A Complex Systems Study of the Implications

8/3/2019 A Complex Systems Study of the Implications

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A Complex Systems Study of the Implications of

Anthropogenic Perturbations of the Global

Biogeochemical Cycles

A PhD Presentation by Nicola Smith

23 May 2008


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During the 20th century the worlds

population quadrupled, the global economyexpanded 14-fold, energy use increased 16

times, and the control of world biomass

increased to about 40 percent


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Overview of PresentationOverview of Presentation

Describe research topic and key aims

Provide context to the proposed research a

summary of five existing contributions

Propose a broad conceptual framework

Describe the economic components of the

researchSummary of key challenges


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Overview of ResearchOverview of Research

Key task is to develop an integratedmodel of theEarth system that captures insights from both thenatural and social sciencesFocus is on:

Natural systems - biogeochemical cyclesSocio-economic systems - economy, demographicsThe interactions within and between thesecomponents

Research will pick up on contributions alreadymade by Murray Patterson and Garry McDonaldResearch will be undertaken at a globallevel


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Key Research AimsKey Research Aims

To develop a method for modelling the world economyas it is embedded within the global biogeochemicalcycles, that:

Achieves a high level of integration of natural and humancomponents

Captures important feedbacks, non-linearities and lags

To identify the anthropogenic disturbance regimes andperturbations that matter at the global level

The human mind is not well-adapted to interpreting the

behaviour of our complex earth system characterised bymultiple non-linear feedbacks Jay Forrester

To identify sustainable pathways for the globaleconomy


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What are Sustainable Pathways?What are Sustainable Pathways?

A steady state economy - in terms of physicalinput and output

Minimizing energy throughput (entropy law)A sustainable economy is one characterised by minimized and

consistent physical exchanges between human society and theenvironment, with internal material loops driven by renewableenergy

Maintaining a constant stock of (natural) capital(some natural capital is critical)

Maintain life-support services and assimilativecapacity of the environment

Ensuring the Earth system does not transcend toa new stable state


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Overview ofOther ModelsOverview ofOther Models

Integrated global modelling originates from the

1970s with theWorld2 and World3 models

Nearly all models begin with a strong emphasis

on either natural or human parts of the earth

system truly integrated models still rare

Five models have been selected for review to

help provide a context to the proposed research:Mackenzie, GBCM,World Model, GUMBO and

TARGETS


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Mackenzie ModelMackenzie Model

Mackenzie et al. (1993)

Strengths:

Attempt to integrate biogeochemical cycles (C, N andP) at a global level

Relatively simple and easy to understand

Limitations:

Few connections and feedbacks between cycles Largely driven by perturbations in P cycle only

Almost every process controlled by first order rateequation eg AO

f kA!

fAO = flux of C from atmosphere to ocean, k= constant,

A = C stock in atmosphere


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Global Biogeochemical Cycling ModelGlobal Biogeochemical Cycling Model

(GBCM)(GBCM)

Strengths:Very high degree of integration and feedback

between the biogeochemical cycles

eg phytoplankton N fixation

Limitations:

Every process driven by a selected donor stock

Does not include anthropogenic processes

2 2 4 4 2 2 100 150 80 4 2CO H O SO HPO N O N C H O N SP O H

p

C cycle H cycle

S cycleN cycle

P cycle


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LeontiefsWorld ModelLeontiefsWorld Model

What is input-output analysis?Example Input-Output Table

Primary Secondary Tertiary

Households

(final

demand)

Total

Outputs

Primary $5 $20 $1 $9 $35

Secondary $10 $5 $10 $25 $50

Tertiary $8 $10 $10 $12 $40

Primary Inputs $12 $15 $25

Total Inputs $35 $50 $40

Industries

Industries

Allows for easy consideration of economy structure,direct & indirect effects, industrial metabolism


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LeontiefsWorld Model (continued)LeontiefsWorld Model (continued)

First created by Leontief & colleagues in mid 1970sExtended in other studies eg Duchin and Lange (1994)

Strengths:

Describes economy with high level of detail (c50

sectors, 16 regions)

Recognises the industrial metabolism of the

economy (6 resource inputs and 3 residuals)

Limitations:Mostly linear relationships, few feedbacks

No internal description of natural systems

Highlights the difficulty of technology change


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GUMBO ModelGUMBO Model

Connects social, economic and biophysical systemsFocus is on ecosystem services

Strengths:

Many aspects of the Earth system included:

C, N and H2O cycles, climate, capital formation, GWP, land use,energy use, population

Recognises the industrial metabolism of economy

Considers role of the natural systems in economic

growthLimitations:

Entire economy aggregated to 1 sector

=GWP H S B W N E F J K P


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TARGETS FrameworkTARGETS Framework

Temperature increase, UV-B impact

Land cover,Livestock water demand, demandfor irrigated cropland

TERRA Sub-Model

CYCLES Sub-model

De mand Module State Module Land cover, Erosion State Module (calculates reservoirs and fluxes of biogeochemical cycles)

vegetable

animal product

roundwood

Potential yeild

Policy Module Soil fertility, Temperature

Scenarios covering: Area CO2 fertilization

Forest clearing of arabl e Land

Irrigati on land degradation

Land requirements Reforestation

for biofuel Land conservation Developed & Greenhouse gas, C & Br conc

production undeveloped GWP Temp sulphate & DMS conc UV-B effects

feedbacks Ozone module

Climate change module Stratospheric ozone

Radiative forcing Ozone conc

Ava il ab le E ne rgy e mi ss io ns Me an gl ob al t em pe ra tu re

food Population size (developed,

developing)

Energy Sub-Model Economic scenario generator

Temp effects (sea leve l) Do me sti c & i nd us tr ia l w as te wa te r tre atm en t

N & P conce ntratios in Hydrol ogical trans port

Energy Demand Module Electricity Modules Required investment in Required investment in surface & ground water of substances

Aggregate heat and electricity Investment in new capacity energy water resources

demand in 5sectors (commercial, Generating costs AQUA Sub-model

i nd us tr ia l, re si de nt ia l, tr an sp or t & E le ct ri ci ty pr ic e

other Electricity generation GWP, Industrial production,Water Water demand module Water State Module

Investment in efficiency gains investment Water demand for domestic, takes &

Efficiency gains Sector value added agriculture and industrial sectors discharge

Health services, Health services demand Temp increase. Water saving efficiency

GWP UV-B impacts

Population and Health Sub-model Policy/ Response Module

Heat Fuels (Solid Fuel, Liquid Fuel, Gaseous Fuel) Modules Increase of public water supply &

Fuel market share Pressure Module State sanitation. Distribution of water takes

Investment in extraction, Extraction costs, Fuel Price Global Environmental change Water pricing

Known fuel reserves Income status Fertility

Fuel production literacy Population

Drinking water availability Disease Impact Module

Food availability Fresh water availability, public water supply &

sanitation, water for ecosystems

Response/ Policy Module

Population

Labour Food policy Population

costs Water policy

Health services Impact Module

Reproduction policy Population with

Population size and structure proper drinking

Disease burden water

Demand for new reservoirs

Water availability &

quality, Rain

erosivity factor

Food/ Feed

Supply

- Actualyield-Supply costs

CropPotentialYield

Model

(includes factors such

as erosion, irrigation,

temperature)

Land Use Dynamics

Modelsdistribution

ofland amongland

types

Atmosphere

(egCO2, N2O, sulphate aerosols)

Terrestrial Biosphere

(eg Cin vegetation,

inorganic N in soils)

Ocean

egC in plankton, dissolved S

Hydrologicalcycle

Water flows

between reservoirs

Water quality

Allocation of water

to classes according

to N & P conc


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TARGETS Framework (continued)TARGETS Framework (continued)

Strengths:Extensive coverage of the Earth system

C, N, S, P & hydrological cycles, climate, agriculture, land usechange, energy use, population, health

Some feedbacks from environment to socio-economicsystems

eg impact of CO2 fertilization on agricultural production

Incorporation of cultural dimensions

Limitations:

Complexity has led to a loss of transparency

Limited representation of the economy, only 2 sectors industries and services (but sub-models foragriculture and energy)


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SummarySummary

Mackenzie GBCM World Model GUMBO TARGETS My Model

Coverage C, N, P C, P, N, S x C, N C, N, S, P C, N, S, P

Complexity Low High n/a Mod Mod High

Hydrological

cycle x

Climate x x x

Resource

inputsx x Metals, energy

Water, ore,

fossil fuels,

organic matter

Water resources,

organic matter,

fossil fuels

Many

Residuals x xCO2, S & N

oxidesCO2, N, waste

animal & human

excre., CH4, CO2,

SO2, N

Many

Other

interactionsNatural capital

UVB, water quality,

CO2 fert, nutrients?

Coverage x x 48 sectors 1 sector 2 sectorsup to 57sectors?

Complexity n/a n/a Low Low Low Mod

Land use

changex x x

Energy x x

Demographics x x Scenario

Politicalx x

Scenario Scenario Scenario ScenarioCultural x x x x

Biogeo-

chemistry

NaturalSystems

Economics

HumanSystems

Interface


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Limits to pop growth

Residuals (eg CO2)

Demand Temp Forcing Agents

Limits to

production

Land

Demand

Available Matter Inputs (eg timber)

land Energy

The Earth System

Natural Processes

Climate

Radiation

Global Biogeochemical Cycles

Land Use

Energy

Biome Change

Population

Temperature, Precipitation

Economy

Atmosphere

OceanTerrestrial

Primary

ManufServices


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The Economic System (static)The Economic System (static)

Starting point is monetary input-output table

Next step is to extend the framework to a

static model of mass and energy flows

Like other physical input-output tables this

will:

Account for the metabolism of the economy

Recognize the law of conservation of mass

The model will be unique as materials will be

recorded as biogeochemical species


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The Economic SystemThe Economic System (static, continued)(static, continued)

Physical Input-Output Table -Tracing Fertilizer Production and Consumption

Primary Secondary TertiaryHhlds (final

demand)CO2 NO3

- Human

excrement

Total

Outputs

Primary 6kg 2kg 2kg 10kg

Secondary 4kg 2kg 6kg

Tertiary

Hhlds (primary

inputs)2kg 2kg

Residuals

Ma tte

rin p u ts

Industries

Industries

C 1kg

H2O 3kg

N2 1kg

CH4 1kg

Total Inputs 10kg 6kg 2kg

Ma tte

rin p u ts


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The Economic System (dynamic)The Economic System (dynamic)

A particularly challenging component of theresearch

Key factors to consider:

Population change

Change in capital

Technology change

Feedbacks from the environmentNo existing modeling approach entirelysatisfactory


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Modelling Economic DynamicsModelling Economic Dynamics

Input-Output Scenario-Based How do we incorporate

feedbacks?

CGE Models

Assumption of

equilibrium

Economic Growth TheoryOutput

Labour effectCapital effect

+ +

Technology

growth rate

Population

growth rateCapital

investment

++

+

Income+

Investmentrate

+

Wage rateRent rate

+ +

Capital

+

Output

Final

demands

Investment

Govt

spending

GDP+

++

+

Household

consump

Population

+

+

+


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ConclusionConclusion Key ChallengesKey Challenges

Breadth of topic

Scale and aggregation

How do we model dynamic growth of theeconomy?

How do we incorporate technologicalchange?

Complexity and comprehensiveness vseasily digestible outputs

Documents

A Complex Systems Study of the Implications