Emissions from the cement and steel sector will continue blowing past their carbon budgets, hindering warming targets

The recent COP28 summit in Dubai reverberated with the urgency of climate action. Amidst the flurry of discussions, a critical question emerged: can we build a sustainable future without rethinking the very materials that form the foundation of our societies? Unfortunately for the cement and steel sector, a new study says no.

Large-scale carbon capture, utilisation and storage (CCUS) infrastructure have often been touted as a magic bullet to address the hefty carbon footprint of steel and cement — the very lifeblood of modern infrastructure.

However, recent research has discovered a yawning gap between projected and actual deployment of CCUS infrastructure. For starters, while the International Energy Agency's (IEA) rosy 2010 scenario envisioned capturing and storing nearly 200 million metric tons of CO2 from steel and cement industries by 2021, we've only managed to lock away a meager 1 million metric tons, casting serious doubt on the IEA's projected 2000 million metric tons by 2050.

The study's projections, based on historical trends and current construction plans, paint an even bleaker picture. The feasible supply of steel within carbon budgets compliant with the Paris Agreement will fall short of the projected demand by about 35-42%, despite substantial growth in recycling and hydrogen-based production. Cement supply is even more uncertain since it has even more limited mitigation options, and will fall short of decarbonising demands by a massive 44-78%.

"We are not saying that the existing scenarios are physically or economically unrealistic," clarifies Dr Takuma Watari, lead author of the study. "But simply waiting for new infrastructure to emerge and solve all our problems away is a very risky way of tackling the problem, given the scale of the challenges and the limited timeframe."

The timeframe Watari is referring to is our ambitious goals to decarbonise by 2050, of course. But the fact remains that steel and cement are some of the most energy-intensive sectors worldwide. In India, they contribute to about half of India's industry-related CO2 emissions. So, how do we cope?

Quantifying the scale of the required shift, the study proposes a benchmark: to adhere to Paris Agreement budgets, construction and manufacturing must use 60% and 40% less material, respectively. This is a massive change, especially for developing countries just starting to build wind underneath their feet, but a supremely important one in our current climate crisis.

"The construction and manufacturing industries will have to provide the same level of services with less material by changing the way products are designed, used, and disposed of," Watari adds.

Amidst these challenges, a silver lining emerges. The feasible supply, while insufficient for unbridled material consumption, can adequately meet the basic needs of a growing global population. The study highlights that global material demand for basic necessities like electricity, water, sanitation, shelter, and mobility falls well within the estimated feasible supply.

The road ahead requires collective action from governments, industries, and individuals. By acknowledging the limitations of current approaches and embracing innovative solutions, we can ensure that the materials that shape our world do not come at the cost of our shared future. However, as brought up multiple times at the COP28 conference, developed nations will need to shoulder a larger share of the responsibility.

"The challenge is more about equitable distribution than total quantity," emphasises Watari. "We recommend a greater responsibility be placed on high-income countries, which have much larger in-use material stocks than low-income countries."

The findings of this research have been published in Nature Communications and can be accessed here.