8.4 bn tonnes of carbon estimated to be stored in technosphere

A study by researchers at the University of Groningen, Netherlands, revealed that between 1995 and 2019, approximately 8.4 billion tonnes of fossil carbon were stored in long-lasting human-made products like plastics and buildings. This “fossil carbon” within the “technosphere“—the sum of all human-made objects, both in use and discarded—represents about 93% of global carbon dioxide emissions from 2019.

The study emphasizes that this stored carbon poses a significant risk of contributing to greenhouse gas emissions. Researchers suggest increasing product lifespans and recycling rates to limit the entry of fossil carbon into waste streams. Senior author Klaus Hubacek highlighted the growing stock of carbon in human-made materials, which now surpasses carbon in the natural world, urging a shift in focus from carbon flows to stocks.

Using 2011 data, the researchers estimated carbon inputs and outputs across economic sectors by calculating the average carbon content of products. For instance, plastics contain about 74% fossil carbon. Their analysis included durable plastics, bitumen used in roads, and fossil carbon-based feedstocks used as intermediates in industries. They found that 9% of fossil carbon in 2011 was stored in long-lasting products, equivalent to the European Union’s emissions that year (3.7 gigatonnes vs. 3.8 gigatonnes).

Buildings and infrastructure accounted for the highest share of stored carbon at 34%, followed by rubber and plastic products at 30%, bitumen at 24%, and machinery and equipment at 16%. Extrapolating the 2011 data, the researchers estimated an annual addition of 0.4 billion tonnes of fossil carbon to the techno-sphere, highlighting its growing potential to exacerbate greenhouse gas emissions.