Here we compare the values from both methods of calculating our carbon footprint. We work through the pros and cons and arrive at a decision about which method to use. We are still not absolutely sure which is the correct figure and, if we are not sure, it does not really help the many other small businesses just starting out on this journey. It may be that the emission factors from the government underestimate the scope 3 emissions which may be a reason for under-reporting of this aspect of greenhouse gas emissions.