How to measure your GHG emissions baseline

How to measure your GHG emissions baseline

Learn the 3 steps to calculate your company’s GHG emissions baseline so you can set targets and report your progress towards your net zero objective.

Measuring your GHGs can seem like an insurmountable mission, but by breaking it up into manageable tasks and employing helpful tools and services you’ll be putting yourself in the best possible position to begin recording your emissions reduction journey. To get you started, we’ll walk you through the first stage of GHG emissions measurement: calculating your initial GHG emissions baseline.


What is a GHG emissions baseline? 

A baseline provides a snapshot of an organization's GHG emissions at a particular moment in time and acts as a reference point for measuring changes in the amount of GHGs you emit from your baseline year and onward. Ultimately, a baseline serves as the primary starting point for emissions sourcing, calculation, target-setting, tracking, progress measurement, and reporting.


Steps to calculating a baseline?

Step 1

The first step to calculating your baseline is taking stock of your emissions sources, otherwise known as your “activity data”. For this, you’ll want to collect an inventory of your organization’s scope emissions, which are separated into your direct, scope 1 emissions (emissions from sources owned or controlled by a company, such as company-owned vehicles) and your indirect scope 2s (emissions from purchased electricity, heating, and cooling) and scope 3s (emissions produced as a consequence of a company’s activities throughout their entire value chain, including suppliers and customers). An example of activity data might be kWh of electricity used or kilometers travelled by company car.

Your activity data can be found in the likes of energy bills, car mileage, and flights, which are usually contained in your company’s financial management system. In a larger organization, some of this information may be readily available from departments (generally the finance department) within your organization. In this case, you’d identify the employees who have access to your company’s energy bills, leased car mileage, and grey fleet (personal vehicles driven for business purposes) expense reports or mileage used. Other information, such as flights, rail journeys, and hotel stays can be found on third-party websites, such as the International Civil Aviation Organization, RailMiles, Calculator Carbon Footprint, or HotelFootprints.

If you are an organization that produces goods and services, you’ll also need to look into the direct emissions caused by your manufacturing process (upstream emissions), as well as the indirect emissions resulting from the suppliers who provide you with raw materials and the customers who use, and perhaps eventually dispose of, your products (downstream emissions). To find out more about your upstream emissions, you can consult your procurement staff, who should know everything that goes on in your supply chain.


See the World Bank’s Energy Balance and GHG Inventory Spreadsheet outline of the data you might include in your GHG inventory. 


Step 2

Next, you’ll look up your activity data’s emissions conversion factor, or “emissions factor” in an emissions factor database, such as the IEA emission factors database or, if you’re in the UK, the GHG reporting conversions factors provided by the UK government. It’s important to note here that emissions factor databases are region and time-specific and updated regularly, so for accurate results, you must choose the emissions factor data that corresponds to your region of operation and your baseline year.


An emissions factor is measured in tons or kilograms of carbon dioxide equivalent (tCO2e or kg CO2e), which takes into account all GHGs and not just CO2.


Step 3

Lastly, you can calculate your GHG emissions based on the relevant emissions factor using the following calculation:

Activity data x Emissions factor = GHG emission 

For example, say you live in the UK, your baseline year is 2022, and your activity is electricity usage, for which you used 1000 kWh. By looking up the emissions factor for electricity for that year, you’ll discover that it’s 0.19338 kgCO2e per unit (i.e. kWh or m^3). 

Now that you have your activity data (in this case, your electricity used) and your emissions factor (measured in kilograms of carbon dioxide equivalent, or kgCO2e), you can multiply them to find out how much carbon dioxide equivalent (which takes into account all GHGs and not just CO2) you’ve emitted due to your electricity usage. 

So now your equation would be: 

1000 kWh x 0.19338 kgCO2e/kWh = 193.38 kgCO2e 

Once you’ve calculated all your emissions in each scope, you can add them up to discover your company’s total emissions. 


What next?

After you’ve calculated your emissions for your baseline year, you’ll be in a good position to set a science-based target as well as interim targets, which should ideally be verified before you report your emissions. This process of calculating, verifying, and reporting is best performed annually to measure your emissions reduction progress, comply with environmental regulations, and boost stakeholder confidence.

For all the resources you need to calculate your baseline and measure your emissions, check out our emissions calculation cheat sheet.