I=PxAxT (commonly pronounced “eye-pat”) is a formula alleged to describe the factors that cause environmental degradation. In this formula, I stands for impact; P for Population; A for Affluence (or amount consumed); T for Technology. It alleges that the three factors compound.
NG (Mar 2011) recently gave credence to the formula by putting a full page illustration of how “I” has exploded over the last 111 years. Since 1900, world GDP (a measure of A) and the number of patent applications (a measure of T) have grown even faster than the population. Human impact (I), which had been growing steadily since the industrial revolution, started to explode exponentially after WWII, a phase some scientists now call the “great acceleration.”
But, as it turns out, IPAT isn’t particularly useful, and NG was wrong to give it the publicity it did. It is far too simplistic to account for the complex array of interactions that take place between the variables. Also, the formula categorizes all “T” as something negative, something harmful to the planet. This is obviously not the case.
One modificaion suggests that I=(PxAxT1)/T2. This formula distingishes between technology for mass production (T1) and technology that improves efficiency and/or reduces pollution (T2). According to this modification, the turning point in the “I” curve will come when PAT1<T2.
While the latter is still a gross oversimiplication, it attempts to show slightly more defensible relationships.