For the first time, it is now possible to measure how long CO₂ is stored in biochar. A new method developed by researchers from Aarhus University and GEUS has been adopted by the EU as a common standard for certifying carbon removal.The method has been developed by a research team including Professor Hamed Sanei from the Department of Geoscience at Aarhus University, who is also the lead author of the scientific article underlying the work.The new method is based on reflectance analysis of the material combined with chemical investigations.

The analysis can determine how much of the carbon in biochar has been transformed into highly stable structuresknown as inertinitewhich can remain stable in nature for thousands of years.

Until now, the carbon storage potential of biochar has primarily been estimated based on theoretical calculations.

According to Hamed Sanei, the method represents an important shift:
“For the first time, certification of carbon removal at the EU level is based on direct physical evidence of carbon stability. This is crucial for credibility, trust in the market, and the long-term integrity of climate policy.” 

The certification scheme is voluntary but is expected to have global implications. It can help ensure that carbon credits purchased by companies to offset their own CO₂ emissions are based on documented and durable carbon reductions rather than uncertain estimates. In this way, it may help reduce the risk of greenwashing.