Rising Temperatures, Falling Ratings: The Effect of Climate Change on Sovereign Creditworthiness

Patrycja Klusak - Prof. on University of East Anglia. The seminar is reserved to the Department of Management

  • Date: 28 March 2023 from 12:00 to 13:00

  • Event location: On line (Teams) and live in Aula Seminari 1, via Capo di Lucca 34, Bologna

Enthusiasm for 'greening the financial system' is welcome, but a fundamental challenge remains: financial decision makers lack the necessary information. It is not enough to know that climate change is bad. Markets need credible, digestible information on how climate change translates into material risks. To bridge the gap between climate science and real-world financial indicators, we simulate the effect of climate change on sovereign credit ratings for 108 countries, creating the world's first climate-adjusted sovereign credit rating. Under various warming scenarios, we find evidence of climate-induced sovereign downgrades as early as 2030, increasing in intensity and across more countries over the century.

We find strong evidence that stringent climate policy consistent with limiting warming to below 2°C, honouring the Paris Climate Agreement, and following RCP 2.6 could nearly eliminate the effect of climate change on ratings. In contrast, under higher emissions scenarios (i.e., RCP 8.5), 63 sovereigns experience climate-induced downgrades by 2030, with an average reduction of 1.02 notches, rising to 80 sovereigns facing an average downgrade of 2.48 notches by 2100.

We calculate the effect of climate-induced sovereign downgrades on the cost of corporate and sovereign debt. Across the sample, climate change could increase the annual interest payments on sovereign debt by US$ 22–33 billion under RCP 2.6, rising to US$ 137–205 billion under RCP 8.5. The additional cost to corporates is US$ 7.2–12.6 billion under RCP 2.6, and US$ 35.8–62.6 billion under RCP 8.5.


Dr Patrycja Klusak is an Associate Professor at Norwich Business School at University of East Anglia and an Affiliated Researcher at Bennett Institute for Public Policy at the University of Cambridge. Her research investigates the behaviour and regulation of credit ratings agencies (CRAs), and their effects on financial systems. Her work evaluates the extent to which regulations achieve their aims, or whether they lead to unintended consequences.

Her research also examines the relationship between firms' financial flexibility and their ratings, the extent of herding behaviour by CRAs, potential conflicts of interests in the CRA industry, and the effect of environmental, social, and governance (ESG) metrics on firm ratings. Her interdisciplinary work combines climate science and environmental economics with her expertise in empirical banking and applied econometrics to investigate how climate change risks have and could affect sovereign ratings.

The seminar will be held in English.

More information: Prof. Lorenzo Dal Maso