The reality of implementing FAIR principles in the IPCC context to support open science and provide a citable platform to acknowledge the work of authors.

A new paradigm for Intergovernmental Panel on Climate Change (IPCC) Working Group I (WGI) data publication has been implemented.  IPCC Data Distribution Centre (DDC) partners at the Centre for Environmental Data Analysis (CEDA), the German Climate Computing Centre (DKRZ) and the Spanish Research Council (CSIC) have worked with the IPCC Technical Support Unit (TSU) for WGI to publish figure data from the Sixth Assessment Report (AR6). The work was guided by the IPCC Task Group on Data Support for Climate Change Assessments (TG-Data) recommendations for Open Science and FAIR data (making data Findable, Accessible, Interoperable, and Reusable) with a general aim to enhance the transparency and accessibility of AR6 outcomes.  We highlight the achievement of implementing FAIR for AR6 figure data and discuss the lessons learned on the road to FAIRness in the unique context of the IPCC.

• Findable - The CEDA catalogue record for each figure dataset enhances findability. Keywords can be easily searched. Records are organised into collections for each AR6 chapter. There is a two-way link between the catalogue record and the figure on the AR6 website. CEDA catalogue records are duplicated on the IPCC-DDC. 
• Accessible - Scientific language is understandable, acronyms and specific terminology are fully explained. CEDA services provide tools to access and download the data. 
• Interoperable - Where possible data variables follow standard file format conventions such as CF-netCDF and have standard names, where this is not feasible readme files describe the file structure and content. 
• Reusable - The data can be reused, shared and adapted elsewhere, with credit, under a Creative Commons Attribution 4.0 licence (CC BY 4.0). Catalogue records link to relevant documentation such as the Digital Object Identifier (DOI) for the code and other supplementary information. The code used to create the figures allows users to reproduce the figures from the report independently. 

CEDA catalogue records provide a platform to acknowledge the specific work of IPCC authors and dataset creators whose work supports the scientific basis of AR6. 

Catalogue records for figure datasets were created at CEDA with data archived in the CEDA repository and the corresponding code stored on GitHub and referenced via Zenodo.  For instances where the data and code were blended in a processing chain that could not be easily separated, we developed criteria to categorise the different blends of data and code and created a decision tree to decide how best to archive them. Key intermediate datasets were also archived at CEDA.

Careful definition of metadata requirements at the beginning of the archival process is important for handling the diversity of IPCC figure data which includes data derived from climate model simulations, historical observations and other sources of climate information. The reality of the implementation meant that processes for gathering data and information from authors were specified later in the preparation of AR6. This presented challenges with data management workflows and the separation of figure datasets from the intermediate data and code that generated them. 

We present recommendations for AR7 and scaling up this work in a feasible way.