STORYLINE; 50°C IN PARIS

Methodology to determine when in the future extreme heat events above a chosen threshold become likely in cities, and to present the meteorological conditions that lead up to it.

Description

The City of Paris prepared an action plan for extreme heat and asked IPSL on the climate and meteorological conditions that could lead to temperatures exceeding 50°C in Paris.

We probed the entire CMIP6 archive (including several scenarios of emissions) to seek such events. We showed that such an event is virtually impossible in SSP1-2.6, if global temperature increase is kept under 2°C. This event becomes highly possible by 2050, if global temperature increase is larger than 2.5°C.

This study can be transposed to other regions of the world. A French new start up company is working on the code optimization, and on its application to other regions, and other climate variables.

Potential User Groups

Urban planners

Guide

An overview and application of the tool is provided in the paper:

Yiou, P., R. Vautard, Y. Robin, N. de Noblet-Ducoudré, F. D’Andrea, and R. Noyelle, 2024: How could 50 °C be reached in Paris: Analyzing the CMIP6 ensemble to design storylines for adaptation. Climate Services, 36, 100518, https://doi.org/10.1016/j.cliser.2024.100518.

Availability

Code including some guidance on how to use it on github: https://github.com/pascalyiou/Paris50C

Use Cases

Note for the city of Paris (in French) https://grec-idf.eu/simulations-paris-50c/

Reference

This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 101003469.

Tools

Importance Sampling

Importance sampling is a way to preferentially select out of a range of model simulations the ones that will lead to extremes of the metric of interest in an early stage of simulation, thus increasing computing efficiency for the cases of interest.

Étiqueté Tool