Special coverage: The water transition

Water is becoming one of the defining challenges of the 21st century. The Water Transition argues that the future will belong to societies that create abundance rather than simply manage scarcity.

For generations, we've thought about water in much the same way. We found a river, built a dam, tapped an aquifer or extended another pipeline. As demand grew, we developed bigger infrastructure to move more water to where it was needed. It was a model that underpinned extraordinary economic growth and transformed communities around the world.

It was also a model built on one assumption: that nature would continue to provide.

That assumption no longer holds.

Across the world, climate change, population growth, industrial expansion and rising expectations are placing unprecedented pressure on the natural water systems that have sustained economies and communities for generations. Water is no longer simply an environmental issue or a utility service. It is becoming one of the defining economic challenges of the coming decades.

We are already seeing the economic consequences of water insecurity. GHD's Aquanomics report estimates that droughts, floods and storms could reduce global GDP by up to USD 5.6 trillion by 2050. That is no longer a distant environmental risk. It is a growing economic reality.

Yet despite this shift, much of the conversation remains trapped in yesterday's thinking. We continue to debate desalination versus recycling. We argue over water restrictions, new dams and infrastructure investment. These are important discussions, but they are not the fundamental question.

The real question is this: What kind of water system will a prosperous society need in the 21st century?

I believe the answer is to be found by acknowledging we are entering a Water Transition, much like the energy transition before it.

The energy transition challenged a century of assumptions about how we generate and use power. The Water Transition will do the same for one of our most fundamental resources. It asks us to move beyond simply extracting water from nature towards creating renewable, regenerative and adaptive water systems that strengthen economies while restoring the natural systems on which they, and all of us, ultimately depend.

It is not simply another infrastructure challenge. It is a new way of thinking about prosperity itself.

Every major infrastructure transition begins the same way. At first, the changes appear isolated. New technologies emerge. Regulations evolve. Investment patterns shift. Before long, it becomes clear that something much bigger is happening.

That is exactly where water stands today.

Around the world, governments are investing in potable reuse. Cities are turning to desalination to strengthen climate resilience. Industries are reducing demand and reducing risk through efficiency and recycling. Nature-based solutions are being integrated alongside traditional infrastructure. Investors are beginning to price water risk into long-term decisions, while insurers are paying closer attention to the resilience of water-dependent communities and industries.

These are not separate trends. They represent the functioning of an interconnected system, with water as the ultimate connector at its core.

Like the energy transition before it, this is not about replacing one technology with another. It is about changing the way we think about and the way we use an entire system. The renewable energy transition did not eliminate transmission networks, batteries or energy efficiency. It brought them together under a shared objective: creating a more resilient and sustainable energy system.

Desalination, recycling, water efficiency, nature-based solutions and better stewardship of our natural catchments are often presented as competing priorities. They are not. They are complementary tools that help build water systems capable of adapting to changing climates, growing populations and evolving community expectations.

This is where the principles of the circular economy become particularly valuable. Rather than continually extracting finite resources, the circular economy challenges us to retain value, recover resources and regenerate the systems on which future prosperity depends. Water fits naturally within that framework. Every litre conserved, reused, recycled or regenerated reduces pressure on natural systems while increasing the resilience of the communities and economies they support.

Seen through that lens, this transition is not simply about creating new water supplies.

It is about redesigning the entire water system to become more adaptive, renewable and ultimately more abundant.

For decades, much of the public conversation around water has been framed by scarcity.

We talk about running out of water. We introduce restrictions and belatedly make desperate investments during drought. We debate which communities should receive limited support, and which industries should use less. While these conversations are necessary, they also reinforce the idea that the future will inevitably involve managing decline.

I believe that is the wrong starting point.

The Water Transition should be built around abundance rather than scarcity.

Abundance does not mean unlimited water, nor does it ignore the realities of climate change. It means building systems capable of creating, recovering and renewing water so that economic growth no longer depends on continually drawing down finite natural resources, exceeding the limits of those systems, and damaging them.

That represents a profound change in ambition.

For generations, prosperity has largely depended on extracting more from the natural environment. This shift asks a different question: How do we create more water while giving more back?

That is where renewable water becomes such a powerful idea.

Just as renewable energy transformed the conversation from consuming finite fuels to generating cleaner energy, renewable water challenges us to move beyond managing shortages towards continually strengthening the systems that sustain communities, industries and ecosystems.

It is also a more optimistic conversation.

Scarcity tends to produce competition, restriction and short-term thinking. Abundance encourages innovation, investment and collaboration. It shifts the discussion from deciding who should receive less to asking how society can collectively create more.

That is not simply better public policy.

It is a stronger foundation for long-term economic prosperity.

If the Water Transition is already underway, an obvious question follows.

Why aren't we moving faster?

The answer is not a lack of technology.

Today's engineers have more tools available than at any point in history. Desalination continues to become more efficient. Advanced treatment technologies can produce drinking water from recycled sources that meets the highest standards. Digital systems are transforming how networks are monitored and managed. Nature-based solutions are increasingly complementing traditional infrastructure.

Yet many of the world's most promising water projects are delayed, scaled back or never proceed at all.

The barriers are increasingly social rather than technical.

Public trust, governance, funding models, regulation and political leadership often determine whether projects succeed long before engineering becomes the deciding factor. Communities ultimately need confidence not only in the technology itself, but also in the institutions responsible for delivering it.

There is also an economic choice. Are we prepared to invest in reliability and regeneration before scarcity forces our hand? That means deciding who pays, over what timeframe and how we value resilience before a crisis makes its value obvious.

We've solved many of the engineering problems.

Now we need to solve the human ones.

That means building stronger relationships with communities, developing governance systems that can respond to changing conditions and adopting planning approaches that recognise uncertainty rather than pretending it can be eliminated.

The future of water will be shaped as much by trust, leadership and adaptability as by engineering excellence.

For many years, sustainability has been the guiding ambition for water management.

It has encouraged better stewardship, improved efficiency and reduced environmental impacts. Those achievements should not be underestimated.

But the Water Transition asks us to go further.

There is an important difference between sustaining a system and regenerating it.

A sustainable system can be reached through slow decline, continuing until things can't get any worse. That point would then be sustainable – it stays the same. But it is not acceptable to me, nor is it to the community or our economy.

A regenerative system creates improvement. It restores ecosystems, replenishes natural resources and leaves future generations with stronger water systems than the ones we inherited. It is compatible with growth, creating equality and with meeting ambitions like the SDG6 targets.

That is a fundamentally different ambition.

It means measuring success not simply by how much water we conserve, but by how effectively we renew natural systems, strengthen communities and support long-term economic prosperity. It recognises that healthy rivers, resilient catchments and renewable water supplies are not environmental luxuries. They are productive assets that underpin future growth and prosperity for all.

If abundance defines the destination, regeneration defines how we get there.

Abundance is about creating enough renewable water to support prosperous communities and economies. Regeneration ensures that, in doing so, we also strengthen the natural systems on which that prosperity depends.

That is why I believe regeneration will become the defining measure of successful water systems over the coming decades.

The real legacy of this new model will not be the infrastructure we build.

Over the next decade, I believe we'll look back on this period as the moment our relationship with water fundamentally changed.

Water will no longer be viewed simply as a utility service or an environmental issue. It will be recognised as one of the defining foundations of economic resilience, shaping where industries invest, how cities grow and which communities prosper.

Most importantly, I believe the conversation will have changed. We will spend less time debating individual technologies and more time asking a much bigger question: How do we create water systems that leave the next generation better off than the one we inherited?

The future of water is not about choosing between desalination, recycling, efficiency or nature-based solutions. It is about understanding how each contributes to a broader transition towards renewable, regenerative and adaptive water systems.

The Water Transition has already begun.

The Water Transition is a Nexus thought leadership series exploring how renewable, regenerative and adaptive water systems can underpin long-term prosperity.

Over the coming months, this series will explore:

• The Water Transition: why abundance, not scarcity, must define the next decade (you’re here now)
• How the UK can get reuse and desalination right the first time
• Water governance and economic competitiveness
• The water transition: what water can learn from energy
• Adaptive water planning: why 100-year plans no longer work
• Desalination versus reuse is the wrong debate
• From sustainability to regeneration
• The data centre dilemma: who should pay for water security?
• Data centres are a wake-up for The Water Transition