From Hazard to Default: Measuring Sector Vulnerability in Corporate Credit Risk
Introduction
Floods, heatwaves and droughts are already hurting corporate balance sheets, but the credit models that decide who gets financed, at what price and with how much capital barely register them. Traditional credit scoring is built on historical financial data. Climate impacts show up in default statistics only after the damage is done, never as a distinct, forward-looking risk factor. European supervisory authorities increasingly expect banks to integrate physical climate risk into credit risk assessment, yet the regulatory framework provides limited guidance on how this should be achieved in practice. They say even less about how to recognise the risk-reducing value of adaptation.
The CLIMATEFIT report Pricing Resilience: Adaptation Adjustment and Sector Vulnerability in Corporate Credit Risk closes this gap with two practical solutions. The first is a sector vulnerability framework that scores how exposed each economic activity is to climate hazards. The second is a methodology that uses this score to adjust probabilities of default (PD). Together they are tested against one of Italy’s most destructive recent climate events, the 2023 floods in Emilia-Romagna and Tuscany. The tested methodology shows that physical climate risk can be measured, priced and governed with information that lenders already hold.
Key Findings and Insights
Climate vulnerability is structural, not uniform. The same flood can be a manageable disruption for one business and an existential threat for its neighbour. The framework traces risk through three transmission channels: how much value sits in fixed physical assets, how much output depends on exposed or outdoor labour, and how directly the business relies on climate-conditioned inputs such as water, crops or temperature-controlled processes. Built on the financial statements of companies based in the four Italian provinces hit by the 2023 floods (Ravenna and Forlì-Cesena in Emilia-Romagna, Prato and Pistoia in Tuscany), the framework scores all 87 NACE sectors against 13 hazards from the EU Taxonomy. The result is a single 1–100 Vulnerability Intensity Sector score (VIS), grouped into seven classes.
The vulnerability map overturns some easy assumptions. Agriculture, building construction, and accommodation and food services rank at the extreme end. Food and textile manufacturing, energy utilities and real estate follow closely behind, with very high vulnerability. Software, consultancy and financial services sit at the bottom. The scoring is deliberately conservative: a hazard that hits a business hard through one channel counts for more than one that touches it lightly through several.
The 2023 floods offer real-world proof. Across 18,887 rated firms in the affected provinces, average PD rose steadily from 3.66% in 2022 to 4.26% in 2025. The share of firms in the riskiest rating classes grew from 17.7% to 19.3%, and downgrades outnumbered upgrades every year. Most importantly, default rates tracked sector vulnerability. Firms in high-vulnerability sectors defaulted at 0.51% over 2024–2025, more than twice the 0.23% rate of the least vulnerable. Statistical tests confirmed the positive relationship in every specification. Voluntary liquidations showed no such pattern, which points to a climate-driven signal rather than general business churn.
The real impact is probably larger than it looks. Flood-related loan moratoria legislation let borrowers defer repayments without triggering default, and the 2023 credit scores partly reflected the post-pandemic rebound in 2021–2022 financial statements. The evidence portrays climate vulnerability as an incremental stress factor: rarely the sole cause of default, but a consistent force pushing credit quality down.
A simple, transparent adjustment captures this signal. The proposed Adaptation-Adjusted Credit Rating (AACR) methodology scales each borrower’s PD by a factor that multiplies location-specific flood probability by sector vulnerability. In line with the IPCC view of risk, the two components interact rather than add up. A vulnerable firm in a safe location, or a resilient firm in a flood zone, receives only a small uplift. One calibrated parameter governs the model, which caps any increase at 25% and never lowers a PD.
The effect is targeted, not blunt. Applied to the study portfolio, the adjustment raises average PD by about 0.2 percentage points, roughly 5%. For half of all borrowers the uplift is negligible. It is concentrated in the top decile, where PDs rise by more than 16.5%, and in financially weaker firms in high-hazard areas: one high-risk borrower’s PD moves from 28.2% to 34.2%. Rating structures stay largely intact, with around 300 firms a year moving one notch in the mid-risk segment. On EUR 10.9 billion of outstanding debt, the adjustment adds EUR 7.1 million in expected losses. That is a quantified, defensible figure for climate risk that is currently priced at zero.
It works with the models banks already have. The method needs only three inputs: a PD, a sector code and a location. It can therefore sit on top of standardised, foundation-IRB and advanced-IRB approaches, as well as external ratings, without rebuilding existing models. A ready-to-use Excel VIS Calculation Tool lets institutions screen portfolios and prioritise due diligence.
Why It Matters
For banks and lenders, the methodology turns a supervisory expectation into an auditable risk metric. It can be used for portfolio steering, climate stress testing, pricing and disclosure, and it does not disrupt regulatory capital models. For risk managers, it pinpoints where losses will concentrate: at the overlap of vulnerable sectors, high-hazard locations and weaker credit profiles, not across the whole book.
For policymakers and supervisors, it shows that physical risk integration is achievable now with data that already exists. It also offers a blueprint for moving prudential frameworks beyond principles. For businesses, especially in agriculture, construction, tourism, manufacturing and real estate, the message is direct: climate exposure is becoming a credit variable. Firms that understand and reduce their vulnerability will be better placed when it is priced in.
This also changes the economics of adaptation. Once vulnerability is measured in the same terms as credit risk, resilience investments acquire a visible financial value. Firm-level adaptation, asset geolocation and multi-hazard coverage are the next steps the report identifies to strengthen this link.
Key Takeaways
- Physical climate risk is a blind spot in credit scoring. It appears in default data only after the damage is done.
- Vulnerability depends on how a business makes money: its assets, its workforce and its reliance on climate. The same hazard does not hit every sector the same way.
- The evidence is empirical. After the 2023 Italian floods, firms in highly vulnerable sectors defaulted at more than twice the rate of the least vulnerable.
- Risk lies where hazard and vulnerability meet. A multiplicative adjustment targets the firms truly at risk instead of penalising whole sectors or regions.
- Modest on average, material where it counts. Average PD rises by about 5%, while the most exposed borrowers see increases of up to 25%.
- No new models are needed. A PD, a sector code and a location are enough to apply the adjustment across standard and internal rating approaches.
- Measuring vulnerability is the first step to rewarding adaptation. It gives resilience a value that can be seen in lending and capital decisions.
The full report provides the complete sector-by-sector vulnerability assessments and the statistical evidence from the 2023 floods. It also includes a worked portfolio case study and the open VIS Calculation Tool. Banks, supervisors, investors and businesses who want to move climate risk from disclosure into decision-making will find the evidence and the tools to start. Download Pricing Resilience: Adaptation Adjustment and Sector Vulnerability in Corporate Credit Risk to explore the methodology in depth.
This report is a component of the Project Result 4 of the CLIMATEFIT project. Project Result 4 develops CLIMATEFIT’s dedicated pathway for Financial & Investment Entities (FIEs) to accelerate climate adaptation finance.
