Our new methodology builds an inter-country input-output table that distinguishes green products from the rest, allowing us to assess vulnerabilities in green value chains. In a multi-country, multi-sector model, our table reveals that a decoupling of green supply chains between a US-centric West and a China-centric East could globally cut trade in green products by up to 20%, lower welfare by up to 3% and raise yearly global greenhouse gas emissions by about 50 million tonnes.