Does the CO₂ bioeconomy create value from carbon dioxide? Scientists from the University of Sheffield explain various aspects of this issue; we have summarised them in this material.

Humanity's “relationship” with carbon dioxide

Carbon dioxide is often portrayed as the “main villain” of climate change. In less than 200 years, the amount of CO₂ in the atmosphere has increased by 50% (data source: National Oceanic and Atmospheric Administration), which is a vivid reminder of the role carbon dioxide plays in global warming.

Scientists have linked the increase in carbon dioxide levels over the last 66 million years to the greenhouse effect (source: Annual Review of Earth and Planetary Sciences). In addition to scientific reports, we have also experienced heatwaves ourselves, which made the summer heat unbearable in many places; we have witnessed temperature records in the United Kingdom, where on 19 July 2022, the highest air temperature to date was recorded – +40.3 °C. Can we blame carbon dioxide for climate change?

Greenhouse gases “trap” the Earth's heat radiated by the sun in the atmosphere, preventing it from escaping into space. Carbon dioxide is just one of the greenhouse gases listed in the Kyoto Protocol (CO₂, CH₄, N₂O, and fluorine-containing gases). Although its “warming potential” is lower than, for example, methane, it remains in our atmosphere for up to 1,000 years and accounts for roughly one-third of total global warming.

Our reliance on fossil fuels is a significant cause of current climate problems. Fossil fuels have driven the industrial revolution, also stimulating social development. Coal, oil, and natural gas remain the primary resources in the global energy system and significantly contribute to carbon dioxide emissions.

Emissions are inextricably linked to economic growth; it has been concluded that wealthier developed nations have historically emitted more carbon dioxide, and it is time for them to begin “decoupling” their economic growth from emissions (making economic growth independent of fossil resources). For example, the UK's GDP has increased over the last 30 years, while total emissions have decreased (source: Our World in Data).

Carbon dioxide has overshadowed its other essential role in the life of our planet. CO₂ and other greenhouse gases, by trapping solar heat, maintain a warm climate on Earth that is suitable for various life forms, including humans. Carbon is the “backbone of life,” which also makes up about 18% of human body mass. In the carbon cycle, it is moved between various reservoirs. For example, plants use carbon dioxide to “produce” food that is consumed by humans and animals, thus transferring carbon to us. Carbon dioxide is not only important in nature, but it is also used commercially in many ways, for example, in the production of soft drinks, beer, and wine, as an inert coating for food storage, and as a cooling agent for flash freezing.

CO₂ is a raw material for the production of methanol and urea. Injected into oil wells, it can improve oil extraction. Less known are other applications, such as in the decaffeination process for coffee and in surgical procedures, for instance, laparoscopy. (Laparoscopic technique eliminates the need for large incisions. Instead, the surgeon can view organs from inside the body using a laparoscope – a thin instrument resembling a telescope. After carbon dioxide is introduced into the abdominal cavity, the laparoscope is inserted into the patient's body through a small tube (trocar), through which internal tissue puncture is performed.).

Innovations in the fight against climate change

Research and innovation are crucial in the fight against climate change. Replacing fossil fuels with other energy sources is often the key change needed to reduce emissions. The main alternatives are solar, nuclear, wind energy, and biomass. Alternative energy sources are “cleaner” compared to fossil fuels; their emissions are either very low or non-existent. Solar, wind, and biomass energy are also renewable energy, which means their supplies can be “limitless” compared to the 57-year reserve of oil (source: Our World in Data).

To prevent global temperatures from rising above 1.5 °C, the UK's target is to reduce emissions by 78% by 2035 compared to 1990 levels. Many national governments have set similar goals. It is clear that these can only be achieved if a “clean” energy strategy is strengthened and implemented in daily life, with a serious, well-designed, and balanced plan for “removing” carbon dioxide from the Earth's atmosphere.

Carbon dioxide is used by plants. The aforementioned task is achievable by restoring forests, sequestering carbon in the soil and ocean directly from the air, and mineralising carbon into solid carbonates. Most of the technologies planned to achieve the above are in the early stages of development or implementation. The main obstacle remains their very high cost, which forces a critical assessment of their economic sustainability.

Innovations that convert carbon dioxide into products are attracting the attention of governments and investors. These technologies are “creating a CO₂ economy,” which turns carbon dioxide into a financially profitable investment. Carbon dioxide “removal” is becoming economically viable. The main product categories are fuel, chemicals, and construction materials.

Carbon dioxide assets

The main advantage of using CO₂ as a raw material in production is its availability and “abundance.” Every year on Earth, about 33 billion tonnes of anthropogenic CO₂ are “produced” (this corresponds to 9 billion tonnes of carbon), compared to about 4.5 billion tonnes of crude oil and natural gas. Plants and algae are biological “agents” that “consume” CO₂. Less well-known are bacteria that feed on carbon dioxide. These are living organisms, also known as autotrophic bacteria, which capture CO₂ and use it to grow and synthesise complex organic products. The ability of bacteria to double their mass within a few hours gives them certain advantages compared to plants or algae.

At the University of Sheffield, the natural capabilities of autotrophic bacteria are being utilised and their performance improved using synthetic biology, enhancing the utilisation of carbon dioxide and expanding the range of products derived from it.

One such project is researching the conversion of atmospheric carbon dioxide into sustainable, biodegradable polymers that can replace fossil plastics. This creates new sustainable opportunities in several areas: carbon dioxide “removal” (capture), moving away from the use of fossil fuels, as well as the ability to use biodegradable polymer products in daily life, successfully addressing the problem of plastic pollution.

The scientists' vision is to use autotrophic bacteria as miniature cell factories and carbon dioxide as a raw material to produce chemicals, biopolymers, and proteins for wider consumption.

Given the scale of climate problems and the need for urgent action, various technologies must definitely be used, and this must be done comprehensively, which is why it is crucial to continue investing in the development of CO₂ “removal technologies.” Research and development, funding, the commitment of governments and companies, as well as clear information are essential factors for society so that early-stage ideas become real future solutions.