IINTEGRATEDNTEGRATED ASSESSMENTASSESSMENT, , WATERWATERRESOURCESRESOURCES ANDAND SCIENCESCIENCE--POLICYPOLICYRESOURCESRESOURCES, , ANDAND SCIENCESCIENCE--POLICYPOLICY

COMMUNICATIONCOMMUNICATION

Evan G.R. DaviesMohammad Khaled Akhtar

Gordon McBeanSlobodan P SimonovicSlobodan P. Simonovic

The University of Western Ontarioy

OOUTLINEUTLINE

Research GoalsModel Development

StructureEquations

Simulation & ExperimentationSimulation & ExperimentationConclusions

BBACKGROUNDACKGROUND

The climate is changingg g

People are partially responsible

Impacts of higher GHG concentrations:

“Large-scale, high-impact, non-linear, and potentially abrupt and irreversible changes in physical and abrupt and irreversible changes in physical and biological systems”

Source: Intergovernmental Panel on Climate Change (IPCC, 2001)

RRRRESEARCHESEARCH GOALSGOALS

Society

1. Examine how climate change affects long-term sustainability

EconomyEnvironment

2. Provide a tool to policy-makers

3 Stress importance of feedbacks3. Stress importance of feedbacksClimate Change Social

Adaptation

Understanding better policy

CCLIMATELIMATE CHANGECHANGE MODELLINGMODELLING

The usual approach:The usual approach:‘Drive’ complex model with emissions scenarios

The problem:The problem:These systems are interdependent

OOURUR APPROACHAPPROACH

The reality:Interaction between socio economic and natural Interaction between socio-economic and natural systems causes climate change

l h l dClimate Change Social Adaptation

Interaction determines the entire system’s evolutionevolution

MMETHODOLOGYETHODOLOGY

System Dynamics (modelling)Explicit modelling of feedbacksExplicit modelling of feedbacksFor systems with dynamic complexityImproves understanding of system behaviourImproves understanding of system behaviourModels the most important processesF d t di t di tiFocuses on understanding, not on prediction

SSYSTEMYSTEM DYNAMICSDYNAMICS APPROACHAPPROACHSSYSTEMYSTEM DYNAMICSDYNAMICS APPROACHAPPROACH

A rigorous method of system description, which facilitates feedback analysis usually via a simulation model of the effects of alternative system structure and control policies on system system structure and control policies on system behavior.

SSYSTEMYSTEM DYNAMICSDYNAMICS APPROACHAPPROACHSSYSTEMYSTEM DYNAMICSDYNAMICS APPROACHAPPROACH

Feedback Processes: Two kinds only

Positive = reinforcing

money200,000

150,000

100,000

50,000

00 10 20 30 40 50 60 70 80 90 100

Time (Year)

Negative = balancing

State100

75

50

25

00 5 10 15 20 25 30 35 40 45 50

Time (Second)

But when they combine …

1

1

1

1 1 1

1

1

1

MMMMODELODEL STRUCTURESTRUCTURE

Carbon cycle Land Use CarbonCarbon

+

AtmosphericCarbon cycleClimateWater Demand

Land Use Emissions

+ Land UseLand Use

Atmospheric CO2

EconomyEconomy

Temperature

+Carbon AbsorptionAtmospheric [CO2]Temperature Change

+− Industrial

emission

Water QualitySurface Flow

Clearing and

Burning ClimateClimate

Consumption and Labour

GDP per

+Water Use

Wastewater treatment and reuse EnergyEnergy

+

Energy Demand Intensity

Water use ffi i

PopulationLand Use

+PopulationPopulation

-

capita

+ Water QualityWater QualityWater Demand/UseWater Demand/Use

Wastewater

WastewaterReuse

−Water scarcityRenewable flow in changing climatePopulation growth = f(water scarcity)Biome coverage

+

Water use Intensity

+

efficiency

EconomyEnergy

+

TemperatureWater Stress

Surface Water AvailabilityWater

Consumption

WastewaterTreatment

WastewaterTreatment and

Reuse

( y)Biome coverageHuman action

GDP changeCarbon taxIndustrial emission

−

10

+Surface FlowSurface Flow

Reuse− +Emissions

Water UseEnergy demand

MMODELODEL SECTORSSECTORS

1 Carbon Cycle1. Carbon Cycle2. Climate System3. Water Demand4. Water Quality5. Surface Flow

P l ti6. Population7. Land-use8 Economy8. Economy9. Energy

SSOMEOME EQUATIONSEQUATIONS

Climate System:Climate System:

Domestic Water Withdrawal:

( )[ ] dttLtStLEtLtLtFQtH outheatheatdownupaatm ⋅−++−++= ∫ )()()()()()()(Energy [1024 Joules]

Domestic Water Withdrawal:

Economic Sector:( )( )[ ]2)(/)(

maxmin 1)()( tPtGDPD eDSWIDSWItPtW γ−−+⋅=Volume [km3 yr-1]

Economic Sector:

Population growth:

( ) γγµ −⋅⋅⋅⋅−⋅Ω= 11 )()()()()(1)()( 2 tLtKtAttbttQ b

GDP [1012 $US yr-1]

Population growth:

C b i At h)()(

)()(

tgtrdtdr

twtabtg

⋅=

⋅=

Growth [people yr-1]

Carbon in Atmosphere:dtOEBBNPPDDDC flux

iLit

iB

iiLit

iHum

iCharatm ⋅⎥

⎦

⎤⎢⎣

⎡−+⎟

⎠

⎞⎜⎝

⎛++−⎟

⎠

⎞⎜⎝

⎛++= ∫ ∑∑∑∑∑∑

====== 6..16..16..16..16..16..1Mass [Gt C yr-1]

CCARBONARBON SECTORSECTOR CAUSALCAUSAL DIAGRAMDIAGRAM

Emissions

Legend Atmosphere Deep Ocean

Emissions

Decomposition

Emissions

Biomass

NPP

Litter Fall LitterLand Use

Oceanic AbsorptionHumus

Stable HumusStable Humus

CCARBONARBON SECTORSECTOR FLOWFLOW DIAGRAMDIAGRAMAtmospheric CO2

Concentration

CO2 in Atmosphere

<Pjk>

CO2 Emissions

<Current Biome

Industrial CarbonEmissions E(t)

Turn On HumanEmissions

Biomass

NPP

Litt f ll

Decayto

HumusDecayfrom

<Pjk>

<Sigma (NPPj)>

Unburnt

BurntBiomass

BurntLitter

<Biomass to Atm>

<Litter to Atm>

CumulativeEmissions

Fossil Fuel BurningBiome Area

<Current BiomeArea>

<Init Biome Area>

Litter

LitterfallfromLitter

Decayfrom

HumusHumification

Decayfrom

Charcoal

<Tao(Bjk)>

<Lambda j>

<Tao(Lj)>

Wood

BiomasstoLitt t

<Dead biomass toHumus>

<Litter Burnt intoCharcoal>

<Internal HumusFlows Calculation>

Turn On HumanLand Use

<Litter Q10>

Humus

Stable Humusand Charcoal

Carbonization

<Phi j>

<Tao(Hj)>

T (Kj)

toCharcoalLitter to

Charcoal

<Burnt Biomass toCharcoal>

Internal HumusFlows

Internal Charcoal

<Humus Q10>

<Charcoal Q10>

<Tao(Kj)> Internal CharcoalFlows

<Internal CharcoalFlows Calculation>

CCCCARBONARBON SECTORSECTOR EQUATIONSEQUATIONS

Atmosphere( ) dtFEBBNPPDDDDA OLBKHLB ⋅−+++−+++= ∫

Biomass

( )∫ ⋅−−−−−= dtUBBFKFHFLNPPB jkjkBjkBjkBjkBjkjk

Net Primary Productivity15)(

Root Decay

15101)( ×⋅⋅= jjjkjk SANPPpNPP σ

( )( )00 ln1)()( AANPPNPP jj βσσ +×=

y)( 4

44

j

jjB B

BFH τ=

15

KKEYEY VARIABLESVARIABLESKKEYEY VARIABLESVARIABLES

Atmospheric CO2Available surface waterAvailable surface waterBiome areasCO2 emissionsE i t t (GDP)Economic output (GDP)Land use changePopulationS f Surface temperatureWater withdrawals and consumptionWater stressWastewater treatment and reuseCarbon taxInvestment strategiesgSubsidization of the renewable energy Zero carbon emission technology

MMMMODELODEL COMPLEXITYCOMPLEXITY

Number of Model Elements:740 variables

‘Variables’: ~1600 (incl. arrays)C 470 (i l )

Sector # of VariablesCarbon: 130Energy & Economy: 205Climate: 80Constants: ~470 (incl. arrays)

230 Stocks (many in arrays)2300 total

Climate: 80Water Treatment: 50Water Demand: 45Hydro. Cycle: 45Land Use/Change: 15Population: 10

600 equations99 major equations

Thousands of feedbacksPopulation: 4468 loops Water stress: 2756 loopsEconomic output: 203 loopsIndustrial emissions: 47 loopsp

17

EEXAMPLEXAMPLE

Wastewater ReuseIndividual Simulation

H t ll ti ff t t il bilitHow water pollution affects water availabilityHow water stress affects population growth

A C Approach: Compare experiment against base case results

18

EEXAMPLEXAMPLEEEXAMPLEXAMPLE

Untreated Returnable WatersTreated Returnable Waters1,468

1,164

860 82

976.99

751.00

525 01 860.82

556.74

252.67

525.01

299.03

73.041960 1974 1988 2002 2016 2030 2044 2058 2072 2086 2100

Time (Year)

Untreated Returnable Waters : Base km*km*km/YearUntreated Returnable Waters : No Treatment or Reuse km*km*km/Year

1960 1974 1988 2002 2016 2030 2044 2058 2072 2086 2100Time (Year)

Treated Returnable Waters : Base km*km*km/YearTreated Returnable Waters : No Treatment or Reuse km*km*km/Year

Less wastewater treatment - more pollutionMore pollution - less clean water available

EEXAMPLEXAMPLEPopulation

11.73 B

9.554 B

Water Stress1.062

7.376 B

5.198 B

3.02 B

0.7227

0.38321960 1974 1988 2002 2016 2030 2044 2058 2072 2086 2100

Time (Year)

Population to Use : Base personPopulation to Use : No Treatment or Reuse person

1960 1974 1988 2002 2016 2030 2044 2058 2072 2086 2100Time (Year)

"Withdrawals to Availability ratio incl. Pollution Effects" : Base Dimensionless"Withdrawals to Availability ratio incl. Pollution Effects" : No Treatment or Reuse Dimensionless

Simulation interpretation:oTrue water scarcity level not perceived using general definition

oWater scarcity reaches critical level

oAction to reduce water stress too late, damage is done

CCONCLUSIONSONCLUSIONS ((FROMFROM EEXPERIMENTXPERIMENT))

Water sector modelling:Water Pollution increases Water StressWater Pollution increases Water StressHigh water stress dangerousReuse, treated wastewater to reduce water scarcity

CCONCLUSIONSONCLUSIONSCCONCLUSIONSONCLUSIONS

Cost of this approach:ppSacrifice resolution for completeness

Benefits of our approach:Represents socio-economic adaption as part of physical process of climate changephysical process of climate changeIncludes vital socio-economic feedbacksAllows policy analysis, fast simulation runs

A shift is underway from a global-aggregate to a regional representation of global change.regional representation of global change.

NNEXTEXT STEPSSTEPS ININ RESEARCHRESEARCH

R i li i f h l b l d lRegionalization of the global model

Improvements of the water sectorImprovements of the water sector

Questions?Questions?