Gran Canaria scientists test concrete debris for ocean carbon capture

Scientists from the GEOMAR Helmholtz Centre for Ocean Research Kiel are conducting experiments in Gran Canaria to test whether crushed concrete debris can enhance the ocean's ability to absorb atmospheric carbon dioxide.

The method aims to accelerate a natural process known as weathering, where minerals like calcium oxide in rocks increase seawater alkalinity and raise its pH, prompting higher CO2 absorption. Researchers estimate that one ton of cement dust could enable the ocean to absorb an additional ton of CO2. Given that approximately 5 billion tons of concrete waste are generated globally each year, the project explores a potential way to repurpose construction debris for climate mitigation.

The study utilizes twelve enclosed mesocosms to observe how marine organisms, such as plankton, react to varying concentrations of crushed cement. A primary focus of the research is determining environmental safety and ensuring that the intervention does not cross ecological thresholds that could harm marine biodiversity.