CI is a standardized measure of the carbon emissions associated with a product or activity

Ci is an important element of many emissions regulation policies such as LCFS, where it is used to set limits and measure compliance.

CI typically measures attempts to measure the full life-cycle emissions for sourcing and using a fuel, including emissions from feedstock sourcing (eg oil production), fuel production and distribution (eg refining), and final end use (ie buring the fuel in a vehicle).

The units for CI are typically grams of CO2 equivalent emissions per megajoule of energy provided (gCO2e/MJ).