Summary

Abstract

We propose a statistical methodology to quantify the financial implications of tropical cyclone-related physical risks implied by climate change.  To address the sensitivity of  disaster  intensity  to  climate  change,  we  provide  a  Monte  Carlo  methodology  to generate synthetic cyclones consistent with climate scenarios of the Couple Model Intercomparison Project (CMIP5).  Sovereign exposure and vulnerability assessments in principal  tropical  cyclone  basins  are  based  on  projections  of  population  densities  in shared  socioeconomic  pathways  coupled  with  downscaled  physical  asset  values  constructed  using  mixed  data  along  with  locally  calibrated  damage  functions.   Finally, we compute the direct climate impact on emerging countries’ bond spreads using the spread sensitivity to the debt to GDP ratio, assuming that damage costs are financed by issuing new government debt. We find that the ‘business as usual’ RCP8.5 concentration scenario coupled with the ‘middle road’ shared socioeconomic pathway (SSP2) leads to global average annual damages 142% larger than in the concentration scenario RCP2.6 allowing to remain under 2°C warming.  In terms of emerging market impact, we estimate that in 2070-2100, the impact of extreme cyclones on the bond spread of most vulnerable countries will up to 200 bps higher in the RCP8.5 pathway than in the 2°C baseline.  In every step of our assessment, we quantify the impact of model uncertainty on our results using 7 different climate models from the CMIP5 database.

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Authors

Theo LE GUENEDAL
Quantitative Research, Amundi Technology
LMD-IPSL, Ecole polytechnique - IP Paris, ENS - PSL Université, Sorbonne Université, CNRS
CREST-ENSAE, IP Paris