The ember factory

The purpose of this application is to (re)produce burning ember diagrams of the style used in IPCC reports. The code is open-source and available here: WARNING: this is a legacy version, in case of problems with the new one. See current version.

This application is written in Python, with the help of the ReportLab library (the web part is powered by the flask framework). The code is open-source and is available here: The ability of this application to reproduce several figures (independently) published by the IPCC was carefully tested. However, this is not a product of the IPCC (which is not responsible for projects or researches).


Although the web application and layout details were improved over time, there is no change affecting the translation of the risk levels provided as input to colours in the burning embers. The changes are recorded on A short summary is provided below.

2020/08: Median value in the transitions and better handling of input file issues

An optinal median, or 'midpoint' between the start and end of each transition, is added in the 'Basic format'. This results in the 'standard template' provided in Examples and documentation. Input files containing missing data, errors, or other unexpected characteristics are better handled, through workarounds and/or improved feedback messages to users.

Development history

This software was created by philippe.marbaix -at- at the end of 2019. The first objective was to produce figure 3 of Zommers et al. (2020; Burning Embers: Towards more transparent and robust climate change risk assessments. Nature Reviews Earth & Environment.
Help is welcome to further improve the application. All contributions will be recognised :-).

For more information, please e-mail philippe.marbaix -at-