The carbon cycle has always been a crucial element of both ecosystem function and agri-food production. It involves dynamic interactions between sources (processes that release carbon into the atmosphere), sinks (processes that remove carbon from the atmosphere), and reservoirs such as the ocean, atmosphere, geosphere and the biosphere (including soil or forests) that can both store and release carbon (Table 1) (BS EN ISO 14064:1, 2019). Carbon flux refers to the amount of carbon exchanged between carbon stocks, for example, the flux from the atmosphere to the biosphere in which algae, fungi and plants sequester carbon dioxide (CO2) from the atmosphere, via photosynthesis to convert into organic molecules. These then travel through food chains before being released back into the atmosphere as CO2 via respiration.