The legal cannabis industry is in its infancy and CO2 is a relatively new topic, even for packaging and storage before it gets to the consumer, while mold growth and degradation of quality have been major concerns, especially for long term storage for personal cannabis.
Cannabinoid and turpene degradation will happen naturally and cannabis can eventually lose much of what it was purchased it for. Environmental factors such as light, temperature, moisture and oxygen, can speed up the process and maintaining a controlled environment with low oxygen, low light and stable temperatures, will combat the natural processes that degrade the herb, allowing it to stay fresh and viable for longer.
CO2 has been a proven safe product to aid in the storage of perishables and works with cannabis storage by replacing the oxygen to stop mold growth or oxidization of any volitile turpenes and cannabinoids preventing the degredation of the product.
https://brinstrument.com/blog/cannabis-distillation/cbn-an-oxygen-degradation-product-and-how-to-avoid-it/
CBN is an oxidized form of THC that is known for its sedative effects. CBN naturally occurs in cannabis.
Concentrations of 4% or more in oil concentrate, might indicate poorly stored or aged cannabis with prolonged exposure to oxygen.
https://www.unodc.org/unodc/en/data-and-analysis/bulletin/bulletin_1997-01-01_1_page008.html
The percentage loss of THC was proportional to the storage time. On average, the concentration of THC in the plant material decreased by 16.6% ±7.4 of its original value after one year….
https://weedmaps.com/learn/dictionary/cannabinol-cbn
The degradation of THC to CBN can be accelerated by exposing dried plant matter to oxygen and heat.
https://www.leafly.ca/news/cannabis-101/factors-influencing-cannabis-degradation
Volatile monoterpenes begin to polymerize at surprisingly low temperatures, meaning that the flavor and aromatic profile of your cannabis flowers could change as well.
Temperature and humidity are both highly influential to cannabis degradation, high exposure to UV light and oxygen can perhaps cause the highest rates of degradation in the shortest time frame.