<Dl> <Dd> I = P × A × T </Dd> </Dl> <Dd> I = P × A × T </Dd> <P> The expression equates human impact on the environment to the product of three factors: Population, Affluence, and Technology . It is similar in form to the Kaya identity which applies specifically to emissions of the greenhouse gas carbon dioxide . </P> <P> The validity of expressing environmental impact as a simple product of independent factors, and the factors that should be included and their comparative importance, have been the subject of debate among environmentalists . In particular, some have drawn attention to potential inter-relationships among the three factors; and others have wished to stress other factors not included in the formula, such as political and social structures, and the scope for beneficial, as well as harmful, environmental actions . </P>

The i = pat formula says that our environmental impacts (i) are the product of