Will Banks and Kemal Erçevik
When excessive climate hits, households usually flip to insurers to cushion the monetary blow. However rising temperatures and larger publicity in high-risk areas may check the insurance coverage sector’s capability to soak up such losses. Because the Monetary Coverage Committee has highlighted, local weather change may create insurance coverage safety gaps, leaving households susceptible and shifting dangers throughout the monetary system. Now we have constructed a mannequin to estimate potential safety gaps, discovering that – beneath conservative assumptions – the share of UK mortgagors uninsured may improve from 5% immediately to round 7%–10% in 2050, or as much as 16% following a extreme flood occasion. Whereas this may have substantial welfare implications, our mannequin suggests the combination influence on lenders can be small in comparison with earlier monetary crises.
How may insurance coverage safety gaps come up?
Within the UK, most mortgagors have mixed buildings and contents insurance coverage masking flooding. That’s partially because of Flood Re, which subsidises insurance coverage for prime flood-risk households.
However that would change as temperatures rise. Beneath a really conservative emissions pathway situation – consultant focus pathway 8.5 – floods are prone to develop into considerably extra frequent and extreme.
Alongside the deliberate finish of Flood Re in 2039, this might push up insurance coverage prices and cut back protection. Imperfect data or restricted urge for food to underwrite the best dangers may lead insurers to withdraw from sure areas – as seen in California following current wildfires.
Decrease insurance coverage protection may lead dangers to shift throughout the financial system and monetary system. Home costs may fall if potential consumers begin to consider greater insurance coverage prices. Banks may face greater losses on mortgages as collateral values fall, or if debtors develop into extra prone to default because of greater premia or uninsured flood damages. Now we have constructed a mannequin which captures these dynamics in a stylised approach (Determine A).
Determine A: A stylised determine of our insurance coverage safety gaps mannequin
First, we mix a six-digit postcode-level hazard publicity vulnerability mannequin based mostly on UK flood threat estimates (masking river, floor water, and coastal flooding) with an insurance coverage pricing mannequin and borrower-level knowledge on mortgages and incomes. Then, we estimate anticipated flood losses and residential insurance coverage premia. We plug this into our present situation evaluation toolkits to translate greater premia into home value and credit score threat impacts.
As with all local weather and insurance coverage fashions, the outcomes rely upon many judgement calls. We use a stylised set of hazard fashions and a extreme long-term local weather situation which is topic to deep uncertainty. Whereas the mannequin is well-calibrated to the UK monetary system, the insurance coverage premium, home value, and stress-testing fashions we use are illustrative, not definitive. So, the estimates right here needs to be handled as indicative.
We use the mannequin to reply three key questions.
1) How massive may insurance coverage safety gaps develop into?
In our modelled 2025 situation, 95% of mortgagors have constructing and contents insurance coverage and we assign every family an insurance coverage premium, averaging round £430 per 12 months (aqua bar in Chart 1). By 2050, we assume Flood Re ends and flood threat rises. We conservatively assume that insurers not cowl beforehand subsidised properties, and that mortgagors cease paying for insurance coverage if the premium will increase above a threshold share of their revenue.
This leads the safety hole to as a lot as double, from 5% immediately to six.8-10.2% in 2050 – not removed from insurers’ 2021 estimates. This might depart as many as 910,000 mortgagors with out flood insurance coverage (orange bar).
That 6.8%–10.2% hole assumes insurers have excellent details about will increase in flood threat. However the uncertainty and complexity in modelling dangers on the property degree imply data is often imperfect, and subsequently excessive occasions usually result in up to date perceptions of hazard threat and better premia. To seize this, we simulate an illustrative 1-in-100 flood 12 months beneath RCP8.5 and assume that premia improve quickly for these homes flooded. In that situation, the safety hole will increase considerably to round 1.39 million mortgagors (15.7%) in 2050 (purple bar).
Chart 1: Estimates of the mortgagor insurance coverage safety hole
Notice: Beneath situation RCP8.5. Pattern of 6.85 million mortgages has been upscaled to eight.8 million to replicate the entire UK mortgage market. Mortgage inventory as of end-2024. Flood Re assumed to finish in 2039. Estimates are topic to substantial uncertainty. ‘Uninsured’ outlined as any properties for which insurance coverage is estimated to be unaffordable (ie above a sure share of gross revenue, calibrated for every revenue decile utilizing ONS Dwelling Prices and Meals Survey knowledge) or unavailable. Aqua bar reveals the approximate present protection hole. Orange bar reveals vary of hole estimates beneath greater local weather threat (RCP8.5 2050), no Flood Re and numerous threat reflective pricing fashions. Purple bar displays homes uninsured after a 1-in-100 flood 12 months results in excessive markups in insurance coverage premia for these homes flooded.
Sources: FCA Product Gross sales Information, Mitiga, RiskLayer, ONS Dwelling Prices and Meals Survey and Financial institution workers calculations. Full sources can be found upon request.
Some assumptions we make are conservative – for instance, that households’ willingness to pay for insurance coverage is mounted over time, whilst flood threat will increase. However in different methods, we could possibly be understating the dangers. The hazard mannequin we use is very unsure, and doesn’t seize non-linearities or tipping factors within the earth system, and we solely seize the influence of flooding, not different hazards like windstorms or subsidence.
Both approach, will increase in flood threat beneath local weather change may depart an growing variety of mortgagors uninsured towards the detrimental impacts of maximum climate occasions. Notably, mortgagors with out enough insurance coverage could discover it tougher to remortgage, notably if lenders view uninsured properties as greater threat – additional amplifying monetary vulnerability in affected areas.
2) What may that imply for home costs?
Safety gaps may have a spread of considerable social and financial impacts – notably for households left uninsured. We concentrate on their monetary impacts, asking if associated home value falls could possibly be giant sufficient to disrupt the provision of important providers to UK households and companies.
Constructing on earlier Financial institution work, we mannequin three channels by way of which home costs are discounted: greater anticipated insurance coverage premia (in web current worth phrases); estimated unaffordability/unavailability of insurance coverage, and anticipated flood damages for uninsured properties.
In combination, the home value falls in our mannequin are small in comparison with these seen in earlier monetary crises, at round 1%–3% in our central case, or 3%–5% following an excessive climate occasion. That is a lot decrease than the year-on-year fall of 15.6% seen after the worldwide monetary disaster, or the 28% assumed within the 2025 Financial institution Capital Stress Take a look at situation.
However nationwide averages masks giant impacts in some areas: Chart 2 reveals that as many as 18% of mortgaged properties may see a fall larger than 10% following a extreme flood occasion, and virtually 3% may expertise falls over 30% beneath conservative assumptions. These estimates match with estimates the Financial institution revealed beforehand, however this mannequin assessments additional sensitivities and situations.
Chart 2: Distribution of falls in home costs beneath totally different situations
Notice: Beneath situation RCP8.5. Home value falls replicate the web current worth of anticipated will increase in insurance coverage premia, reductions for estimated insurance coverage unaffordability or unavailability, and the worth of flood damages for uninsured properties. Orange bars are in step with the 6.8%–10.2% safety hole in Chart 1, purple bars with the 15.7% hole. Ranges replicate totally different discounting and insurance coverage pricing assumptions.
Sources: FCA Product Gross sales Information, Mitiga, RiskLayer, ONS Dwelling Prices and Meals Survey and Financial institution workers calculations. Full sources can be found upon request.
3) May these results result in losses for banks?
To discover spillovers from home value falls to banks, we use a easy stress testing mannequin. We calculate present and careworn mortgage to worth and debt-servicing ratios to seize the influence of decrease home costs and better family expenditures on the likelihood of default and loss given default of UK mortgages.
This mannequin captures the direct impacts of insurance coverage premia and decrease home costs on affordability, however doesn’t seize the oblique impacts of flooding on consumption, leverage, output or inflation. So, our evaluation is partial.
Intuitively, will increase in mortgage impairment charges are small relative to giant macro stresses to which UK banks are stress examined, even beneath extreme assumptions (Chart 3). This impact shouldn’t be even throughout the nation although – Chart 3 reveals the impacts could possibly be practically 4 instances the common in greater flood-risk areas.
Chart 3: Impression of various situations on two key measures of financial institution credit score threat
Notice: Beneath situation RCP8.5. Anticipated impairment charges replicate adjustments in loss given default and likelihood of default because of adjustments in mortgage to worth and debt-service capacity ratios because of greater flooding and decrease insurance coverage protection. Aqua diamonds replicate baseline anticipated impairment charges with no flood impacts. Orange bars correspond to the vary of home value falls within the orange bars in Chart 2. Purple diamonds in step with the high quality of the purple bars in Chart 2. Inexperienced line is a weighted common of the purple diamonds. Gold line relies on the revealed outcomes of the 2025 Financial institution Capital Stress Take a look at. The hazard mannequin we use suggests excessive flood threat within the North East and North West of England, although the relative distribution of dangers differs between hazard mannequin suppliers.
Sources: FCA Product Gross sales Information, Mitiga, RiskLayer, ONS Dwelling Prices and Meals Survey and Financial institution workers calculations. Full sources can be found upon request.
Our benign combination end result displays three well-established options of the UK mortgage market:
- The massive majority of UK mortgages on banks’ books have a mortgage to worth ratio of under 70%, insulating mortgages from falls in home costs.
- UK flood insurance coverage protection is excessive, and pricing is inexpensive relative to many different international locations.
- Flooding is a geographically sure threat driver, that means giant impacts even throughout giant areas common out to smaller impacts on the nationwide degree.
That stated if a extreme flood occasion had been to coincide with different stresses, it may amplify monetary stability dangers. Safety gaps may additionally pose dangers to smaller lenders with portfolios concentrated in high-flood threat areas.
Conclusion and coverage implications
Our mannequin outcomes recommend that UK mortgagor safety gaps are unlikely to threaten banking system solvency, however that is topic to many caveats. We solely cowl the prevailing inventory of buildings, as we can’t seize the publicity or resilience of deliberate new builds. We don’t but seize will increase in threat after 2050, or different key perils, belongings (eg industrial actual property and non-mortgaged homes), or contagion channels (corresponding to macro impacts).
Our outcomes are related to monetary regulators:
The outcomes may additionally inform judgements by governments concerning the impacts of local weather change, together with prices to households from elevated flood threat, the tip of Flood Re, and the potential advantages of planning and adaptation measures to enhance monetary and bodily resilience.
Flood safety gaps may considerably influence financial welfare. Whereas our outcomes recommend they could not threaten banking system resilience, they might have a spread of detrimental penalties for affected households, in addition to lenders uncovered to high-risk areas, and wider financial development. Given the relevance of safety gaps to many stakeholders, cross-industry collaboration might be wanted to assist stop climate-related dangers from spilling over to the broader monetary system.
Will Banks and Kemal Erçevik work within the Financial institution’s Cross-cutting Technique and Rising Dangers Division.
The authors are grateful to Howden Re (Rowan Douglas, Man Wai Cheung, Wes Hibbert, Tim Edwards, Dr Nidia Martinez and Naomi Worth), RiskLayer (Professor James Daniell, Dr Bijan Khazai and Dr Andreas Schaefer) and Mitiga (Dr Alex Marti and Dr Foteini Baladima) who offered intensive insurance coverage sector insights, flood hazard and different local weather modelling for this work.
If you wish to get in contact, please electronic mail us at bankunderground@bankofengland.co.uk or depart a remark under.
Feedback will solely seem as soon as authorised by a moderator, and are solely revealed the place a full identify is provided. Financial institution Underground is a weblog for Financial institution of England workers to share views that problem – or assist – prevailing coverage orthodoxies. The views expressed listed here are these of the authors, and will not be essentially these of the Financial institution of England, or its coverage committees.
Share the put up “Opening the floodgates? Modelling spillovers from flood insurance coverage safety gaps to UK mortgages”
