Introduction

Climate change represents the defining environmental and economic challenge of the twenty-first century. Driven by greenhouse gas emissions from human activities, rising global temperatures are intensifying extreme weather events, biodiversity loss, and disruptions to food and water systems (IPCC, 2023). (1) Intergovernmental Panel on Climate Change (IPCC). (2023). Climate Change 2023: Synthesis Report. Contribution of Working Groups I, II and III to the Sixth Assessment Report. Geneva: https://www.ipcc.ch/report/ar6/syr/? The economic consequences are equally severe, with the International Monetary Fund and World Bank highlighting dual risks to global financial stability: physical risks such as infrastructure destruction and declining productivity, and transition risks arising from stranded fossil fuel assets. Without additional climate action, the Organisation for Economic Co-operation and Development (OECD) has estimated that these impacts could reduce global gross domestic products (GDP) by 1.0–3.3% by 2060, with disproportionately larger losses in developing regions (OECD, 2015). (2) Organisation for Economic Co–operation and Development (OECD). (2015). The Economic Consequences of Climate Change. OECD Publishing. https://doi.org/10.1787/9789264235410–en

Green technologies – innovations that reduce environmental impacts, improve resource efficiency, and lower greenhouse gas emissions – have emerged as a central pillar of global efforts to address climate change while driving economic growth and industrial transformation. The scale of this transition is significant: global investment in clean energy technologies reached approximately USD 2 trillion in 2024, surpassing fossil fuel investment for the first time, while the sector now employs an estimated 36 million people worldwide (IEA, 2024a; 2024b). (3) International Energy Agency (IEA). (2024a). World Energy Employment 2024. Paris: IEA. International Energy Agency (IEA). (2024b). World Energy Investment 2024. Paris: IEA. Frameworks such as the UK Green Financing Framework and the EU Taxonomy for Sustainable Activities reflect the growing alignment between green investment policy and technology classification.

As the green economy becomes a central focus of international policy and industrial strategy, understanding patterns of green technological innovation has become increasingly important for policymakers and researchers. Meaningful cross-country comparisons, however, require a coherent and transparent classification framework that is both analytically robust and internationally comparable – the foundational objective of this study.

This overview introduces the WIPO Green Technology Inventory for Statistical Use (WIPO-GTIS) – a new harmonized classification methodology developed through a systematic, consensus-based process. (4)The full study, WIPO IPC–Green Technology Concordance: A Harmonized Classification Methodology, can be accessed at https://www.wipo.int/en/web/ip-statistics/. Built strictly on an International Patent Classification (IPC)-Green Technology Concordance Table and validated through AI-assisted quality control, the WIPO-GTIS comprises five overarching sectors and 36 distinct technology fields. The methodology is designed to be accessible, requiring only IPC codes without keyword searches; transparent, as it is fully documented and reproducible; and robust, having undergone rigorous quality validation.