Urgency to Act and the IPAT

Urgency to Act

• —   “Spaceshipearth carrying capacity to sustain life will be soon exceeded”
•  —  Theworlds population exceeds 6 billion, and 80 million people are added each year.Resource consumption per capita also is in the rise. For example, over 25percent of the possible terrestrial and aquatic solar energy captured inphotosynthesis by primary producers (plants and cyanobacteria) in nowappropriated by humans. Just two more doublings of the human impact on theworlds natural resources – through a combination of population increase andconsumption-fueled economic growth – would result in 100 percent of the netprimary production being utilized by humans.

Carrying Capacity

Refers to the upper limit to population or community sizeimposed through environmental resistance (availability of renewable landnon-renewable resources)

Renewable resources are those that can be  produced for consumption

Non-renewable resources are resources that are finite suchas space and could not be produced- once used, it could not be recreated

In the past, society evolved with the principle of “fightingagainst limits rather than learning to live with them.” ( The Limits to Growth,Meadows, et.al, 1972)

IPAT equation

                                I= P * A * T

(Environmental Economic model of Paul Ehrlich and JohnHoldren Ehrlich Identity )

Human Impacts on the Environment (I) can be estimatedfrom three (3) general factors:

The number of people (P)

Resources consumed per person (A for"affluence")

Effects of the Technologies used to obtain those resources (T)

The impact of any group or nation on the environment isrepresented qualitatively by P*A*T

“I = P * A * T” where ‘I=environmental impact’  ‘P=population,’  ‘A=affluence’ ‘T=technology’ expresses that growth in population, affluence, andtechnology are jointly responsible for environmental problems

Example: Multiply the population (P) times the number ofcars per person (A) times the average CO₂ emissions per user (T)

Existing and Emerging Environmental Issues

•  —  Globalization,Trade, and Development
•  —  Copingwith climate change and viability
•  —  Growthof megacities
•  —  Humanvulnerability to climate change
•  —  Freshwaterdepletion and degradation
•  —  Marineand Coastal degradation
•  —  Populationgrowth
•  —  Risingconsumption in developing countries
•  —  Bio-diversitydepletion
• —   Bio-security

Source: United Nations Environment Programme, 2002

We have to act urgently

As population and per capita consumption increase, so doesthe urgency for architects/ professionals/ ordinary persons to protectand enhance the environments and communities where people reside.

Role of Engineers

It has a unique role to play, because they have a directeffect to on the design and development of products, processes, andsystems, as well as on natural ecosystems through material selection,project siting, and the end-of-life handling of products.

(adopted from Environmental Engineering by James R. Milhelcand Julie Beth Zimmerman)