Risk Measures for the Climate Transition Age: Why Symmetric Risk Budgets are unlikely to mitigate two-dimensionally asymmetric Climate Change risks

By Lars Dijkstra, Andreas G. F. Hoepner, Fabiola I. Schneider, Agnieszka Słomka-Gołębiowska

Rating

1149
Battle Count: 50

Relevance

8/10
Highly relevant for quantitative portfolio managers and risk analysts focusing on ESG and climate transition strategies. It challenges standard risk constraints (tracking error) used in active management, offering a more nuanced risk definition (downside risk) that could significantly alter portfolio construction and constraint optimization in climate-aware funds.

Implementation Complexity

4/10
The mathematical formulas for Lower Partial Moments (LPMs), semi-variance, and trailing error are standard and computationally simple to implement. The complexity lies in the operational and regulatory change management required to shift from symmetric to asymmetric risk budgets in institutional mandates.

Reproducibility

3/5
The paper provides a theoretical argument and specific formulas for downside risk measures in the Technical Appendix. It references public data (Russell 1000) for an illustrative figure but does not provide code or a full dataset for replication of the entire argument. The methodology is conceptual rather than empirical simulation-based.

Abstract

The most widely used investment risk measures - variance, standard deviation, and tracking error - treat upside deviations as equally undesirable as downside losses. In stable markets with assumed symmetric return distributions, this simplification is potentially harmless. In the climate transition age, it is not. Climate risk is two-dimensionally asymmetric, across assets and over time. Both dimensions are negatively skewed against investors. Hence, climate transition investment strategies deliberately deviate from benchmarks that reflect an insufficiently decarbonising global economy. When fiduciaries enforce tracking error budgets that penalise outperformance just as heavily as underperformance, they inadvertently constrain exactly the portfolio return opportunities that climate-aware investing seeks. We argue that replacing symmetric deviation-based risk measures with their downside-only counterparts - semi-variance, standard risk and trailing error - resolves this conflict without sacrificing any fiduciary discipline. The distinction is not merely semantic: as the gap between climate transition trajectories and market benchmarks widens over the coming decades, symmetric risk budgets will become binding constraints on transition strategies well before actual investment risk warrants it. We propose specific changes to mandate design that would allow institutional investors to pursue climate transition opportunities within genuinely risk-aware (rather than deviation-averse) frameworks.

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