We quantify anything generating greenhouse gas emissions (fuel, electricity, food, waste…) at each step of our trips. As they generate different types of emissions for their production or usage (carbon dioxide, methane…), we use a common unit that reflects their relative impact on climate change.
This unit is called “carbon dioxide equivalent” (CO2e), and using it makes it easy for us to figure out what aspects of our trips are contributing the most to climate change. This metric also tells us how many carbon certificates we need to purchase to offset our emissions.
To convert a meal, km traveled, or nights in hotels into an actual amount of CO2e, we use UK’s Defra conversion factors, a reference used internationally and across industries.