A Nature study has poured cold water on the idea that bio‑based materials — including cross‑laminated timber, engineered bamboo and rammed earth — can replace concrete on an industrial scale, finding that they can meet less than 14 per cent of global housing demand under current sustainable-harvesting limits. And replacing concrete outright, the authors warn, would require timber harvesting to increase by more than tenfold, a scale they say is neither realistic nor sustainable.
Instead, the key is to combine different building typologies to develop fit-for-purpose solutions, as in Jiangsu Province, China, where the best of both worlds can be achieved. “Low‑carbon concrete is not perfect, but it is the lowest‑carbon option that can be scaled‑up to meet global demand by 2050,” the study said.
The global research, spanning five institutions (including the World Resources Institute in Washington), challenges the belief that mass timber and bamboo could fully replace low-carbon concrete in global construction. While these products are often promoted as climate‑friendly, the authors argue that most assessments “disregard resource availability and harvesting emissions.”
A key focus of the research is how carbon is counted.
The team uses “harvesting‑inclusive biogenic carbon accounting,” a method that assigns emissions from soil disturbance, roots, foliage and forest residues to the final product. This approach, they write, “accounts for the changes in different carbon pools,” including both regrowth and production emissions.
Other methods that often exclude harvesting impacts, such as timber and bamboo, appear to deliver strong carbon savings. But once harvesting is included, their footprints rise sharply — a shift the authors say must be acknowledged. Ignoring these impacts, they warn, can lead to “false conclusions… on the possibility of bio‑based materials buildings being carbon‑negative.”
The study also points to wide inconsistencies in published data, noting a “variation of 50% to −125% in the inventory data compared to the average carbon intensity,” driven by differences in factory efficiency and how residues are used or burned.
Beyond carbon, the researchers identified that supply is a major obstacle.
Between 2025 and 2050, they estimate that global forests could produce enough engineered timber and bamboo to meet just 13.7 per cent of projected urban housing demand. Even at maximum output, “this scenario… would still leave 86.3% of demand unfulfilled,” a shortfall of around 48 billion cubic metres of material. Closing that gap, they write, would require production levels “>10 times greater than the current global, annual timber production,” which is approximately 3.6 billion cubic metres a year — levels they describe as both logistically and socially unacceptable.
“From a global perspective, bio‑based materials could make a minor contribution, at most, to urban housing demand,” they said. And while mass timber may expand in regions with abundant forest resources, the authors warn that “under the pragmatic boundary conditions used in this study, such mass adoption appears unlikely to be feasible in practice… it can have very little impact before 2050.”
For more information: Hafez, H., Marsh, A.T.M., Flegar, M. et al. Low-carbon concrete has the potential to meet global urban housing needs by 2050. Commun. Sustain. 1, 28 (2026). https://doi.org/10.1038/s44458-025-00027-1.
