Breaking the habit of a lifetime: Embracing sustainable alternatives to Portland cement

The COP29 climate summit underscored a troubling paradox in global sustainability efforts: while innovation and ambition are celebrated in theory, they’re often stifled in practice by a fixation on incremental fixes rather than transformative change. This is especially apparent in the cement industry, where the reliance on Portland cement (OPC) and its carbon-heavy clinkering process persists, despite the availability of sustainable and innovative alternatives.

The cost of sticking with clinkering

OPC, the binder at the heart of most concrete, is the world’s second-most consumed substance after water. Its production, however, is a major culprit in climate change, responsible for almost 9% of global CO₂ emissions. The central process—clinkering, which involves heating limestone to extreme temperatures—has changed little in 200 years and remains a glaring inefficiency in an era demanding bold environmental solutions.

At COP29, the Global Cement and Concrete Association (GCCA) reiterated its commitment to reducing emissions, but the strategy proposed—a heavy reliance on carbon capture and storage (CCUS)—is emblematic of the industry’s refusal to address the root problem. CCUS is an energy-intensive and expensive stopgap, one that manages to capture only 0.1% of global emissions today. Instead of dismantling an outdated system, resources are funneled into retrofitting kilns that shouldn’t exist.

The math is clear: we cannot afford the time, cost, or complexity of leaning on CCUS as a viable long term solution. The cement industry needs a paradigm shift—one that rejects clinkering entirely and embraces a new generation of sustainable materials and processes.

Redefining cement and concrete

True progress in the construction industry starts with redefining what cement and concrete can be. The term “low-carbon cement,” as currently used, risks becoming a greenwashed label that rewards minor adjustments to an inherently unsustainable process. To drive real change, we need bold and precise standards that push the industry beyond incrementalism and toward transformative alternatives.

Take magnesium-based binders, for example. By deriving magnesium from brine, companies like Partanna avoid the need for limestone and the high-temperature kilns that define OPC production. Even better, this innovation enables concrete that actively removes CO₂ from the atmosphere, flipping the environmental script to make construction a carbon sink rather than a carbon source.

Similarly, bio-based concretes and microbial mineralization technologies demonstrate that nature-inspired solutions can outperform their fossil-fuel-intensive predecessors. These breakthroughs don’t just lower emissions—they eliminate them.

Scaling the solutions

The construction industry is often dismissed as slow-moving, but it doesn’t have to be. Innovations like Partanna’s carbon-negative concrete have already gained real-world traction, from projects in Saudi Arabia and the UAE to the United States and The Bahamas. Moreover, independent validation, such as certification by Verra, proves that these approaches aren’t just theoretical—they’re viable at scale.

Yet scaling such solutions requires systemic support. Governments and industry leaders must align to promote adoption through policy incentives, subsidies, and aggressive regulatory standards. Funding research and development is critical, as is creating a level playing field where genuinely sustainable alternatives can compete with the entrenched, heavily subsidized OPC industry.

Broader implications

The shift away from clinkering isn’t just an environmental imperative; it’s an opportunity to redefine construction as a force for good.

Imagine an industry that not only builds our cities but also cleans our air—a future where construction becomes part of the solution to climate change rather than a contributor to it. Our ethos at Partanna is always to delink development from pollution and we are showing it is possible. The stakes are enormous. The global cement market, worth $400 billion annually, represents a powerful lever for systemic change.

Material science – the new revolution in the cement sector

So let’s take an example of sustainable alternatives to OPC; magnesium based cements. The crucial core material required for a sustainable binder is Magnesium Oxide (MgO), that can be reclaimed from brine or other sources of salt water. Utilizing MgO, OPC can be banished from manufacturing processes.

In many ways there is nothing new about using MgO as the key ingredient for a sustainable binder. Both the Great Wall of China and the Roman Colosseum, were found to include traces of magnesia rich cement. But since ancient times, MgO has never really taken off and has long been overlooked.

For a few perceived reasons:

1. Significant costs associated with mining MgO from the ground in China
2. Magnesium's ability to rust rebar
3. Questions over the strength of MgO cement for structural uses

But these questions can be put to bed. Let’s take on those historically held assumptions:

The price is right

Sourcing MgO from brine is already being used around the world, enabling companies like Partanna to be price competitive with OPC in our key markets. Why? Because mining MgO and transporting it from China can drive up costs quickly. But we can now extract MgO from any location in the world, because brine or other sources of salty water is abundantly available, 71% of the world’s surface is salt water – this means the solution is scalable which has long been a question over alternatives to OPC.

A brine extraction plant that can be built within six months is the key infrastructure needed. Once that’s established, binder can be mixed and the local market can be supplied.

Strength in MgO

Our carbon-negative MgO binder has undergone rigorous third-party testing and evaluation, we meet conventional ASTM standards for concrete - US standards that are recognised around the world. Partanna can develop strengths of  up to12,000 PSI depending on the requirement from our customers. Moreover, concrete made with our binder does not rust rebar, as extensive testing has shown and our product is compatible with reinforcing steel. Questions over the strength of our product are therefore answered.

Take courage

Embracing a revolution in material science in the concrete sector requires courage. The GCCA, as a leading industry body, must lead by example, setting ambitious targets that prioritize transformative innovations over tweaks to existing processes. Anything less risks locking the sector into another century of climate irresponsibility.

This year marks the 200th anniversary of OPC’s invention. Rather than celebrating, we should be asking hard questions about its future. Do we continue burning limestone and calling it progress? Or do we break the cycle and embrace the sustainable alternatives already within reach?

The answer lies not in incremental tweaks but in bold action. The next generation of construction materials—carbon-negative concretes, bio-based binders, and other innovations—offer a clear path forward. The technology is here. The challenge is scaling it and integrating it into mainstream practices before it’s too late.

COP29 reminded us of the urgency of the climate crisis. It’s time for the concrete industry to rise to the occasion. Let’s leave clinkering behind and build a future that’s not just stronger, but greener. Together, we can turn construction from a climate problem into a climate solution.