A green-gray path to global water security and sustainable infrastructure

Liu, Hongxing; Bunn, S. E.; Bhaduri, A.; Stifel, David C.; Stewart-Koster, B.; Green, P. A.; Sadoff, C.; Wiberg, D. A.; Vörösmarty, C. J.; McIntyre, P. B.; Boone, E. K.; Flörke, M.; Fischer, G.

A green-gray path to global water security and sustainable infrastructure

Abstract

Sustainable development demands reliable water resources, yet traditional water management has broadly failed to avoid environmental degradation and contain infrastructure costs. We explore the global-scale feasibility of combining natural capital with engineering-based (green-gray) approaches to meet water security threats over the 21st century. Threats to water resource systems are projected to rise throughout this period, together with a significant expansion in engineering deployments and progressive loss of natural capital. In many parts of the world, strong path dependencies are projected to arise from the legacy of prior environmental degradation that constrains future water management to a heavy reliance on engineering-based approaches. Elsewhere, retaining existing stocks of natural capital creates opportunities to employ blended green-gray water infrastructure. By 2050, annual engineering expenditures are projected to triple to $2.3 trillion, invested mainly in developing economies. In contrast, preserving natural capital for threat suppression represents a potential $3.0 trillion in avoided replacement costs by mid-century. Society pays a premium whenever these nature-based assets are lost, as the engineering costs necessary to achieve an equivalent level of threat management are, on average, twice as expensive. Countries projected to rapidly expand their engineering investments while losing natural capital will be most constrained in realizing green-gray water management. The situation is expected to be most restrictive across the developing world, where the economic, technical, and governance capacities to overcome such challenges remain limited. Our results demonstrate that policies that support blended green-gray approaches offer a pathway to future global water security but will require a strategic commitment to preserving natural capital. Absent such stewardship, the costs of water resource infrastructure and services will likely rise substantially and frustrate efforts to attain universal and sustainable water security.

Title	A green-gray path to global water security and sustainable infrastructure
Creator	Liu, Hongxing
	Bunn, S. E.
	Bhaduri, A.
	Stifel, David C.
	Stewart-Koster, B.
	Green, P. A.
	Sadoff, C.
	Wiberg, D. A.
	Vörösmarty, C. J.
	McIntyre, P. B.
	Boone, E. K.
	Flörke, M.
	Fischer, G.
Publisher	Global Environmental Change
Academic Department	Economics
Division	Social Sciences
Organization	Lafayette College
Date Issued	September 2021
Date Available	2021-09-20
Type	Article
Language	English
Keyword	Water security
	Sustainable infrastructure
	Sustainable development
	Ecosystem services
	Nature-based solutions
	Water management
Bibliographic Citation	Vörösmarty, C. J., et al. (2021 Sept) "A green-gray path to global water security and sustainable infrastructure." Global Environmental Change 70: 102344.
Standard Identifier	Handle 10385/3197xn48t
Standard Identifier	DOI 10.1016/j.gloenvcha.2021.102344
Permalink	http://hdl.handle.net/10385/3197xn48t
Rights Statement	Creative Commons - Attribution
Rights Holders	Flörke, M.
	Bunn, S. E.
	Fischer, G.
	Stifel, David C.
	Stewart-Koster, B.
	Green, P. A.
	Sadoff, C.
	Wiberg, D. A.
	Vörösmarty, C. J.
	McIntyre, P. B.
	Boone, E. K.
	Liu, Hongxing
	Bhaduri, A.