Limits to Growth: The 30-Year UpdateMeadows, Randers, Meadows

ISBN 1-931498-58-X

And Why Systems Thinking is Imperative in the Field of Sustainability Management

BackgroundClub of Rome formed in 1968, by

Aurelio Peccei – founder of Alitalia Addressed

◦Poverty, war, pollution, crime, oppression, resource depletion, terrorism, economic instability, racism

1970 - invited Jay Forrester, MIT, to find interrelated world’s problems

1975 --Created World Model computer simulation showed world collapse based on System Thinking premises

BackgroundDonella and Dennis Meadows

joined the team in 1971 to create models based on:◦Population◦Industry◦Agriculture◦Natural resources◦Environment

Created the World 2 model key interconnectedness of socioeconomic systems

FindingsCarrying capacity of the planet

cannot sustain population and capital growth

“The only option is to choose our limits or nature will choose them for us”

“Exponential growth. What the world sees as solutions to problems is in fact a root cause of the problem” – J. Forrester

Called before US Congress to explain its model. Original text read by all global heads of state

Overshoot Defined = Overshoot is to go too

far or beyond limits accidentally 3 Causes

1. Growth, acceleration, rapid change2. Limits or barriers3. Delay in perception - and response

- to keep system within its limits

System DynamicsPopulation GrowthMaterial economyIn relation to Exceeding capacity of the

planet’s natural resourcesThere’s a disconnect: Pricing and

capital cannot be sustained to continue to reap natural resources

Predictable Outcomes?

1. “Crash” – Depleted Resources, Difficult Extraction of Resources, Too Expensive

2. A deliberate correction = a sustainable future

Methodologies used for LTG1. Standard scientific and

economic theories on global systems

2. Data on natural resources3. Computer models to project

implications4. Worldview – attitudes, beliefs,

values

What is a System?System Thinking – ForresterA system is the interconnected

set of elements that is coherently organized in a way that achieves something

1. Elements2. Interconnections3. Purpose

One Purpose = Interrelated Parts“Multiple Embedded Purposes”

PerhapsA University’s purpose is to

discover and preserve knowledgeThe purpose of the student is to

gain knowledge and obtain good grades

The purpose of the professors is to provide learning and research support

The purpose of the administration is to operate in a balanced budget

The ElementsElements change as part of living

system:◦Students graduate◦Professors retire◦Administrators turnover◦But the purpose remains the same

The system remains the sameYet if interconnections change,

the system does: ex. If students grade professors, decisions may be made through manipulation or coercion

Throughput/Stocks/SinksEvery system:

INFLOWSTOCK

OUTLFOW

RAINRIVER INFLOW

RESERVOIR EVAPORATIONDISCHARGE

Important PrinciplesEvery system:

1. Stocks Rise as Inflows Exceed Outflow

2. Stocks Fall as Outflows Exceed Inflow3. Dynamic Equilibrium if Inflow =

Outflow

INFLOWSTOCK

OUTLFOW

Systems ThinkingComprises Feedback LoopsChanges to the stock are caused

by flows to the same stockReinforcing feedback loops =

exponential growth or runaway decay

What Does It Look Like?Perhaps, a population imbalance

BIRTHSPOPULATION

DEATHS

FERTILITY MORTALITY

R (-)B (+)

Dynamics of Growth - Finite World

World3 Model◦Tracks stocks and flows – MEASURES,

ACTSStocks = population, industrial

capital, pollution, cultivated landThroughput flows – birth and

death rates, investment and depreciation, rates pollution generated and assimilated, land erosion and development, land removed for urban or industrial use rate

Limits to ThroughputEnergy and materials needed to

keep people, cars, houses, and factories functioning:

Sources and sinksWhat is driving the factors?

Sources Materials & Fuels Use

Waste in the Environment

Resource Use Rate

Emissions rate

Limits: A Human Choice: Linear

Economic Sources

• Extraction / Production - sources

• Material Economy

Society

Environment

• Consumption• Waste streams and

pollutants

Sinks:

Can’t be absorbed

• Waste• Toxins to air, water, land,

landfills

Chapter 2: Exponential GrowthPhysical growth on a finite planet

must eventually end. The World3 Model aims to define

exponential growth based on a system of human population and economic growth

Models time and interconnectionsOvershoot is caused by growth,

acceleration, rapid change

World3 Model - SimulationsKey features1. Growth process2. Limits3. Delays4. Erosion process

5. Reinforcing + and – balancing feedback loops or causal loops

6. Contributing and counteracting

World3Forecasts time to change based

on variable feedback loops

Developed to:◦ understand how the future can look◦ assess behavior patterns◦ and how the humans will interact

with the carrying capacity of the planet

What is Exponential Growth?Process of doubling, quadrupling,

etc. Linear growth increases at a

constant rate

Exponential growth can “sneak up on you” or become a surprise

Savings vs. putting money in jar◦Jar = linear. What you put in is what

you have.◦Account = compounded interest

earned

Drivers

For human society the drivers are:1. Population Growth2. Productive Capital Drive food production, resource

use, energy production, and pollution

Profound changes in consumption behavior can influence efficient use of resources – think “marketing” here

I. World Population – 7.1 BThe gap between birth and death rates

determines the rate at which population grows. 1 Billion ~ 12 years◦Rapid exponential growth in world

population will increase from 7B to 9.3B by 2050 (US Bureau of Census) Sub-Saharan Africa – double population in 10 yrs Northern India – expected to be 1.6B in 2050 Europe: average birth rate 1.2 per family USA – average birth rate 2 per family Japan – decline 1:3 will be elderly for next 30 yrs

Additions to World PopulationYear Population

(millions)Growth Rate People

Added (millions)

1970 3,690 1.93 71

1980 4,430 1.70 75

1990 5,250 1.49 78

2000 6,060 1.23 75

Growth rate is declining due to fewer deaths and increased births. (Difference between Birth and Mortality rate)

Thus, population continues to increase at a rate in countries that cannot sustain productive capital.

People, Poverty, More PeopleWhat have you experienced

regarding the gap between the rich and the poor?

Population growth slows economic growth and keeps people in conditions of poverty

Produce more food for more people results in destruction of arable land

Let’s BrainstormHow can we slow population

growth humanely?

Sources and SinksIncrease in energy and capital

needed to sustain growing population vs exhaustion of materials

2 main categories to sustain economic and population growth1. Physical needs - biological and

industrial2. Social needs: stability, peace,

security, long-term decision makers, education, innovation

STUDY Page 49 to learn to evaluate system sources and sinks

II. Productive Capital = OvershootHumans using materials and

producing wastes at rates that are not sustainable

Human burden on natural environment already in overshoot

True costs of material are increasing

Ecological Economist: Herman Daly

3 Rules to Define Sustainable Limits to material and energy throughput….1. Renewable resources = not depleted

faster than replenishment rate allows2. Nonrenewable resource = usage

doesn’t exceed renewable substitute or profits put back into renewable

3. Pollutants = rate of emissions not greater than can be absorbed, recycled, filtered

Let’s DiscussWhat is your understanding of

how humans are using critical resources at an unsustainable rate? What are some examples?

How will you recognize the peak?

IPAT formulaImpact = Population X Affluence X

Technology(damage done by use of technologies

chosen by the affluent)

Population X cup/person X water + soap /cups per year

X KwH/kg water + soap X CO2, NOx, land use / Kwh

Scenarios

1. Primary goal is never-ending growth

2. Population will stop growing when rich

3. Economy stops growing when we run into limits

Our Task Force Teams in class will look at such topics asRenewable Sources

◦Food, Land, Soil◦Water◦Forests◦Ecosystems (species and extinction)

Nonrenewable Sources◦Fossil fuels, natural gas, hydrogen

liquid◦Nuclear energy, renewable energy

sources◦Materials extraction

Societal Approaches & Potential Outcomes

1. Grow without interruption2. Level off within capacity (?)3. Overshoot carrying capacity

without doing permanent damage

4. Overshoot with severe damage to resources (Outcome of this?)

Forces population and economy to decline to right size

Which stage do you think the USA is in?

We are already beyond the carrying capacity of planet

The models project collapse

Communicating Complex Info“The systems limits are not only

finite, but erodible when overstressed/used”

“Rising population gives signals of stress that are often ignored or action is delayed”

“There are physical limits to sources of materials and energy that sustain the economy and population”

What can we do?Growth in capital and population

must be slowedDematerialization, lifestyle

changes, energy sources for both rich and poor

Sources and sinks conserved and restored

Society must derive long-term solutions

Prevent and restore erosion

Steps to Problem SolvingDraw the current state value chainIdentify sources and sinksIdentify problems and long term

ramifications currently occurringDraw the current system feedback

loops based on the problems identified

Identify how to bring the system back to equilibrium

Draw the balancing loopsDraw unintended consequences of

balancing the system – i.e. who loses?