The ember factory

Warning: this is a legacy version. The current version is here. The purpose of this application is to (re)produce burning ember diagrams. More information.

This page is the starting point to learn about the preparation of data for the 'Ember Factory'. It provide examples of input files with increasing flexibility.

To make 'ember' diagrams from your own data, start from the Basic format below, which contains a standard IPCC-style data table (note that no files are 'from the IPCC' or under its responsibility: see more information).

Section 1 below should cover most needs when you begin. If you face difficulties such overlapping text in your diagram, continue to section 2 about the layout parameters. Those parameters also allow for selecting and sorting embers from your data before plotting, or adding some types of information on the diagram. For more details about the parameters, see Parameters.

Basic format

We expect the Basic data format to fill most needs. It is simple and receives more development efforts. This format is based on tables provided in the supplementary material of IPCC Special reports published in 2019. The files indicate the level of global warming (or other 'hazard metric') which corresponds to "risk transitions", i.e. changes from one risk level to the next, according to a standard scale of risk used by the IPCC in several of its reports.

Files contain a main spreadsheet containing the ember data and optional metadata. Additional spreadsheets are optional and makes it possible to fine-tune the presentation of the embers diagram, as explained in the next sections. The main spreadsheet contains the following information:

SRCCL figure SPM.2 B

SRCCL example

This example contains the data from table SM7.6 of the Special Report on Climate change and Land. The resulting 'burning ember diagram' appears in the Summary for Policymakers as figure 2, panel B (IPCC website).

Template for new embers

Standard template

This spreadsheet does not contain real data, but rather generic names intended to help identifying how it can be modified.

In addition to the SRCCL example, this sheet contains lines to indicate the hazard level corresponding to the 'midpoints' (or median) within each transition. Those midpoints are optional. A given spreasheet may include transitions with or without midpoints.

Key parameters in the "data" spreadsheet

A few parameters, mainly related to the data itself, can be set in the same spreadsheet as the data. The most common ones are the following:

haz_axis_top The top value in the hazard axis
haz_name Name of the hazard variable (such as 'Global mean temperature'), used as axis name
haz_unit Unit of the hazard variable (added to the axis labels, except if already included in haz_name)

None of these parameters is mandatory: there are default values, for more information on the metadata and other parameters, see Parameters.

Basic format with a 'Graph parameters' sheet

The simpler files described in the previous section only provide access to a few parameters. They are sufficient to reproduce most types or 'burning ember' figures published so far, but with limitations regarding layout details. To avoid cluttering the sheet that contains the assessment data, we provide layout-related parameters in an additional sheet, which must be named "Graph parameters".

The result is still called the "basic format", because the ember data is decribed in the same way as above. If you started from a file presented in section 1, it is easy to add the layout parameters in your existing Excel file: download the example from this section and copy the "Graph parameters" spreadsheet in your existing file (in Excel, start from the downloaded example and right-click on the tab showing the Graph parameters spreadsheet). There is no need to include all parameters: a "Graph parameters" sheet including just one parameter would have this parameter taken into account and all others kept to their default values.

SRCCL example + layout

The "Basic+layout" example includes the additional 'layout' sheet with most (but not all) possible parameters. This particular example illustrates the following:

The resulting figure is significantly closer to the layout of the published figure (figure 2, panel B (IPCC website)); this shows the flexibility generated by using the 'Graph parameters' sheet.

There are other options illustrated in this Excel file, such as the possibility to sort the embers. This makes it possible to generate different diagrams without changing the 'data' sheet, by listing ember names in the desired order. See Parameters for more information.

Colour Palettes and colour models

If you do not have specific colour needs, keep the standard/defaults settings. The EmberFactory supports arbitrary colour palettes for the ember gradients. There are two ways to change colours:

Both RGB and CMYK colour palettes are available. However, if you use CMYK, beware that this will only be provided in the PDF files, as this colour model is not supported in PNG or JPEG files. For more information on colour palettes, please e-mail

Adding ember-specific metadata

Starting with version 1.4 of the EmberFactory, there is some support for metadata about each ember. This data is intended for future use (possibly outside the current user interface). Ember metadata is provided as additional columns at the right of the ember data, as shown in Example with ember metadata. Tentative metadata names are currently the following: Remarks, Description, Keywords, Long name, Inclusion level, References. It is not mandatory to provide a complete set of metadata, but names outside this list will produce a warning. For more information about future plans, please contact

Fullflex format

The "full flexibility" format provides more flexibilty regarding the input data. The first sheet from this Excel workbook is completely different from the first sheet of the 'basic format' above. It provides more control on the risk levels, e.g. a transition that has a faster increase in risk at some temperature level. The second sheet is the 'Graph parameters' sheet described above, and the last sheet defines the colors and associated risk levels. The fullflex format was developed for Zommers et al. [1].

Zommers et al. 2020

The data used in figure 3 of Zommers et al. [1] is available from; The approach for obtaining this data is decribed in Marbaix (2020).

Additionally, RFCs-data-2020_01_26-Z2020_rev1_byPubli.xlsx shows the embers sorted by publication (instead of by Reason for concern). Both files contain the same data, while the different sorting is triggered by parameters in the 'layout' spreadsheet.

[1] Zommers, Z., Marbaix P, Fischlin A., Ibrahim Z. Z., Grant Z, Magnan A. K., Pörtner H-O, Howden M., Calvin K., Warner K., Thiery W., Sebesvari Z., Davin E. L., Evans J.P., Rosenzweig, C., O’Neill B. C., Anand Patwardhan, Warren R., van Aalst M. K. and Hulbert M. (2020). Burning Embers: Towards more transparent and robust climate change risk assessments. Nature Reviews Earth & Environment.

It did not work! Why?

The Ember Factory is tested on several figures. However, it might be that you created an input file that includes something that we missed. We make efforts to deal with a variety of cases that may produce a diagram as well as with cases of "malformed inputs". If you received error messages, have a look at these: does it show that the processing ended at a specific point, such as while reading or drawing one of your embers? If the list of parameters is already visible (it is produced at the roughly the middle of the process), a quick look may show you that some are not set as you would expect.

If you obtained a graphic, but it is not what you expected, you may click on "View / hide log information". This will show a list of processing steps including the value of all parameters which were used and information about the colour gradients for each ember.

In any case, reporting errors or unsatisfying results helps improving the software! Please drop an e-mail to (a title such as "EmberFactory issue" may help).

Further improvements & documentation

Comments are welcome. We will make our best to respond to requests regarding improvement, documentation, or specific features, adapting the application if needed. (see contact below).