Farm waste could lock away carbon for decades

Agricultural waste that is usually burned or left to rot could play a far bigger role in tackling climate change if it were instead used in long-lasting building materials, according to new research from the University of East London (UEL).

The study shows that fibrous residues from crops such as wheat, rice and maize - produced in billions of tonnes every year worldwide - could act as a powerful carbon sink when diverted into construction products like insulation, boards and panels. Rather than releasing carbon back into the atmosphere within months, these materials can store it for decades.

Led by Dr Bamdad Ayati from UEL’s world-leading Sustainability Research Institute (SRI), the research is one of the first to assess this opportunity at a global scale using a “dynamic” life-cycle approach. Unlike conventional carbon accounting methods, the analysis tracks when carbon is released or stored over time, revealing how timing can significantly change the climate impact.

The findings suggest that simply stopping the open burning of agricultural residues and redirecting them into long-lived building products could deliver a sustained cooling effect over the next century. When paired with renewable energy to replace displaced biomass energy use, the climate benefits become even stronger.

The research also highlights a mismatch between the scale of available biomass and how little of it is currently used in durable products. While around 4.4 billion tonnes of agricultural residues are generated each year, only a small fraction is used in long-lived applications, with most being burned, used as animal feed, or left to decay.

Crucially, the study shows that even ambitious growth in bio-based insulation alone would only absorb a small share of this material. To unlock the full climate potential, the authors argue, the construction sector needs to expand the use of bio-based materials beyond niche applications.

Dr Ayati said the work points to an overlooked climate opportunity hiding in plain sight.

“Each year, large volumes of agricultural residues are burned or left to decompose, returning carbon to the atmosphere within a short time,” he said. “Our research shows that if these fibres are redirected into long-lived building materials, they can store carbon for decades and produce a measurable cooling effect. This reframes residues from a disposal issue to a potential climate resource.”

The study, “Dynamic life cycle assessment of fibrous agricultural residues for long-lived carbon storage in building materials”, was published in the journal Cleaner Environmental Systems and involved researchers from UEL’s Sustainability Research Institute and School of Architecture, Computing and Engineering.