I = PAT that human population may stabilize at around 11.2 billion in 2100, the I=PAT equation will continue to be relevant for the increasing human impact on the environment in the short to mid-term future. Increased population increases humans' environmental impact in many ways, which include but are not limited to: The variable A, in the I=PAT equation stands for affluence. It represents the average consumption of each person in the population. As the consumption of each person increases, the total environmental impact increases as well. A common proxy for measuring consumption is through GDP per capita. While GDP per capita measures
Disposable household and per capita income Disposable household and per capita income Household income is a measure of the combined incomes of all people sharing a particular household or place of residence. It includes every form of income, e.g., salaries and wages, retirement income, near cash government transfers like food stamps, and investment gains. Average household incomes need not map directly to measures of an individual's earnings such as per capita income as numbers of people sharing households and numbers of income earners per household can vary significantly between regions and over time. Average household income can be used as an indicator for the monetary well-being