This paper, authored by James Boyd and Spencer Banzhaf, advocates for the development of consistently defined units of account to measure the contributions of nature to human welfare. The authors argue that the term "ecosystem services" is too vague and ad hoc for practical use in welfare accounting. They propose a definition of ecosystem service units rooted in economic principles, aiming to make these units comparable to conventional goods and services in national accounts, such as GDP. The paper emphasizes the importance of clear and precise definitions for effective environmental procurement and accounting, particularly in the context of green GDP. It also discusses the challenges of measuring non-market goods and services, and provides a detailed inventory of ecosystem services, highlighting their spatial specificity and benefit-specific nature. The authors conclude by suggesting that their proposed definition of ecosystem services can be integrated into broader accounting frameworks to enhance the measurement of environmental quality and well-being.This paper, authored by James Boyd and Spencer Banzhaf, advocates for the development of consistently defined units of account to measure the contributions of nature to human welfare. The authors argue that the term "ecosystem services" is too vague and ad hoc for practical use in welfare accounting. They propose a definition of ecosystem service units rooted in economic principles, aiming to make these units comparable to conventional goods and services in national accounts, such as GDP. The paper emphasizes the importance of clear and precise definitions for effective environmental procurement and accounting, particularly in the context of green GDP. It also discusses the challenges of measuring non-market goods and services, and provides a detailed inventory of ecosystem services, highlighting their spatial specificity and benefit-specific nature. The authors conclude by suggesting that their proposed definition of ecosystem services can be integrated into broader accounting frameworks to enhance the measurement of environmental quality and well-being.