Traditional agricultural practices contribute to about 20% of global annual emission of CO2 [1]. The carbon footprint refers to how much greenhouse gas is emitted from an activity of an enterprise. The carbon footprint for a farm is the ratio of total GHG emissions to total outputs of the farm enterprise. Carbon emission may be calculated from direct or indirect emissions [2]. Direct emissions are as a result of activities directly linked with the farm like irrigation, harvesting, tillage which all require the use of diesel machinery responsible for emission of CO2 into the atmosphere. The indirect sources include purchased electricity from the grid and transportation of crop produce to customer location. Other greenhouse gases are Nitrous oxide and methane.

In terms of carbon footprint, comparisons were made between the traditional and vertical farms (Liberty Farms in Dundee and CropBox in America) to verify the gap in the emission of CO2 between the two types of farming techniques and to justify the advantage of vertical farming. To make this comparison, the emissions from both the direct and indirect source are quantified, tabulated and multiplied by the appropriate carbon factor (emission coefficient provided by the UK Government) [3]