Climate change is no longer a peripheral scenario exercise for insurers - it is a present-day driver of claims experience, capital requirements, regulatory scrutiny and strategic positioning. Flooding, subsidence, windstorm and wildfire losses are trending upward across many geographies, and the UK market faces the added complexity of dense coastal exposure and ageing housing stock. For an industry whose core competence is pricing risk, climate change poses a distinctive challenge: the past is losing its authority as a guide to the future.
Physical risk: non-stationarity breaks the historical record
Actuarial pricing and catastrophe modelling have traditionally leaned on historical loss experience. A warming climate undermines that foundation. Sea level rise amplifies storm surge; a warmer atmosphere holds more moisture, intensifying rainfall and flood; heat and drought cycles drive subsidence claims on clay soils - a particularly British problem; and wildfire seasons lengthen in regions once considered low hazard. The statistical term is non-stationarity: the distribution generating losses is shifting under our feet. Models calibrated to the last forty years quietly misprice the next ten.
Transition risk: the other side of the balance sheet
Climate risk is not only about claims. Insurers hold vast investment portfolios exposed to the transition to a low-carbon economy - repricing of carbon-intensive sectors, stranded assets, and policy shifts that alter asset values. Liability risk adds a third channel: directors and officers, professional indemnity and general liability lines all face claims connected to climate disclosure, greenwashing and failure-to-adapt allegations.
The regulatory agenda
UK regulators moved early. The PRA expects insurers to embed climate risk in governance, risk management, scenario analysis and disclosure, and climate scenario exercises have tested the sector's resilience against orderly, disorderly and hot-house pathways. The direction of travel is clear: climate risk management is now a supervisory expectation, not a voluntary initiative, and boards are expected to understand and own the results of scenario analysis rather than delegate them to a sustainability function.
What leading insurers are doing
Best practice is converging on several fronts. Catastrophe models are being adjusted or conditioned on forward-looking climate science rather than purely historical calibration, with vendors and internal teams developing climate-conditioned event sets. Underwriting strategies increasingly incorporate resilience: premium credits for flood defences, building standards and defensible space. Portfolio steering limits aggregate exposure growth in high-hazard zones. On the asset side, net-zero commitments are being translated into measurable interim targets and engagement strategies. And product innovation - parametric covers, community-based schemes and public-private partnerships such as Flood Re in the UK - is expanding insurability where traditional indemnity products retreat.
The insurability question
The hardest strategic issue is availability. Where risk-based pricing makes cover unaffordable, markets fail politically as well as commercially, inviting intervention. Insurers that engage constructively - sharing risk insight, supporting adaptation investment, designing affordable products - will shape those interventions rather than be shaped by them.
Conclusion
Climate change rewrites the assumptions beneath insurance. The winners will treat climate not as a reporting obligation but as a core modelling, underwriting and capital question - building forward-looking analytics and products for a world where the new normal keeps moving.