Two new studies published this week add to growing evidence that climate change is increasing the frequency and severity of coastal flooding around the world. Researchers found that extreme flood events that historically had only a 1% annual chance of occurring are now roughly 12 times more likely on average. Human-driven climate change alone accounts for approximately a fourfold increase in the likelihood of these events.
The studies examined long-term tide gauge records, climate models, and sea level trends to separate natural influences from human-caused warming. Researchers concluded that while natural variability played a larger role earlier in the 20th century, greenhouse gas emissions have become the dominant driver of rising sea levels since the 1960s. A companion study found climate change contributed to roughly 58% of major coastal flood days between 2000 and 2018 and nearly tripled the number of extreme flood days since the 1970s.
For insurance claims professionals, the findings point to continued growth in coastal flood exposure and potentially higher claim frequency in vulnerable regions. As sea levels rise, even moderate storm surges and high-tide events can produce damaging floods that previously may not have crossed loss thresholds. This increases pressure on catastrophe models, underwriting assumptions, and claims resource planning during coastal weather events.
The research also underscores the importance of infrastructure resilience and mitigation efforts. Experts cited concerns that existing flood protection systems in areas such as New Orleans may not provide adequate protection in coming decades. Adjusters, carriers, and risk managers may increasingly encounter losses tied to aging flood defenses, repetitive-loss properties, and evolving coastal hazards.
The studies arrive as governments and insurers continue evaluating long-term climate risk. For the claims sector, the message is clear: historical flood patterns may no longer be reliable predictors of future losses, particularly in low-lying coastal regions where sea level rise is amplifying storm-related impacts.
