observations to capture flood extents and depths at a granular scale (Figure 1). Importantly, the data also includes local and regional flood defence systems and the standards of protection they currently provide.
This level of detail enables users to assess how future flood exposure and financial impacts may vary between individual buildings, infrastructure assets and wider portfolios under different climate scenarios.
Sacramento: how future flood risk could evolve
Sacramento, California’s state capital, sits at the confluence of the Sacramento and American rivers, making it one of the most vulnerable cities to flooding in the United States.
S&P Global Sustainable1’s Climanomics® platform was used to analyse approximately 89,000 single-family homes across the city to assess how flood hazard and associated property damage could evolve under the SSP2-4.5 climate scenario, an emissions pathway in which global average temperatures are projected to rise by around 2.7°C by 2100.
S&P Global’s analysis identified that more than 5,000 properties are currently exposed to flooding during a 20-year flood event. By the 2040s, that number is projected to increase to 5,641 properties, particularly in areas outside the city’s levee system.
More significantly, the research suggests that Sacramento’s current levee system, built to defend against a 100-year flood event, could become less effective over time. In the 2030s, a flood with a present-day 100-year return period is projected to potentially overtop the city’s levee system, potentially exposing around 19,000 homes to flood depths exceeding 0.5 m.
These changes have important financial implications. Flood depths exceeding 0.5 m can cause significant damage to ground floor electrical, communication and ventilation systems, substantially increasing repair costs and disruption.
Using Climanomics®, S&P Global estimated potential property damage of:
- Approximately $378 million during a 20-year flood event in the 2030s
- Approximately $3.6 billion during a 100-year flood event in the 2030s (Figure 2)
The analysis also suggests that more than 10,000 properties could face damage exceeding $100,000 during a future 100-year flood event in the 2030s compared with present-day conditions.
What this means for financial institutions
For lenders, insurers and investors, the findings highlight how future flood risk may affect both asset values and financial resilience.
For example, in mortgage lending, severe flood damage can create situations where repair costs exceed the value of a property. This increases the risk of negative equity and borrower default, particularly where households also face loss of income or prolonged disruption following a flood event.
The Sacramento case study demonstrates the importance of the underlying flood data in quantifying financial risk. Asset-level analysis and more informed decision-making depend on having high-resolution flood hazard information capable of estimating how risk varies between individual properties. Without this level of detail, important at-risk assets may be missed or obscured by low-resolution data.
Understanding risk across multiple futures
Physical climate risks are influenced not only by future emissions pathways, but also by investment in flood defences, urban development and changes in the built environment.
While S&P Global’s Sacramento analysis focuses on how future flood hazard and financial impacts may evolve under one climate scenario, organisations often need to understand how risk changes across a range of plausible futures.
JBA's Climate Risk Analytics and Catastrophe Modelling capabilities support this type of scenario analysis. This includes global climate change flood maps for river, surface water and coastal flooding, alongside location-specific flood risk indicators that can be used in regulatory reporting, resilience planning and portfolio analyses.
Beyond hazard metrics, JBA's catastrophe models enable organisations to explore how future financial losses may change under different climate pathways, different hypothetical extreme flood events, changing exposure attributes and alternative vulnerability assumptions.
Climate risk is becoming increasingly embedded within financial regulation, disclosure frameworks and strategic planning, which means the ability to test multiple scenarios and understand their implications will become increasingly important. The Sacramento analysis illustrates how climate change can alter not only flood depths, but the effectiveness of existing flood defences and the financial losses associated with exposed assets. Looking across a wider range of scenarios can help organisations better understand uncertainty, assess resilience and make more informed long-term decisions.