the i = pat formula says that our environmental impacts (i) are the product of
I = PAT 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.
Greenhouse gas Human activities since the beginning of the Industrial Revolution (taken as the year 1750) have produced a 40% increase in the atmospheric concentration of carbon dioxide, from 280 ppm in 1750 to 406 ppm in early 2017.[6] This increase has occurred despite the uptake of a large portion of the emissions by various natural "sinks" involved in the carbon cycle.[7][8] Anthropogenic carbon dioxide (CO2) emissions (i.e., emissions produced by human activities) come from combustion of fossil fuels, principally coal, oil, and natural gas, along with deforestation, soil erosion and animal agriculture.[9]