What is the primary disadvantage of frozen carbon dioxide as a storage method?

The primary disadvantage of frozen carbon dioxide as a storage method is that it sublimates easily. This means that solid carbon dioxide, commonly known as dry ice, can transition directly from a solid to a gas without passing through a liquid state. This sublimation occurs at temperatures above -78.5 degrees Celsius (-109.3 degrees Fahrenheit) and can lead to loss of the material over time, making it less effective for long-term storage, as it can dissipate if not properly contained.

The other options present challenges that aren't inherent limitations of using frozen carbon dioxide specifically as a storage method, making them less relevant in the context of this question. For instance, high pressure is not necessarily required for storing frozen carbon dioxide, nor is it classified as extremely flammable or prone to rapid decomposition under normal storage conditions. Thus, the tendency of frozen carbon dioxide to sublimate easily poses the most significant drawback when considering its use as a storage medium.