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
Population ecology in a population can be described as: where "N" is the total number of individuals in the population, "B" is the raw number of births, "D" is the raw number of deaths, "b" and "d" are the per capita rates of birth and death respectively, and "r" is the per capita average number of surviving offspring each individual has. This formula can be read as the rate of change in the population ("dN/dT") is equal to births minus deaths (B - D). Using these techniques, Malthus' population principle of growth was later transformed into a mathematical model known as the