The annual measurement usually refers to the past 12 months of company carbon emissions but it is also possible to focus on a calendar year.   Care must be taken to find a 'representative' year if companies are going back to Calendar year format to ensure that it reflects current emissions.   2020 and 2021 will be seen by many as exceptional in terms of either significantly reduced or enhanced activity beyond the norm.   For this reason it makes good sense to begin the Carbon footprint measurement retrospectively from a 12 month historical period of normal activity.   It is important that the report is validated and accredited by a third party if possible.  Many of the leading Carbon footprint calculators change metrics and are updated regularly as knowledge continues to expand in this area.  The measurement of both upstream and downstream emissions is not a simple task and must be included in all footprint measurements.
 

The validated CCF report will be used to inform concrete discussions around any reduction strategy.   The granular detail of the report will allow stakeholders to hone in on specific areas that need attention as well as pointing out areas where possible immediate reductions can take place.  Similar to financial accounts the breakdown will inform discussion and debate around each of the specific areas under consideration.  It is often the case that  Carbon Footprint measurement will often surprise in terms of what might have been assumed in advance.
 
Finally the report will be used to inform and direct 'realistic' long term organisational sustainability Goals such as longer term reduction targets, Carbon Neutral discussion or Net Zero ambitions.         
 

The initial report becomes a benchmark against which the sustainability program can now be measured in tangible terms.   The critical emission contributors within the organisation have been identified clearly and it becomes good practice to regularly monitor each and every contributor to note the upward or downward movement.  Similar to standards in financial accounting whereby each line in a profit and loss or Balance sheet can be compared to the previous years, a similar structure should be adopted for Carbon Footprint measurement.  Overall reduction targets should be set but there might be increases in certain areas compensated by larger reductions in other areas.  Reduction targets might not be possible in the very short term and longer-term structural change might be required.  Again the carbon footprint measurement report can provide the basis for longer term structural decision making if necessary as well as the short term program.

Yes - the most difficult task is the initial exercise of gathering the contributing factors.  Once this is done for the first time, it becomes easier to know where to locate the data for comparison reasons. Rather than undertaking the exercise once a year it is again best practice in the second and subsequent years to monitor and measure on a quarterly basis to be included in overall company KPI reporting.  There are several carbon counting software packages on the market (and many more emerging) that can help organisations to regularly monitor and report on the carbon accounting on an ongoing basis. Ideally the responsibility would be assigned internally as a key job function with the help of external validation.