Sustainable Development - video4 - Human impact: The IPAT equation

This video considers a model of human impact proposed by Ehrlich and Holdren called the "IPAT" equation. It reveals its underlying assumptions and the additional opportunities for reducing impact.

Human impact, the IPAT equation.

What is the IPAT equation? What are the assumptions within it? And what opportunities to reduce impact does it reveal?

These are the questions that we’ll be looking at in this video.

In the early nineteen seventies scientists in the United States were attempting to calculate the impact of humans on the environment.

One of the methods proposed by Erhlich Holdren is called the IPAT equation.

In this equation the environmental impact was proposed to be a product of the population, the affluence of the population, and the technology.

Let's look more closely at this model. The mental model presumes that each person represents a consumer of economic goods and services.

The affluence term represents the economic goods and services that are able to be consumed per person.

The technology term represents the pollutants emitted per economic good or service consumed.

One line of reasoning that arose from the IPAT equation was that countries of large populations, such as China and India,

who together comprise more than a third of the world's people are the countries with largest negative impact;

however, the affluence term has proved to be far more important.

For example, wealthier countries have five times the ecological footprint then developing countries have.

A simplified way of strategizing to reduce the impact would be to manipulate the terms on the right-hand side of the equation;

however, in some cases there are serious ethical considerations in doing this.

For example, it is clear that reducing the population would decrease the impact,

but manipulating individuals reproductive rights or deciding to end the lives of people are serious moral infractions.

As a technologist the term in the IPAT equation that makes most sense as an intervention point is the technology term.

Within the technology term we have the opportunity of developing products and services

that have a much reduced impact throughout the lifecycle.

This is encouraging but gains in efficiency of a particular process are mathematically bound by the laws of thermodynamics.

That is, you can't get a process that is more than a hundred percent energy-efficient,

so the impact for technology term has limits within a particular technology.

What else can be done? One way to create more options for high-impact interventions is to expand the boundaries of the problem.

In this image we use the notation of causal loop diagrams to show how the IPAT variables are influenced by a number of other variables.

Each arrow shows a causal connection, for example, sustainable development in a society is correlated with greater gender equity,

which leads to lower birth rates and reduced population.

While technology efficiency is limited by the laws of thermodynamics things like

gender equity, literacy, art, ethics, spirituality, are not mathematically limited.

These areas of intervention do not necessarily require new investments of energy or materials

but do require an attention to the human influences of the system behavior.

One of the dangers of viewing the system this way is in assuming that people are objects

that can be manipulated to produce a desired sustainable effect.

In this scenario the designer is using people to achieve an outcome.

An alternative is to create partnerships where people can work together to choose their shared destiny.

Participatory action methods of design are in the spirit of creating shared outcomes through individually and collectively chosen actions.

The IPAT equation is a simple way of conceptualizing the environmental impact of a human population and its lifestyle.

It represents humans as consumers whose impact is a product of their affluence

and the pollution associated with the technology to support their consumption.

The IPAT reveals that opportunities to reduce impact come from both technology

and many other interventions that influence population, affluence and technology.

These interventions call for participatory action towards shared aspirations.