This reliance on byproduct capture creates a highly volatile market. Because CO2 is a secondary product, its availability is entirely dependent on the economic health and seasonal operation of the primary industries. For instance, ammonia plants often schedule maintenance shutdowns during the summer months when fertilizer demand is low. This predictable drop in production frequently leads to regional CO2 shortages precisely when the food and beverage industry needs it most for summer ice cream and beverage production. Furthermore, when global natural gas prices spike—as seen in Europe in the early 2020s—ammonia plants (which use natural gas as a feedstock) often shut down because they become unprofitable to operate. These closures inadvertently trigger severe CO2 shortages, leaving food processors scrambling and prices skyrocketing.

The medical field also relies on high-purity CO2. It is purchased by hospitals for insufflation—the act of bloating the body cavity with gas during laparoscopic or minimally invasive surgeries to give doctors room to operate. It is also mixed with oxygen to stimulate deep breathing in patients or used in cryotherapy to destroy abnormal tissue.

The primary sources of commercial CO2 are ammonia fertilizer plants, hydrogen production facilities, and ethanol refineries. In these facilities, CO2 is generated as a byproduct of chemical reactions. Industrial gas companies buy this raw gas, purify it to meet food or medical-grade standards, liquefy it under pressure, and distribute it to end-users.

Perhaps the most exciting frontier in purchasing CO2 is the synthesis of sustainable aviation fuels (e-fuels) and plastics. By combining captured carbon dioxide with green hydrogen, chemical companies can create synthetic hydrocarbons. When airlines or freight companies buy these synthetic fuels, they are participating in a closed-loop system where the carbon emitted during flight is the same carbon that was previously captured from the atmosphere or industrial chimneys.

Despite the fact that carbon dioxide is abundant in our atmosphere, the supply chain for purchasing industrial-grade CO2 is surprisingly fragile and complex. Unlike oxygen or nitrogen, which can be cost-effectively filtered and separated directly from ambient air using air separation units, capturing CO2 from the atmosphere on a commercial scale is still energetically and financially expensive. Consequently, the vast majority of carbon dioxide bought and sold today is captured as a byproduct of other industrial processes.

Agriculture is also evolving. Commercial greenhouse operators purchase CO2 to pump into their indoor facilities. Because plants consume carbon dioxide during photosynthesis, elevating CO2 levels in a controlled greenhouse environment can boost crop yields by up to 30 percent, accelerating plant growth and optimizing water use.