Global water crises – from drought in the world’s most productive farmlands to the hundreds of millions of people without access to safe drinking water – are the biggest threat facing the planet over the next decade.

This is the sobering finding of the World Economic Forum’s Global Risks 2015 report. It is not only the fourth time water has made the annual list that ranks the greatest risks to economies, environments and people, but the first time that water has moved into the top position for impact.

Other risks that made the list are inextricably tied to water management, access, sanitation, equity, health and ecosystems. They include: extreme weather events; failure of national governance, state collapse or crisis; rapid and massive spread of infectious diseases; and failure of climate change adaptation. Interstate conflict with regional consequences is the biggest risk in terms of likelihood. It is easy to see the links. Simply turn to just a few of the top stories of 2014:

Water connects, it doesn’t separate – what manifests itself as a regional or local crisis quickly becomes a global problem. Water crises affect economies of all sizes.

Roughly one-third of the world’s population now lives in water-stressed areas, and nearly a billion people still live without access to safe drinking water. Depleted reservoirs and dusty river beds are obvious symptoms, but another piece of the water puzzle is unseen below our feet. More than 95% of Earth’s liquid freshwater is stored in underground aquifers, and this groundwater is being used far more quickly than it is being replenished.

Nearly all of the world’s most productive farm regions – California’s Central Valley, the North China Plain, northern India, and America’s Great Plains – are overdrawing these foundational water assets. The World Bank predicts that global food production will need to increase by 50% by 2050. Considering that agriculture accounts for about 70% of global water consumption, the consequences could quickly become dire.

The current drought in California is a glimpse into this potentially drier future. After three years of parched conditions, water levels in nearly all monitoring wells in the state are at record lows. Many have dropped more than 15 metres in the last year alone. Even in years with normal rainfall, more water is taken out than replaced, and hundreds of families in the Central Valley lost running water to their homes last summer when the aquifer level fell below the reach of their wells.

A groundwater crisis also afflicts many of the world’s megacities. Dhaka, Houston, Jakarta and Mexico City are a handful of the urban centres that are pumping so much groundwater that the very land they occupy is collapsing. Jakarta has sunk 4 metres within the span of a generation. This geological subsidence changes a delicate balance, affecting everything from drinking water to essential support systems.

Beyond water for food and drink, increasing manufacturing and consumer markets are heightening the demand for water to produce electricity, mine minerals, make products and process fuel. The International Energy Agency projects that within the next 20 years, water consumption for generating energy will need to increase by 85%.

The hydrologic system is tied to climate, and climate change will profoundly affect water security worldwide. Droughts, floods, glacial melt, unpredictable precipitation, runoff, groundwater supplies and water quality will all reflect an increasing instability as long-standing rainfall patterns change and weather extremes increase. Global Risks 2015 says that the nexus of water, food, energy and climate change “is one of the overarching megatrends that will shape the world in 2030.”

Redirecting a disastrous trend

Shifting these dangerous trends involves courageous, informed, transparent and decisive action. Fortunately, from satellites to remote sensors, we have never had finer tools for measuring, charting and understanding the world’s water resources.

In agriculture, soil probes sense moisture levels for more effective irrigation and research is helping growers to better match crops, techniques and watershed management to hydrological conditions. In cities, membrane technology is creating new capabilities to transform wastewater into drinking water. Improved economic modelling is demonstrating the true value of ecosystems, which can offer greener, cleaner and more cost-efficient water processing and protection. Naturally.

But however promising our technologies may be, averting the most severe effects of the expanding water crises requires leaders who recognize the risk of inaction. “Decision-makers will be forced to make tough choices about allocations of water that will impact users across the economy,” asserts the report.

Difficult choices demand tenacious and renewed resolve, the report notes. “While this highlights a recognition of the importance of these slow-burning issues, strikingly little progress has been made to address them in light of their far-reaching and detrimental consequences for this and future generations.”

With consensus on the status of water as the major global risk for impact, the international community now has the clear mandate and obligation to act together. The United Nations this year will consider a new global development framework and a sustainable development goal for water. This goal would include improvements in sanitation and drinking water quality, but would also address how water is managed and governed.

There is progress. Companies, NGOs and governments are working together to protect watersheds, design more resilient cities and improve efficiency. Water withdrawals in the United States as a whole peaked in 1980 and have trended downward ever since. In Australia, after a devastating drought in the 2000s, cities there have cut water consumption by as much as 40%. Effective water, sanitation and health programmes in developing countries are saving lives and building better futures for families.

The solution, no matter where in the world, will be a mosaic made up of different vital pieces.

So it can be done, from the United Nations Sustainable Development Goals to collaborative management of groundwater, surface water and watersheds. Understanding the urgency and our high level of risk while embracing our shared values should drive informed action in times of tumultuous change. Investing in our water future now will yield dividends that are incalculable, and most certainly critical. One reason water belongs at the top of the agenda is simple: failure is not an option.

The Global Risks 2015 report is now live.

Authors: Peter Brabeck-Letmathe is Chairman of the 2030 Water Resources Group and Chairman of Nestlé SA. Carl Ganter is Founder and Director of Circle of Blue, which reports on the intersection between water, food and energy globally. They are both members of the World Economic Forum Global Agenda Council on Water

Image: Aerial view of the Central Arizona Project, designed to bring about 1.5 million acre-feet of Colorado River water per year to Pima, Pinal and Maricopa counties. Carl Ganter