Over recent weeks, my colleague Gerry Gillespie and I have been in constructive discussion with senior executives at the United Nations Environment Programme (UNEP) about a deceptively simple question: what does “zero waste” actually mean?

This conversation did not arise in a vacuum. Turkey has adopted zero waste as a national strategy and is working closely with the United Nations in advancing that agenda. A major international zero waste event is scheduled for June as part of the build-up to COP31, which Turkey will host later this year. At the same time, colleagues within our network, including Gillespie, are in dialogue with COP31 leadership in Australia, where Minister Chris Bowen has been designated to preside over the negotiations.

In that context, clarity of definition becomes more than an academic issue. It becomes central to the credibility and effectiveness of international policy.

The discussion with UNEP was both agreeable and encouraging. There was clear recognition that multiple interpretations of “zero waste” are currently in circulation, and that this lack of clarity risks undermining progress at precisely the moment when global action is accelerating.

At the heart of the discussion was the definition developed by the Zero Waste International Alliance (ZWIA), which states plainly that zero waste means the progressive elimination of waste through the redesign of products, materials and systems. In other words, waste is not something to be managed better - it is something to be designed out altogether.

This stands in contrast to other commonly used interpretations. One is the notion of “zero waste to landfill”, which diverts materials away from landfill but continues to rely heavily on incineration and other disposal technologies. Another is the increasingly loose use of the term “zero waste” as a general aspiration, applied in ways that allow business-as-usual waste systems to continue largely unchanged.

Why the distinction matters

Systems built around disposal - whether landfill or incineration - lock us into a linear economic model based on extraction, consumption and discard. By contrast, a definition grounded in waste elimination forces a different kind of thinking: one that leads naturally to a circular economy in which materials remain in productive use.

What was particularly striking in our exchange with UNEP colleagues was the degree of alignment between this definition and the United Nations Sustainable Development Goals (SDGs). Whether the focus is on climate stability, ecosystem protection, resource efficiency or human health, the direction of travel is clear: reducing waste generation is fundamental to achieving all of them.

Put simply, a world that continues to produce waste at scale is not a sustainable world.

This is why clarity of definition now becomes critical. If the term “zero waste” is to be used within international policy and guidance, it must describe an end state that is consistent with the SDGs. The ZWIA definition does exactly that. It sets a clear objective - waste elimination - and aligns directly with the systemic changes required.

Timelines and proof of concept

An equally important point emerged from the discussion: the need for timelines.

It is not enough to define the destination; we must also establish a credible pathway to reach it. Countries and regions will start from very different positions, but without a shared sense of direction and a timeframe for transition, “zero waste” risks becoming yet another well-meaning but ultimately vague aspiration.

Experience shows that rapid progress is possible when clear targets are set. Wales, for example, has moved from recycling rates of around three per cent at the turn of the century to becoming one of the highest-performing recycling nations in the world within a single generation. That progress did not happen by accident - it was driven by policy clarity, public engagement and systems designed around source separation and material quality.

Another area of strong agreement was the importance of organic waste. In many parts of the world, organic materials make up more than half of municipal waste streams. Returning these materials to soil through composting and other biological processes reduces methane emissions, restores soil health, improves water retention and strengthens food systems. It is one of the clearest examples of how a zero waste approach aligns environmental, economic and social outcomes.

What UNEP brings to this conversation is not regulatory power, but something arguably just as influential: global leadership and the ability to set direction. By providing clarity on the meaning of zero waste, and by encouraging governments to adopt pathways toward waste elimination, the United Nations can help ensure that the term drives real change rather than diluted compromise.

The principles underpinning zero waste - reduce, redesign, reuse, and return materials safely to natural systems - are increasingly reflected in global thinking. The task now is to remove the ambiguity.

If “zero waste” is allowed to mean everything, it will achieve very little. If it is understood, consistently, as the elimination of waste, it becomes a powerful organising principle for the transition to a circular economy.

That is not an abstract ambition. It is a practical, achievable direction of travel - one that Wales and many communities and countries are already beginning to demonstrate.

The question is whether we are prepared to be clear about it. The resistance to change in waste management practices is strong, because waste creation underpins the linear, extractive economy that has been the foundation of economic growth since before the Industrial Revolution and is now accelerating exponentially year on year. Accelerating to such an extent that it now threatens our very existence on this planet.

Zeroing waste would be a good first step to putting the brakes on.