I have found myself in a rather unexpected place over the past few days. For more than two decades, I have been incessantly proclaiming that we produce far too much carbon dioxide (CO₂) with the associated risks of global warming. But while ever more is being pumped into the atmosphere, Europe and Mexico are also running out of usable CO₂ – as several plants that produce CO₂ have closed down for maintenance.
In total, the world consumes about 80m tonnes of CO₂ per year. Annual CO₂ emissions are currently around 32 billion tonnes, but we have experienced the worst CO₂ supply shortage in decades in the UK. Most of the UK’s CO₂ demand is met as a byproduct from the fertiliser industry that generally closes operations during the summer months. We do produce CO₂ from many other sources, but despite the development of CO₂ capture technologies, these are not deployed at the commercial pace needed to actually be able to use it.
In the UK, the situation has been exacerbated by the current heat wave and pubs running out of beer – precisely in the middle of the football world cup. But is CO₂ really that critical to how society functions? The short answer is yes, and here are ten applications that are threatened by a shortage of CO₂.
There’s been a bit of a panic about running out of beer in the middle of summer. But there are many other applications of CO₂ in the drinks industry, such as carbonated soft drinks. But if you are more of a wine drinker or even a connoisseur, you are not home free. CO₂ addition is essential for wine making and achieving the perfect fermentation.
2. Food of all kinds
CO₂ also has many applications in the food industry, too, from its use in abattoirs and stunning farm animals before slaughter to the preservation of fresh meat in vacuum-sealed packaging. And vegetarians are just as vulnerable, especially crumpet lovers. CO₂ is used widely as refrigerant in food retail applications, including many fruits and vegetables.
CO2 laser. Etan J. Tal/wikipedia, CC BY-SA
CO₂ lasers are one of the most useful and efficient lasers, producing a beam of infrared light. This is not only relevant for Star Wars fans, CO₂ lasers have a wide range of applications in industry for cutting, welding, engraving and even 3D printing. What’s more, medical CO₂ lasers are used in many soft tissue surgical procedures, from removing vocal cysts to face lifts.
4. Fire extinguishers
CO₂ is a non-combustible that can be pressurised – hence its ubiquitous use in fire extinguishers. But pressurised CO₂ gas is also used in airguns and self-inflating life jackets. CO₂ canisters are also sold as a cyclist’s best friend for repairing punctures.
5. Decaf coffee
At certain temperature and pressure (31°C and 73 atmospheres) CO₂ becomes a supercritical fluid. That does not mean it is critically dangerous, but rather that it has very unusual and extremely useful properties. For example, it has the density of a liquid, but behaves like a gas. Supercritical CO₂ is used as an environmentally friendly solvent for dry cleaning, decaffeinating coffee and in the production of herbal distillates and essential oils, among other things.
Dry ice is simply solid CO₂. This can be used in large, well-known applications, such as blast cleaning, food refrigeration and flash freezing, to small scale uses, such as fog machines and wart removal. Dry ice can also be used to preserve the human body until a funeral and is more environmentally friendly than embalming chemicals.
The largest single industrial use of CO₂ is for something called “enhanced oil recovery”. Every year, about 50m tonnes of CO₂ are injected into oil reservoirs to push out around 20% of the original oil in place. Most of the CO₂ used for this application comes from natural CO₂ wells.
We know that plants are big consumers of CO₂. Through photosynthesis, plants convert CO₂ and water into hydrocarbons. But did you know that gardeners artificially increase the levels of CO₂ in their greenhouses to promote plant growth?
Will we run out of aspirin? Zadorozhnyi Viktor/Shutterstock
9. Pain killers
CO₂ has many pharmaceutical and medical applications, such as for the production of analgesic and anti-inflammatory drugs. For example, CO₂ is used in the production of salycilic acidthat is the precursor to aspirin. It is also used for the stimulation of breathing when added to oxygen.
10. Aviation fuels
CO₂ is used extensively in research labs, as compressed gas, supercritical fluid or dry ice. In the lab where I work, we may not be using food grade CO₂, but we are nevertheless affected by the shortage. Our supplier recently communicated to us that they are “no longer accepting routine orders”. And this has consequences. For instance, in one of our research projects we use CO₂ together with waste biomass to produce aviation fuels.
So, I have come to realise that after all these years talking about CO₂ associated with global warming and climate change, I need to change my research narrative. Let me try this: our research is committed to ensuring that every day you have the CO₂ required for you to continue enjoying your lifestyle, from your preferred food and drink to riding your bike or even using a life jacket.
Mercedes Maroto-Valer receives funding from Engineering and Physical Sciences Research Council (EPSRC-UKRI), European Research Council (ERC) and EU-H2020.
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