Carbon Footprint
The total amount of greenhouse gases (primarily CO2) generated by human actions, measured in tonnes of CO2 equivalent per year. It includes direct emissions from driving and heating, and indirect emissions from the production of goods and services you consume.
The concept of a carbon footprint was popularized in the early 2000s, though the underlying science dates back to the 1990s. The global average carbon footprint is about 4.8 tonnes of CO2 per person per year, but this varies wildly by country. Americans average about 16 tonnes, Europeans about 6-8 tonnes, and people in many developing nations under 2 tonnes.
How It's Calculated
Carbon footprints are calculated using Life Cycle Assessment (LCA) methodology, which traces emissions across the entire supply chain of a product or activity. For individuals, the main categories are transportation (about 28% for the average American), home energy (about 25%), food (about 14%), and goods and services (about 33%).
Scope 1, 2, and 3
For businesses, emissions are categorized into three scopes. Scope 1 covers direct emissions (company vehicles, on-site fuel burning). Scope 2 covers indirect emissions from purchased electricity. Scope 3 covers everything else in the value chain, from employee commuting to product end-of-life. Scope 3 typically represents 70-90% of a company's total footprint.
Reducing Your Footprint
The most effective individual actions to reduce your carbon footprint are: living car-free (saves 2.4 tonnes/year), taking one fewer long-haul flight per year (saves 1.6 tonnes), switching to a plant-rich diet (saves 0.8 tonnes), and switching to green energy (saves 1.5 tonnes). Taking the Eco Score quiz helps identify which areas offer the most improvement potential for your specific lifestyle.
Related Terms
Carbon Neutral
Achieving net-zero carbon dioxide emissions by balancing the amount of CO2 released into the atmosphere with an equivalent amount removed or offset. This can be achieved through a combination of emission reduction and carbon offsetting.
Ecological Footprint
A measure of human demand on nature, expressed as the amount of biologically productive land and water area needed to produce the resources consumed and absorb the waste generated. Measured in global hectares (gha).
Net Zero
The state where the total amount of greenhouse gases emitted is balanced by the total amount removed from the atmosphere. Unlike carbon neutral, net zero typically requires deep emission reductions (90%+) before offsets are used for remaining emissions.