Carbon dioxide (CO2) is one of the major greenhouse gases contributing to global warming and climate change. As we burn more fossil fuels like coal, natural gas and oil to power our modern societies, the levels of CO2 in our atmosphere have risen dramatically in recent decades. The National Oceanic and Atmospheric Administration (NOAA) reports that current CO2 levels are over 410 parts per million (ppm), which is the highest it has been in at least 800,000 years. If we do not find ways to reduce our CO2 emissions and draw down carbon from the atmosphere, scientists warn that the impacts of climate change like rising sea levels, stronger storms, more extreme weather events and wildfires could be catastrophic by the end of this century.

Carbon Dioxide Utilization into Useful Products and Fuels

With CO2 levels rising so rapidly, researchers are searching for new solutions to utilize this greenhouse gas and convert it into value-added products and alternative fuels. One promising approach is carbon dioxide utilization (CDU), which involves technologies and processes that capture CO2 emissions and incorporate the carbon into commercially valuable materials or products. Some key examples of CDU include:

- Producing synthetic fuels like gasoline, diesel or jet fuel through CO2 hydrogenation or the Fischer-Tropsch process. This involves using renewable hydrogen to convert CO2 into carbon-based synthetic fuels that can directly replace traditional fossil fuels.

- Making building materials like concrete, glass and ceramics. CO2 can react with calcium and magnesium silicates during production to form stable carbonates that become part of the final material, permanently storing the carbon.

- Growing algae for renewable biofuels or nutraceuticals. Certain algae species like chlorella and spirulina thrive on CO2 and use photosynthesis to rapidly multiply their biomass, which can then be processed into biodiesel, jet fuel or nutritional supplements.

- Synthesizing polymers and plastics. Advanced chemical recycling technologies can break down plastic waste into synthetic gas, from which new virgin-quality plastics can be produced using captured CO2 as a carbon feedstock.

- Producing carbonated beverages. Soda and sparkling water manufacturers regularly capture and utilize large amounts of CO2 that would otherwise be emitted from fossil fuels or industrial processes.

Reducing CO2 Emissions through Substitution and Storage

For any Carbon Dioxide Utilization technology to meaningfully impact global warming, the CO2 being utilized must ultimately lead to a net reduction in atmospheric carbon compared to just venting the emissions. There are two main ways this substitution effect and storage of carbon happens:

1. Fossil fuel substitution - Using synthetic fuels produced from CO2 and renewable energy allows us to partially or fully replace conventional oil, diesel and gasoline. As long as renewable energy sources like solar, wind or hydropower are used for fuel synthesis, it results in a net uptake of CO2 from the air compared to continuously burning fossil carbon reservoirs.

2. Permanent carbon storage - Many CDU approaches like mineralization, plastics production or growing biomass and burying it permanently lock carbon into solid products, sinks or reservoirs. This prevents the sequestered CO2 from re-entering the atmosphere for centuries or millennia, achieving deliberate long-term storage that offsets continued emissions from other economic sectors. With proper management and accounting, CDU can be a form of carbon capture and storage (CCS) technology.

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