The global water cycle is our planet's life-support system. It is a powerful environmental pump, with forests transpiring moisture and replenishing giant atmospheric rivers of freshwater. It is also a global thermostat, regulating the climate through evaporation and cloud formation. And it is a giant filter, purifying water as it percolates through the soils and wetlands.
But while all life depends on the water cycle, it is coming under increasing strain and losing its ability to perform these essential functions, leading the United Nations to declare a new era of "global water bankruptcy". Rising temperatures, ecosystem degradation, and shifting rainfall patterns are weakening the natural systems that regulate water flows and quality, while conventional infrastructure, designed for historical hydrological conditions, is increasingly exposed to variability, sedimentation, and shock.
To protect the water cycle from these competing pressures, we must embrace a holistic perspective. That means treating the cycle as shared infrastructure, and reshaping investments and governance accordingly.
As a first step towards protecting the natural infrastructure that has served us for centuries, governments, investors, and multilateral development banks should emphasise retaining water in its natural environment. Efforts to protect forests, wetlands, river basins, and soil cover are key to mitigating disruptions to the water cycle and adapting to shocks.
To be fully effective, such interventions should be conceived at the level of total ecosystems. For example, the Delta Blue Carbon project has facilitated the planting of tens of millions of mangrove seedlings on the southeast coast of the province of Sindh, Pakistan, restoring more than 75,000 hectares of degraded mangrove forests. Such efforts are projected to sequester 142 million tonnes of carbon dioxide over the next five decades, as well as protect against storm surges and provide nurseries for marine biodiversity.
Beyond restoring the natural (green) infrastructure that we already rely on, we must also pursue traditional (grey) infrastructure investments to build water-system resilience against higher temperatures, glacial melts, and more volatile climate conditions. For example, the Indonesia Dam project aims to strengthen buffers against floods and preserve key sources of water supply. It combines engineering measures, such as dredging and structural rehabilitation, with ecosystem restoration to address sediment accumulation and its consequences.
This combination of green and grey infrastructure has the potential to support mitigation and adaptation efforts to protect the water cycle against climate change. But bringing them together requires alignment on governance, data, and finance.
From a governance standpoint, water is too often treated as a local commodity, rather than as the shared, transboundary resource that it is. Fortunately, emerging science and technology could transform water governance by allowing the tracking of individual drops of water. Satellite data, remote sensing, and improved modelling already allow for real-time monitoring of water flows, infrastructure performance, and environmental conditions. And now, AI and machine learning can improve flood forecasting, optimise irrigation scheduling, and support predictive maintenance.
Moreover, leveraging these technologies to improve water governance will lay the groundwork for scaling up investment in the hydrological cycle -- and not a moment too soon. As matters stand, an estimated $7 trillion is needed to close the gap for investment in water infrastructure by 2030.
Multilateral development banks have an important role to play in mobilising finance towards water-cycle preservation. The AIIB finds that water-related projects account for a decreasing share (around 14%) of dwindling overall official development assistance. It is therefore imperative that development banks boost their investments across the water cycle to integrate natural, engineered, and digital infrastructure; promote economic reforms to align fiscal policies across borders; and mobilise private finance towards water-focused interventions.
As we look towards a more uncertain, insecure water future, it is incumbent on governments and financial institutions to ensure that restoring and maintaining our water cycle is a key development priority. We must come together to harness recent advances in science, monitoring technologies, and data availability to improve governance and scale up financing. Water is the foundation that connects every aspect of human life. There can be no higher priority than protecting the water cycle. ©2026 Project Syndicate
Erik Berglöf is Chief Economist of the Asian Infrastructure Investment Bank.
