Rethinking carbon in green chemistry
Dr Daniel Stewart, co-founder and CEO of Viridi, looks at the use of CO 2 as a feedstock
Green chemistry has long focused on reducing the environmental footprint of chemical manufacturing. Over the past two decades, researchers and industry practitioners have made substantial progress in improving catalytic efficiency, reducing solvent use and developing alternative feedstocks. These advances have helped lower emissions, reduce waste streams and improve the sustainability of chemical processes across multiple sectors.
Yet an important structural challenge remains. Modern chemical manufacturing still relies heavily on fossil carbon as the starting point for many materials and molecules. More than 90 % of organic chemicals are still derived from fossil feedstocks, according to a 2025 report by the Renewable Carbon Initiative. Even when production processes become more energy-efficient or are powered by renewable electricity, the carbon embedded in products often originates from petrochemical sources.
This reality raises a fundamental question for the future of sustainable chemistry: where will the carbon used to build chemicals come from in a decarbonised economy? One possible answer lies in a source that the industry has historically treated as waste: carbon dioxide.
The challenge
The chemical industry accounts for about 5-6 % of global greenhouse gas emissions, as per the IEA. This impact arises not only from the energy required to run chemical plants but also from the nature of the materials themselves. Carbon is a central element in a vast range of chemical products, from polymers and coatings to surfactants and pharmaceutical intermediates.
Unlike sectors such as power generation, where emissions are largely linked to energy production, the chemical industry faces a dual challenge. It must reduce both the energy-intensity of manufacturing processes and the fossil origin of the carbon atoms that form the backbone of many products.
Even if chemical facilities were powered entirely by renewable electricity, a large proportion of products would still originate from fossil-derived feedstocks. Petrochemical intermediates remain the dominant source of carbon in many chemical value chains. Addressing emissions, therefore, requires more than energy transition alone; it requires
rethinking the origin of carbon used in chemical manufacturing.
Progress already made
Green chemistry has already delivered meaningful advances in improving sustainability within the sector. Biobased feedstocks have gained increasing attention, particularly in the production of polymers, solvents and speciality ingredients derived from plant-based materials. These approaches aim to replace fossil carbon with renewable carbon sources obtained from biomass.
At the same time, advances in catalysis and reaction engineering have significantly improved process efficiency. Catalytic systems have become more selective, enabling reactions to proceed under milder conditions while reducing energy consumption and by-product formation. Process intensification strategies have also improved reactor design, increasing productivity while reducing waste and resource use.
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