Its simple mathematics (part 2): subject – algebra & IPAT

Have you ever heard of the formula:

I = P x A x T

From Ecoprofit Management: The formula’s evolution was the outcome of a debate between three guys, Barry Commoner, Paul Ehlich and John Holdren. “I” stands for environmental impact or environmental degradation, “P” is population, “A” is affluence, “T” stands for technology.

A basic tenant of algebra is that both sides of the equation have to be equal. Therefore, if you increase one side of the equation, the other side increases by the same amount.

According to the IPAT formula, if the world’s population increases by 655,000 in three days, then the other side of the equation i.e. environmental degradation, has to increase the same amount.

What we need is a common unit of measurement to apply to the formula. This is where the calculation principles of ecological footprinting come in handy. It uses global hectares (gha) as its unit of measurement. The total gha of the earth is calculated as all the productive land and sea available to provide the natural resources needed for all the things humans consume. Wealthier per capita countries like the USA (8 gha per person) and Australia (6.8 gha per person) have higher per capita footprints than countries like India (0.9 gha per person). This is because wealthier countries consume more things on a per capita basis. So for the USA, 8 gha represents the amount of productive land and sea needed per person to not only meet the demand on natural capital, but also to allow the natural capital consumed to be regenerated and all associated waste assimilated.

Currently we are in overshoot. The average global per capita footprint is 2.7 gha.The average global biocapacity is 1.8 gha per capita. That means humans need the earth to be another 50% bigger in order for it to be able to meet the demand on natural capital. At the current rate of increased consumption, the world will need to be three times as big to meet demand by 2050.

We are turning resources into waste faster than waste can be turned back into resources and depleting the very resources on which human life and biodiversity depend.The result is collapsing fisheries, diminishing forest cover, depletion of fresh water systems, and the build-up of carbon dioxide emission. Overshoot also contributes to resource conflicts and wars, mass migrations, famine, disease and other human tragedies and tends to have a disproportionate impact on the poor, who cannot buy their way out of the problem by getting resources from somewhere else.

So what is the impact of the extra 655,000 people on earth in the 3 day period? All we have to do is multiply the net increase in people by the average per capita gha (i.e 655,000 x 2.7 gha) which equals 1,768,500 gha. This is how much extra global hectares are needed. Over a year it will be 216 million gha (80 million extra people x 2.7 gha). The “I” in IPAT must therefore increase by the same amount and is reflected as an extra 216 million gha in overshoot.

The next variable in IPAT is affluence. This is where one looks at not only the bigger consumersin the west, but also the rise of the middle class in economies such as China and India. Worldwide 700,000 TV sets and 5 million phones have been sold in the last 24 hours. For the year, 20 million cars have been manufactured and 85 million computers have been sold. Just today, 5 billion dollars has been spent on the military enterprise.

In both China and India, the average per capita income has increased significantly in the last 30 years and is reflected in the rise of the middle class. Over this period the average per capita gha in China has risen from 1.3 gha to 2.2 gha now. In India it has risen from 0.7 gha to 0.9 gha over the same period. Worryingly, India’s biocapacity has collapsed in the same period by almost half down to 0.4 gha per person. This means it is regenerating its own natural capital at half the previous rate.