Your base year is a key determinant when setting reduction targets since your total emissions in that year (i.e. your base emissions) are ultimately used to inform the scale of emissions reductions required over the following years and highlight emissions hotspots to focus attention towards:

The base year is a baseline from which emissions reductions are determined and the initial point of reference against which future progress is measured. This historical context is vital for evaluating the effectiveness of emission reduction efforts.

The base year assessment aids in determining the primary sources of emissions within an organisation's operations. This information is invaluable for prioritising reduction efforts, enabling your organisation to allocate resources towards areas contributing the most to its carbon footprint.

To establish meaningful and attainable emissions reduction targets, your organisation must first understand its historical emissions. Determining what constitutes a realistic and ambitious reduction goal is only possible with a clear base. Setting targets that are either too aggressive or too conservative can impede progress.

The base year assessment informs strategic planning by providing insights into your organisation's carbon footprint and assists decision-makers in creating informed decarbonisation action plans based on actual emission hotspots.

The base year provides a benchmark against which to measure progress. It enables your organisation to monitor whether you are progressing toward meeting your emission reduction objectives. Routine assessments help detect deviations from the intended course and prompt corrective actions.

In general, the year that you’ve calculated your first comprehensive and thorough Corporate Carbon Footprint is a good candidate to become your base year.

This means that an ideal base should:

Base years are often set from January to December of the year, however you can also use the months or your financial year.

Since national average values are not specific to your organisation's business activity, they only represent an estimate of emissions based on national trends, and are therefore less accurate. Similarly, some calculation methods yield high levels of accuracy than others.

One key reason to use the most accurate year is that emissions values determined by national averages are not conducive to determining a decarbonisation pathway specific to your business. This is because the emission reduction potential of decarbonisation actions will be based on data which is not specific to the reality of your organisation. For example, it is difficult to know whether implementing a cycle to work scheme will reduce emissions if you don't know how many people already cycle to work.

Similarly, in an ideal scenario, your data quality will improve over time as your data collection process matures, which will impact your total emissions values. For instance, if you set your base year using national averages and gain access to primary activity data for following years, it could be that emissions values are indeed higher for some emission categories than estimated initially through the use of national averages. This, in turn, would mean your targets are set based on underestimations, leading to additional challenges in achieving them.

Essentially, the more solid the foundations your base year emissions are set on, the more robust the targets you can set.