Public environment-related R&D expenditure has been more or less constant as a share of public R&D spending in OECD countries. The development and diffusion of environmental technologies, as measured through patent data, is generally increasing across countries in all areas of importance to green growth. Yet progress is uneven across countries, and is unlikely to deliver major changes in key environmental domains (OECD, 2014a). Given that a large majority of “green” innovations are developed in a small number of countries, achieving greater global diffusion will be essential.