A quick way freelancers can guestimate their carbon emissions

1. Multiply the number of hours you typically work in a day by 0.33378. Eg if you work 8 hours a day, the number is 8 x 0.33378 = 2.67024 kgCO2e/day. Now you know your emissions per day. That 0.33378 kgCO2e per hour worked is an emissions factor for “Homeworking (office equipment + heating)” from UK Gov’s GHG reporting conversion factors 2024 (Homeworking tab C24), which uses the EcoAct 2020 Homeworking emissions whitepaper as its methodology. And “kgCO2e” means kilogrammes of several different greenhouse gas emissions expressed as the equivalent in carbon dioxide.
2. Multiply that number by the number of days work you did in a month or year. Eg, if you worked 200 days in a year, 2.67024 kgCO2e/day x 200 days = 534.048 kgCO2e.
3. Optionally, disclose that number to your customers. Under the GHG Protocol, you’re probably not required to disclose your emissions to your customers, and your customer might not be required to disclose the emissions in their scope 3 emissions reporting. But I think it is useful to model the world we want to see, so I tell my customers.

The limitation: it’s quick but not particularly accurate, because you might have a lot of other emissions that this method doesn’t count.

But it is more accurate than not counting at all. How you’d make it more accurate:

• Add days working at customer sites, which your customer might account for with a different emissions factor.
• Add business related travel: kilometres and whether it was plane, mass transit or car.
• And add work-related expenses: value and accounting code (which is probably a matter of discussion with your customer). At this point you’d have something more accurate for your customers, but it still wouldn’t count everything in a freelancer’s emissions so it’s probably a floor on the true number.
• the next leap would be to properly measure your emissions activity by activity, which is a bigger project. Tbh when I measured mine I got a number that is 16 times bigger than I did using the quick method above. 16x! I think this is because I’m measuring more things, am generally maximalist in my measurement, and I choose to include pension and financial services in my numbers on the basis that the emissions are real even though the GHG Protocol requires only financial services firms to disclose them. (This difference raises a question: what numbers are fair to disclose to customers? Perhaps I should include both numbers and let the customer choose which they include in their own emissions reporting.)