Climate-Related Financial Risks
Taxonomy, Transmission, and Materiality
Overview
Where This Lesson Fits
This is the first of six lessons in Module 4: Green Finance Products and Services. It establishes the conceptual foundation for understanding how climate change creates financial risk, providing the taxonomy and transmission frameworks that every subsequent lesson builds upon.
The lesson progresses from basic risk classification (physical, transition, liability) through the channels by which climate events propagate into financial losses, to the concept of materiality that determines which risks demand immediate action.
Learning Outcomes
- Classify climate risks into physical, transition, and liability categories with precise sub-classifications
- Map transmission channels linking climate events to financial losses through credit, market, operational, and liquidity pathways
- Distinguish short-, medium-, and long-term risk horizons and their implications for portfolio management
- Apply double materiality (financial vs impact) to sectoral analysis across ASEAN economies
- Assess Vietnam Mekong Delta climate vulnerability for bank portfolios using structured frameworks
Prerequisites
None. This is the Foundation level entry point for Module 4. No prior knowledge of climate science or risk management is assumed.
Slide Deck
Lecture Slides (33 Slides)
Download Slide Deck (PDF)Foundation Level
Physical Risks
Acute Physical Risks
Event-driven hazards that cause immediate damage to assets, infrastructure, and supply chains. These include typhoons and cyclones, riverine and coastal flooding, wildfires, heatwaves, and severe storms. Their financial impact is concentrated but can be catastrophic for exposed portfolios.
- Typhoons and cyclones — wind damage, storm surge, rainfall-induced flooding
- Flooding — riverine overflow, flash floods, coastal inundation from storm surge
- Wildfires — direct asset destruction, air quality impacts on productivity
- Heatwaves — labor productivity losses, increased energy demand, crop failure
Chronic Physical Risks
Long-term shifts in climate patterns that gradually erode asset values and economic productivity. These risks are slower-moving but often more pervasive and harder to reverse.
- Sea-level rise — coastal real estate devaluation, infrastructure retreat costs
- Temperature shift — agricultural yield changes, cooling cost increases, species migration
- Precipitation changes — drought frequency, water scarcity, altered hydropower output
Transition Risks
Risks arising from the adjustment toward a lower-carbon economy. The speed, scale, and coordination of the transition determine the magnitude of financial losses.
Five Transition Risk Channels
- Policy and Legal — Carbon pricing mechanisms (taxes, ETS), regulations mandating emissions reductions, energy efficiency standards, land-use restrictions
- Technology — Disruptive clean technologies rendering existing assets obsolete: renewable energy cost declines, battery storage breakthroughs, green hydrogen scaling
- Market — Shifts in supply and demand: changing consumer preferences, commodity price volatility, reduced demand for fossil fuel products
- Reputation — Stakeholder perception shifts: investor divestment campaigns, consumer boycotts, employee recruitment challenges for high-carbon firms
- Behavioral — Changes in individual and institutional behavior: ESG-driven capital allocation, green procurement policies, lifestyle shifts reducing carbon-intensive consumption
Liability Risks
The emerging third category of climate risk, increasingly recognized as distinct from transition risks. Liability risks arise when parties seek compensation for climate-related losses through legal or regulatory action.
Three Sub-categories
- Litigation — Lawsuits against emitters for climate damages, failure to disclose climate risks, or breach of fiduciary duty in climate-related investment decisions
- Adaptation failure — Legal liability for failing to adapt infrastructure, products, or services to known climate risks (e.g., building codes in flood zones)
- Greenwashing — Regulatory enforcement and civil litigation against misleading environmental claims in financial products, corporate reporting, or marketing
Transmission Channels
Transmission channels describe how climate events propagate into financial losses. Understanding these channels is essential for quantifying and managing climate-related portfolio exposure.
Four Financial Risk Channels
- Credit risk — Climate events reduce borrower income or collateral values, increasing probability of default (PD) and loss given default (LGD). Example: drought destroys crops, farmer cannot repay agricultural loan, land value declines as collateral.
- Market risk — Abrupt repricing of securities when climate risks are suddenly recognized. Example: stranded asset revaluation in fossil fuel equities, sovereign bond repricing for climate-vulnerable nations.
- Operational risk — Climate disrupts business operations directly. Example: flooding damages bank branch networks, data centers lose cooling capacity during heatwaves, supply chains break during extreme weather.
- Liquidity risk — Climate events trigger simultaneous demand for liquidity across the system. Example: mass insurance claims after a typhoon, deposit withdrawals in affected regions, fire-sale of climate-exposed assets.
Time Horizons
Climate risks operate across fundamentally different timescales, creating a mismatch with traditional financial planning horizons. Mark Carney's "tragedy of the horizon" describes how the catastrophic impacts of climate change will be felt beyond the traditional horizons of most actors.
Acute physical events and sudden policy shocks. Relevant to: trading books, insurance underwriting, annual budgets. Examples: typhoon season losses, new carbon tax implementation, regulatory enforcement actions.
Transition risk acceleration and chronic physical onset. Relevant to: corporate loan books, infrastructure investment, strategic planning. Examples: technology disruption cycles, CBAM full implementation, accumulating sea-level rise impacts.
Systemic transformation and potential tipping points. Relevant to: sovereign bonds, pension funds, real estate, insurance solvency. Examples: AMOC slowdown, West Antarctic ice sheet collapse, mass climate migration, stranded nation risk.
Materiality
Materiality determines which climate risks matter enough to require action. Three competing frameworks define materiality differently, with major implications for risk management scope.
Financial Materiality (Outside-In)
How climate affects the firm's enterprise value. This is the ISSB/IFRS approach: a climate risk is material if it could reasonably be expected to influence investor decisions. Focus: financial performance, cash flows, asset values.
Impact Materiality (Inside-Out)
How the firm's activities affect the climate and broader society. This is the GRI approach: a firm's contribution to climate change is material regardless of financial impact. Focus: emissions, resource use, ecological damage.
Double Materiality (Both Directions)
The EU CSRD approach combines both lenses. A climate risk is material if it affects the firm's value (financial materiality) or if the firm's activities affect climate outcomes (impact materiality). This is the most comprehensive framework and the direction of ASEAN regulatory convergence.
Intermediate Level
Sectoral Exposure Mapping
Systematic assessment of how physical and transition risks affect different economic sectors. Sectors are ranked by exposure to construct a 10-sector risk profile.
High-Exposure Sectors
| Sector | Physical Risk | Transition Risk | Overall |
|---|---|---|---|
| Energy (fossil fuels) | High | Very High | Very High |
| Agriculture | Very High | Medium | Very High |
| Real Estate | High | High | High |
| Transport | Medium | High | High |
| Manufacturing | Medium | High | High |
| Tourism | High | Medium | High |
| Fisheries & Aquaculture | Very High | Low | High |
| Mining | Medium | High | Medium-High |
| Financial Services | Low | Medium | Medium |
| Technology | Low | Low | Low |
Compound Risk Analysis
Climate risks rarely occur in isolation. Compound risk analysis examines how multiple climate drivers interact to produce non-linear financial losses that exceed the sum of individual risk assessments.
Interaction Types
- Physical + Physical — Drought followed by flooding on hardened soil; heatwave + wildfire cascades
- Physical + Transition — Drought reduces agricultural output while a new carbon tax raises input costs, creating a margin squeeze
- Transition + Transition — Simultaneous technology disruption (EVs) + policy tightening (emissions standards) accelerating stranded asset creation
- Feedback loops — Climate damage reduces fiscal capacity to invest in adaptation, increasing future damage severity
Risk Heatmap Construction
A 10-sector by 6-risk-type matrix provides a visual summary of portfolio-level climate exposure. Each cell is scored 1–5 based on scenario data and expert judgment.
Methodology
- Define sectors (rows): Energy, Agriculture, Real Estate, Transport, Manufacturing, Tourism, Fisheries, Forestry, Mining, Financial Services
- Define risk types (columns): Acute Physical, Chronic Physical, Policy Transition, Technology Transition, Market Transition, Litigation
- Score each cell 1–5 using NGFS scenario data, country-specific climate projections, and regulatory trajectory analysis
- Weight cells by portfolio exposure (loan book concentration) to derive portfolio-level risk scores
- Identify red zones (score 4–5) requiring immediate risk management attention
where $w_s$ is the portfolio weight of sector $s$ and $\text{Score}_{s,r}$ is the 1–5 risk score for sector $s$, risk type $r$.
Worked Example: ASEAN Bank Portfolio
Apply the Climate Value-at-Risk framework to a hypothetical ASEAN commercial bank's loan portfolio. The model adjusts baseline probability of default using a climate sensitivity parameter.
Parameter Definitions
- $\text{PD}_{\text{base}}$ — Baseline probability of default (historical, non-climate-adjusted)
- $\Delta T$ — Temperature change scenario (e.g., +1.5°C, +2.0°C, +3.0°C)
- $\beta_{\text{climate}}$ — Climate sensitivity coefficient (sector-specific, estimated from NGFS damage functions)
- $\text{LGD}$ — Loss given default (recovery rate adjustment for climate-damaged collateral)
- $\text{EAD}$ — Exposure at default (outstanding loan balance at the sector level)
Example Calculation
For the Agriculture sector under a +2.0°C scenario:
Compare to non-climate baseline: $0.05 \times 0.60 \times \$300\text{M} = \$9.0\text{M}$. The climate adjustment adds $6.3M (70% increase) in expected losses.
PhD Extension
Risk Taxonomy Evolution
The taxonomy of climate-related financial risks has evolved through successive institutional frameworks, each expanding scope and granularity.
Institutional Timeline
| Year | Framework | Contribution |
|---|---|---|
| 2015 | Carney / FSB | "Tragedy of the Horizon" speech; established physical, transition, liability trichotomy; created TCFD |
| 2017 | TCFD | Standardized four-pillar disclosure framework; mainstream legitimation of climate risk |
| 2019 | NGFS | Central bank scenario framework; quantitative pathways linking climate to macro-financial variables |
| 2023 | TNFD | Extended taxonomy to nature-related risks; LEAP approach; biodiversity-finance nexus |
| 2024 | ISSB | IFRS S2 global baseline standard; integration with financial accounting; mandatory in 20+ jurisdictions |
Endogenous vs Exogenous Risk
Battiston et al. (2017) demonstrated that climate risk is not purely exogenous. Financial network structure creates endogenous amplification: initial climate shocks propagate through interbank exposures, portfolio overlaps, and fire-sale dynamics, creating losses far exceeding the direct physical or transition impact.
where $R_i(t)$ is the risk exposure of institution $i$ at time $t$, $w_{ij}$ is the network weight (exposure of $i$ to $j$), and $\Delta V_j(t)$ is the change in value of institution $j$'s portfolio due to climate impacts.
Key Insights
- Direct climate losses may be manageable, but network amplification can create systemic crises
- Portfolio concentration in climate-exposed sectors creates correlated defaults
- Fire-sale externalities emerge when multiple institutions simultaneously deleverage from the same assets
- The financial system's network structure is itself a source of climate risk
Network Propagation Models
Three mechanisms through which climate risk propagates in financial networks:
1. Contagion
Direct counterparty exposure: when institution $j$ defaults due to climate losses, institution $i$ loses its claims on $j$. The cascade continues through chains of interbank lending, derivatives counterparty risk, and trade credit networks.
2. Fire Sales
Indirect propagation through asset markets: institutions forced to sell climate-exposed assets depress prices, imposing mark-to-market losses on all holders of similar assets. This creates a common exposure channel even without direct bilateral links.
3. Amplification
Positive feedback loops between contagion and fire sales. Counterparty losses trigger margin calls, forcing further asset sales, which depress prices, causing more counterparty losses. The result is non-linear loss escalation that can transform a sector-specific climate shock into a system-wide financial crisis.
Climate Litigation as Systematic Risk
Setzer and Higham (2023) document 2,341 climate litigation cases across 50+ jurisdictions, establishing litigation as a systematic rather than idiosyncratic risk. The Grantham Research Institute database shows exponential growth since 2015.
Litigation Categories
- Climate-aligned — Cases seeking stronger climate action: emission reduction orders, policy challenges, corporate accountability
- Climate-obstructive — Cases challenging climate regulations: ETS validity, renewable energy mandates, stranded asset compensation
- Disclosure-based — Shareholder suits for inadequate climate risk disclosure: securities fraud, breach of fiduciary duty
- Greenwashing — Consumer and regulatory actions against misleading environmental claims in financial products
Financial System Implications
Litigation risk creates a contingent liability that is difficult to quantify but potentially enormous. The Shell ruling (2021) demonstrated that courts can mandate emissions reductions with binding financial consequences. For financial institutions, litigation risk manifests through: (1) direct liability for portfolio companies, (2) failure to disclose climate risks to investors, (3) greenwashing in sustainable finance products.
Quantitative Lab
Climate Risk Heatmap Construction
Python Pseudocode
Lab Steps
- Download NGFS Phase IV scenario data for three ASEAN countries (Vietnam, Thailand, Philippines) from the IIASA Scenario Explorer
- Extract World Bank climate indicators (temperature projections, precipitation changes, sea-level rise) from the Climate Change Knowledge Portal
- Construct a 10x6 scoring matrix by combining scenario projections with sectoral vulnerability assessments. Score each cell 1–5.
- Apply portfolio weights based on a hypothetical ASEAN bank loan book to compute the portfolio-weighted risk score: $R_{\text{portfolio}} = \sum_s \sum_r w_s \cdot \text{Score}_{s,r}$
- Visualize as annotated heatmap using seaborn. Identify the top 3 sector-risk combinations requiring priority risk management. Export as PDF.
Data Sources
Case Study: Vietnam — Mekong Delta
Mekong Delta Climate Vulnerability & Bank Portfolio Assessment
Geographic Context
The Mekong Delta encompasses 12 provinces in southern Vietnam, home to approximately 17 million people. It produces 50% of national rice output and 90% of aquaculture exports, making it Vietnam's agricultural heartland and one of the most climate-exposed economic zones in Southeast Asia.
Climate Threats
- Saltwater intrusion — Currently reaching 60–90km inland during dry seasons; projected to extend 40–50km further by 2050
- Sea-level rise — Under a 1-meter rise scenario (plausible by 2100), approximately 40% of the Delta is at risk of inundation
- Increased flooding — Upstream hydropower development combined with more intense monsoon rainfall increases peak flood frequency
- Temperature increase — Projected +1.5–2.5°C by 2050, reducing rice yields by 10–20% in affected areas
Bank Portfolio Exercise
Assess the climate risk exposure of a hypothetical Vietnamese commercial bank with the following loan portfolio concentration in the Mekong Delta region:
Three-Horizon Assessment Framework
For each sector above, students assess climate risk across three time horizons:
| Horizon | Timeframe | Key Risks | Assessment Focus |
|---|---|---|---|
| Short | 0–3 years | Typhoon damage, seasonal flooding, acute saltwater intrusion events | PD increase for agricultural loans, collateral damage, insurance gaps |
| Medium | 3–10 years | Progressive saltwater intrusion, transition to saline-tolerant crops, infrastructure adaptation needs | Sectoral reallocation, real estate repricing, technology investment requirements |
| Long | 10–30 years | Permanent inundation risk, mass relocation, fundamental economic transformation | Stranded real estate, sovereign risk implications, portfolio exit strategy |
Assessment Rubric
| Criterion | Weight | Excellent (5) | Adequate (3) | Insufficient (1) |
|---|---|---|---|---|
| Risk identification | 25% | All three risk types identified per sector with specific examples | Two risk types per sector, general examples | Single risk type, no sector differentiation |
| Transmission mapping | 25% | Clear causal chains from climate event to financial loss for each channel | Partial transmission chains, some channels missing | No transmission analysis |
| Time horizon analysis | 20% | Distinct risk profiles across all three horizons with quantitative estimates | Two horizons addressed, qualitative analysis | Single time horizon |
| Materiality assessment | 15% | Double materiality applied with sector-specific financial and impact analysis | Single materiality lens | No materiality discussion |
| Portfolio recommendations | 15% | Specific, actionable recommendations with risk mitigation strategies per sector | General recommendations | No recommendations |
Key Concepts
Glossary (15 Terms)
- Acute physical risk
- Event-driven climate hazards causing immediate damage: typhoons, floods, wildfires, heatwaves. Characterized by sudden onset and concentrated impact.
- Chronic physical risk
- Long-term shifts in climate patterns that gradually erode economic value: sea-level rise, sustained temperature increases, changing precipitation patterns.
- Compound risk
- The interaction of multiple climate risk drivers producing non-linear financial losses exceeding the sum of individual risks assessed independently.
- Credit risk
- The risk of financial loss from a borrower's failure to repay. Climate-adjusted credit risk incorporates increased PD and LGD from climate-related income or collateral impairment.
- Double materiality
- The EU CSRD framework requiring assessment of both how climate affects firm value (financial materiality) and how the firm affects climate outcomes (impact materiality).
- Financial materiality
- The ISSB/IFRS approach: a climate risk is material if it could reasonably influence investor decisions about enterprise value. Outside-in perspective.
- Impact materiality
- The GRI approach: a firm's climate impacts are material regardless of whether they affect the firm's own financial performance. Inside-out perspective.
- Liability risk
- Legal and regulatory risk from climate-related litigation, adaptation failure claims, or greenwashing enforcement actions against firms or their financiers.
- Liquidity risk
- Risk that climate events trigger simultaneous liquidity demands: mass insurance claims, deposit withdrawals, fire-sale of climate-exposed assets across the system.
- Market risk
- Risk of financial loss from sudden repricing of securities when climate risks are recognized: stranded asset devaluation, sovereign bond repricing, commodity price shocks.
- Operational risk
- Risk of loss from climate-related disruption to business operations: physical damage to infrastructure, supply chain failures, workforce displacement.
- Physical risk
- The umbrella category for all climate-related risks arising from the physical impacts of climate change, encompassing both acute events and chronic shifts.
- Stranded assets
- Assets that have suffered unanticipated or premature write-downs, devaluations, or conversion to liabilities due to climate-related policy, technology, or market changes.
- Transition risk
- Financial risks arising from the process of adjusting toward a low-carbon economy, including policy, technology, market, reputation, and behavioral channels.
- Transmission channel
- The mechanism by which a climate event propagates into financial loss: credit risk, market risk, operational risk, or liquidity risk pathways.
References
Key References
- 2015 Carney, M. "Breaking the Tragedy of the Horizon: Climate Change and Financial Stability." Speech at Lloyd's of London, Bank of England.
- 2017 Battiston, S., Mandel, A., Monasterolo, I., Schuetze, F., & Visentin, G. "A Climate Stress-Test of the Financial System." Nature Climate Change, 7(4), 283–288.
- 2024 NGFS. "Climate Scenarios for Central Banks and Supervisors: Phase IV." Network for Greening the Financial System.
- 2021 ADB. "Asian Development Outlook: Financing a Green and Inclusive Recovery." Asian Development Bank.
- 2023 Setzer, J. & Higham, C. "Global Trends in Climate Change Litigation: 2023 Snapshot." Grantham Research Institute, London School of Economics.
- 2017 TCFD. "Final Report: Recommendations of the Task Force on Climate-Related Financial Disclosures." Financial Stability Board.
- 2024 ISSB. "IFRS S2: Climate-related Disclosures." International Sustainability Standards Board.
- 2016 Dietz, S., Bowen, A., Dixon, C., & Gradwell, P. "'Climate Value at Risk' of Global Financial Assets." Nature Climate Change, 6, 676–679.