Pezzey, John C.V.2025-05-302025-05-300095-0696WOS:001263480400001ORCID:/0000-0001-6473-9355/work/172014930http://www.scopus.com/inward/record.url?scp=85195674098&partnerID=8YFLogxKhttps://hdl.handle.net/1885/733755205We build a theoretical model of optimal, closed-economy growth of production and consumption, including inputs of human and knowledge capital and growing natural resources, and give two calibrations of it to the global economy's approximately exponential growth during 1995–2014. We thereby show that the World Bank's Adjusted Net Savings (ANS) measure of an economy's sustainability, which has some practical and theoretical advantages over change in wealth, the Bank's preferred measure, ideally needs further adjusting. Our model includes omitted or undervalued estimates of the benefits of human and knowledge capital investment, net resource growth, and productivity growth, and the cost of capitals dilution by population growth. Together these raise estimated, global ANS about 10 percentage points above the Bank's estimate, to equal their growth rate times total wealth, but our adjustments could be negative overall for some countries. By reclassifying about 18% of output from consumption to human and knowledge capital investments, our second calibration needs only 0.3 %/yr of exogenous productivity growth to explain global consumption growth observed during 1995–2014. Though our model omits environmental costs and thus ignores long-run sustainability issues, our adjustments suggest desirable though difficult changes that could improve World Bank ANS as a comparative sustainability indicator.For helpful comments I thank Geir Asheim, Giles Atkinson, Paul Burke, Barbara Fraumeni, Quentin Grafton, Frank Jotzo, Larry Liu, Rob Marks, Martin McCarthy, Warwick McKibbin, Rui Mota, Budy Resosudarmo, David Stern, Simone Valente, Rick van der Ploeg, Matthew Woolf, Rintaro Yamaguchi; participants at the 2021 Monash Environmental Economics Workshop, the 2022 Australasian Agricultural and Resource Economics Society's conference and the 2022 Sustainable Resource Use and Economic Dynamics conference; and two especially helpful anonymous referees, one of whom provided a draft ofAppendix C and detailed notes for Appendix E. I owe much to inspiration from work by Marty Weitzman and by Kirk Hamilton, who are both sadly missed. This research received no grant from funding agencies in the public, commercial, or not-for-profit sectors, and the author declares no conflict of interest. All errors and omissions are my own.20enPublisher Copyright: © 2024 The AuthorAdjusted Net SavingsConsumption growthGlobal sustainabilityHuman capitalPopulation growthResource discoverySustainability accountingTotal factor productivityWealthWorld Bank2024-04-3010.1016/j.jeem.2024.10298485195674098