The boundaries between integrated assessment and sustainability action will continue to blur in the coming years. From rising temperatures and sea levels to disappearing forests and biodiversity, global integrated assessments are painting an increasingly bleak future for our planet. According to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC), global warming beyond the 1.5 °C mark in the coming decades presents considerable risks, including irreversible impacts to our societies, economies and ecosystems1. The political will to act finally seems to be catching up — net-zero targets have been adopted by more than 70 countries representing some 80% of greenhouse gas (GHG) emissions globally and the United Nations-coordinated Race to Zero initiative now includes over 1,000 cities, 5,000 firms and 400 financial institutions (https://www.un.org/en/climatechange/net-zero-coalition). With countries, cities and communities increasingly turning to science-informed actions, this will mark a turning point for the global integrated assessment communities.

The global integrated assessment communities, numbering hundreds of scientific groups across the world, use coupled biophysical and socioeconomic systems models to guide policies across sectors such as energy, agriculture, water, ecosystems and biodiversity (https://www.isimip.org/about/). Integrated science, which began in the 1980s, has responded to evolving policy demands for a greater integration of the human dimension2 and, more recently, knowledge co-production3. Research is currently active to improve the usability of integrated assessment, such as participatory modelling and scenario services4. However, such emphasis on the use of science alone will probably miss greater opportunities for reflexive learning. Here we summarize a few lessons learned regarding knowledge co-production and we identify the analytical frontiers of reflexivity.