The Organisation for Economic and Cultural Development (OECD) works with countries worldwide to implement testing in the areas of science, mathematics and reading through the Programme for International Student Assessment (PISA) every three years, and this process is recognised to influence education systems through areas such as curriculum. Over the past decade, the OECD increasingly has acknowledged the need to include a greater emphasis on environmental issues, including developing student competencies specifically in this area. For the 2025 PISA round, we were invited as environmental science education experts to contribute to the Science Framework, which underpins the science assessment. This paper explains how we responded to that invitation, including foregrounding the urgent need to understand the competencies of 15 year-olds to address critical socio-ecological challenges such as climate change. We argue that this provides environmental education practitioners and scholars with a powerful opportunity to gain world-scale data for research and advocacy, which could enhance the visibility and leverage for our field in curriculum, whilst also recognising the political process within which we were engaged.