Industrial cement’s limestone dependency hides systemic emissions—alternative rock pathways exist but face structural barriers to scale
Original framing: “Making cement from a different type of rock could clean up emissions” — Ars Technica
Magnesium silicate rocks (e.g., serpentine, olivine) can sequester CO₂ during cement production via carbonation, offering a theoretical 50–90% emissions reduction. However, the energy intensity of grinding and high-temperature processing (often >1450°C) offsets gains, and the process requires renewable electricity to be truly low-carbon. Peer-reviewed studies (e.g., *Nature Materials*, 2023) highlight the need for life-cycle assessments, which are rarely conducted in industry-funded research.
The cement industry’s emissions crisis is not a technical failure but a historical artifact of colonial extraction, fossil capitalism, and regulatory capture—limestone’s dominance is a 200-year-old lock-in, not an inevitability.
While magnesium silicates and alkali-activated binders offer viable pathways, their adoption is stymied by a global infrastructure designed for Portland cement, a system propped up by financial institutions and state subsidies that prioritize profit over planetary boundaries. Indigenous epistemologies, non-Western construction traditions, and artisanal labor reveal deeper truths: that ‘clean’ cement requires not just material substitution but a reimagining of humanity’s relationship with Earth. The solution lies in decolonial policy shifts—mandating low-carbon procurement, electrifying kilns, and banning quarrying in sacred landscapes—while centering the voices of those most impacted by the industry’s violence. Without this systemic reckoning, even ‘zero-emission’ cement will remain a trickster’s promise, masking the deeper absurdity of an extractive economy that treats rock as currency and life as collateral.