Scope 1

Direct emissions from sources a company owns or controls — its own combustion, its own vehicles, its own process emissions.

Scope 1 is what comes out of your own stacks and tailpipes: fuel burned on site, refrigerant leaks, process emissions from chemical reactions such as calcination.

It is normally the best-measured part of an inventory, because the data is yours: fuel purchases, meter readings, maintenance records.

It is also normally the smallest. For most manufacturers Scope 1 is a minority of the total, which is why an inventory that stops here says little about a company’s actual exposure.

Scope 2 Indirect emissions from the electricity, heat and steam a company buys.
Scope 3 All other indirect emissions across the value chain — purchased goods, transport, use of sold products, end of life.
GHG Protocol The most widely used standard for corporate greenhouse gas accounting; the origin of Scope 1, 2 and 3.