CO2 emissions from energy ≡
Population × (gross domestic product (GDP) per head of population) × (energy use / GDP) × (CO2 emissions / energy use)
GDP per person (or "per capita") is used as a measure of economic affluence, and changes in technology are described by the other two terms: (energy use / GDP) and (energy-related CO2 emissions / energy use). These two terms are often referred to as "energy intensity of GDP" and "carbon intensity of energy," respectively.[43] Note that the abbreviated term "carbon intensity" may also refer to the carbon intensity of GDP, i.e., (energy-related CO2 emissions / energy use).[43]
Reductions in the energy intensity of GDP and/or carbon intensity of energy will tend to reduce energy-related CO2 emissions.[42]:177 Increases in population and/or GDP per capita will tend to increase energy-related CO2 emissions. If, however, energy intensity of GDP or carbon intensity of energy were reduced to zero (i.e., complete decarbonization of the energy system), increases in population or GDP per capita would not lead to an increase in energy-related CO2 emissions.