Green infrastructure as critical capital in the anthropocene

Abstract

Human societies are confronting converging pressures from climate instability, biodiversity loss and rapid urbanization that are particularly severe in tropical and subtropical regions. Heatwaves, erratic rainfall and landscape degradation increasingly expose the limitations of ageing concrete‑and‑steel grey infrastructure designed for stable climates and some that no longer exist. This Viewpoint article synthesizes economic valuations and benefit-cost analyses to demonstrate that components of natural ecosystems, such as mangroves, forests, and urban greening, function as high-performing critical green infrastructure. When deployed in the right contexts, these living systems frequently outperform or complement grey infrastructure as cost‑effective, flexible, and climate‑resilient services.

Drawing on case studies from the Global South, we show that investments in green infrastructure secure substantial economic and societal benefits compared with grey infrastructure. Mangrove restoration protects coastlines at two to five times lower cost. Forest conservation reduces water treatment and dredging costs. Urban greening reduces mortality and energy demand. Yet despite strong macroeconomic rationale, including potentially reducing regional GDP by up to 9.7% in Sub‑Saharan Africa and 6.5% in South Asia by 2030, investment remains limited.

This Viewpoint's “critical capital” framing integrates ecosystem components as infrastructure assets that can be valued, budgeted, and regulated within national planning systems. The Anthropocene is the analytical context because it is the condition under which grey infrastructure’s design assumptions collapse and the adaptive properties of living systems become economically decisive. The evidence presented here provides a logical basis for institutional reform by infrastructure planners, development finance institutions, and economic ministries in tropical middle-income countries.