Water Modeling in GCAM –

Key Accomplishments & Future Directions

Mohamad Hejazi

Jae Edmonds, Leon Clarke, Vaibhav Chaturvedi, Page Kyle, Evan Davies, Jiyong Eom, Pralit Patel, Marshall Wise, Sonny Kim, Kate Calvin

Joint Global Change Research Institute (JGCRI)

College Park, MD

Thursday September 20, 2012

Overview

Water in the Global Change Assessment Model (GCAM)

Global water availability – A global hydrologic model

Global water demands by sectors

Current and future estimates of water scarcity under a set of

alternative socioeconomic pathways

Their relative impacts on global water scarcity

Climate change (GCMs, emission pathways)

Socioeconomic drivers (population, income, technology, etc.)

Climate change mitigation policies (type, stringency)

2

Incorporating Water in GCAM

WATER WATER

► Energy ► Agriculture ► Domestic

► Energy ► Agriculture ► Domestic

Water Demand Water Demand

► Surface

► Ground

► Natural Lakes

► Surface

► Ground

► Natural Lakes

Water Supply Water Supply

► Water prices

► Water prices

Water Markets Water Markets

Land

Characteristics

Land

Characteristics

Climate Inputs Climate Inputs 3

WATER SUPPLY Model & Results

4

Water Supply – A Global Hydrologic Model

5 Climatic Research Unit (CRU), University of East Anglia Climatic Research Unit (CRU), University of East Anglia

The Effects of Climate Change on Runoff

(Percent Change between 2095 & 2005)

6

WATER DEMAND Model & Results

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Representation of all Components of

the Water Demand Sectors in GCAM

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Estimates of Global Water

Demands in 2005 & 2095

Global water demands by sector in years 2005 and 2095 (under three alternative scenarios with variations in technology, income, & population) 9

ALTERNATIVE

SOCIOECONOMIC SCENARIOS

Future Water Demand Results

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Socioeconomic

Scenarios

SIX SCENARIOS:

1. Collapse (POP6/MDG-)

2. Sustainability and Equity (POP6/MDG+)

3. Muddling Through (POP9/MDG-)

4. Consumerism (POP9/MDG+)

5. Crowded Chaos (POP14/MDG-)

6. Social Conservatism (POP14/MDG+)

Eom, J., et al. (2012), Scenarios of Future Socio-economics, Energy, Land Use and Radiative Forcing, in Robert G. Watt, Energy and Climate Change, In Preparation, edited.

Comparison among the six scenarios with respect to socioeconomics (e.g.: population, GDP and per capita income), climatic variables (e.g.: ΔT, radiative forcings, & CO2 concentration), land (e.g.: cropland area, biomass area), & energy (e.g.: electricity generation, & primary energy consumption) assumptions

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Global Water Withdrawal Distribution

for Six Alternative Scenarios

Global water withdrawal distribution for all six SSP scenarios and all water sectors In years 2005 and 2095; the circle diameter corresponds to the total annual withdrawal volume.

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Global Water Withdrawals vs.

Literature Estimates of Water Use

Sources: Gleick 2003 (and references therein), Falkenmark & Rockström, 2000, Alcamo et al. 2003a, Alcamo et al. 2003b, Shiklomanov & Rodda, 2003, Alcamo et al., 2007, Shen et al. 2008, Wada et al., 2011, and AQUASTAT 2011 13

Preliminary Assessment of Water Scarcity

Water scarcity in years 2005, 2050, and 2095 at the 14-GCAM regions due to changing water demands; total water supply (renewable water + desalinated water) are assumed fixed to 2005 levels to capture the effect of demand projection alone on water scarcity; the error-bars represent the range of values based on the six SSP scenarios; WSI values above 0.4 are considered severely stressed regions

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WATER SCARCITY Methodology & Results

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Impact Assessment: Water Scarcity

Domestic

Agriculture

(irrigation & livestock)

Electricity

Generation

Primary Energy & Mining

Manufa-cturing

Global Water

Demand

For a given climate mitigation policy scenario & particular year:

Global gridded-map of total water

demands

Requirement: Downscale demands to grid scale

Global gridded-map of total water

demands

Requirement: Downscale demands to grid scale

Water Supply

Severe Stress:

0.4 ≤ WSI

Moderate Stress:

0.2 ≤ WSI < 0.4

Low Stress:

0.1 ≤ WSI < 0.2

No Stress:

WSI < 0.1

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Water Scarcity in 2005

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Water Scarcity in 2095

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Change in Water Scarcity

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IMPACT OF CLIMATE POLICY &

SOCIOECONOMIC DRIVERS

Methodology & Results

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Consistent World of Water

Demand & Supply in GCAM

4 GCMs 4 GCMs

Hydrology Hydrology

Force GCAM to reproduce the above radiative forcing pathways using:

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Global Water Demands

Global Accessible Water (10,150 km3/yr) Postel et al. (1996)

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Relative Impacts

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The Effects of Climate Change

Mitigation Policies on Water Scarcity

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Percent of Population Living under Severe Water Scarcity Conditions in Year 2095 under Different Climate Policies

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Global Population Living under Different

Thresholds of Water Scarcity Conditions

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The Effects of Socioeconomic Drivers

on Water Scarcity in 2050

Shifts in the Cumulative Density Function of Global Population in 2050 27

The Effects of Socioeconomic Drivers

on Water Scarcity in 2050

Shifts in the Cumulative Density Function of Global Population in 2095 28

CLIMATE CHANGE VS.

SOCIOECONOMIC DRIVERS

Methodology & Results

29

Experiments

B1 (RF4.2) B2 (RF5.5) A2 (RF7.7) A1Fi (RF8.8)

Variable Climate2095, B1 Climate2095, B2 Climate2095, A2 Climate2095, A1Fi

Fixed Demand2005 Demand2005 Demand2005 Demand2005

B1 (RF4.2) B2 (RF5.5) A2 (RF7.7) A1Fi (RF8.8)

Fixed Climate2005 Climate2005 Climate2005 Climate2005

Variable Demand2095, 6- Demand2095, 6+ Demand2095, 9+ Demand2095, 14-

Baseline: current demands and current climate conditions in year 2005

The effect of climate change alone

The effect of socioeconomic drivers alone

The effects of climate change and socioeconomic drivers together

B1 (RF4.2) B2 (RF5.5) A2 (RF7.7) A1Fi (RF8.8)

Variable Climate2095, B1 Climate2095, B2 Climate2095, A2 Climate2095, A1Fi

Variable Demand2095, 6- Demand2095, 6+ Demand2095, 9+ Demand2095, 14-

Baseline

Fixed Climate2005

Fixed Demand2005

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Fixing Socioeconomics &

Changing Climate

B1 (RF2095=4.2 W/m2) B2 (RF2095=5.5 W/m2)

A2 (RF2095=7.7 W/m2) A1Fi (RF2095=8.8 W/m2)

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B1 (RF2095=4.2 W/m2) B2 (RF2095=5.5 W/m2)

A2 (RF2095=7.7 W/m2) A1Fi (RF2095=8.8 W/m2)

Changing Socioeconomics &

Fixing Climate

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B1 (RF2095=4.2 W/m2) B2 (RF2095=5.5 W/m2)

A2 (RF2095=7.7 W/m2) A1Fi (RF2095=8.8 W/m2)

Changing Socioeconomics

& Climate

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Difference from Year 2005

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Climate Change Vs.

Socioeconomic Drivers

35

Climate Change Vs. Socioeconomic Drivers

Basin Scale

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Future Research Directions

Allocating water among competing water users

and technology choices (two-way feedback)

Climate change impacts on water demands

Enhance the existing representations of the

global hydrologic model and demand sectors in

GCAM

Accounting for non-renewable water sources,

e.g., desalinated water and non-renewable (fossil)

groundwater

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QUESTIONS!

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References

Hejazi, Mohamad I., Jae Edmonds, and Vaibhav Chaturvedi (in press). Global irrigation demand – A

holistic approach, Journal of Irrigation & Drainage Systems Engineering.

Hejazi, Mohamad I., Jae Edmonds, and Vaibhav Chaturvedi, Evan Davies, and Jiyong Eom

(accepted). Scenarios of Global Municipal Water Use Demand Projections over the 21st Century,

Hydrological Sciences Journal.

Davies, Evan G. R., Page Kyle, and James A. Edmonds (in review). An integrated assessment of

global and regional water demands for electricity generation to 2095. Advances in Water Resources.

Kyle, Page, Evan Davies, James J Dooley, Steven J Smith, Leon E Clarke, James A Edmonds, and

Mohamad Hejazi (in review). Influence of climate change mitigation technology on global demands of

water for electricity generation. International Journal of Greenhouse Gas Control.

Hejazi, Mohamad I., James Edmonds, Leon Clarke, Page Kyle, Evan Davies, Vaibhav Chaturvedi,

Marshall Wise, Pralit Patel, Jiyong Eom, Katherine Calvin, Richard Moss, and Son Kim (in review).

Long-term global water use projections using six socioeconomic scenarios in an integrated assessment

modeling framework, Global Environmental Change. Part A, Human and Policy Dimensions.

Chaturvedi, Vaibhav, Mohamad Hejazi, James Edmonds, Leon Clarke, Page Kyle, Evan Davies,

Marshall Wise, and Katherine Calvin. Impact of emission mitigation policies on long term global

agricultural water demand. To be submitted to Climate Policy.

Hejazi, Mohamad I., James Edmonds, Leon Clarke, Page Kyle, Evan Davies, Vaibhav Chaturvedi,

Marshall Wise, Pralit Patel, Jiyong Eom, and Katherine Calvin. Integrated assessment of global water

scarcity over the 21st century: Global water supply and demand under extreme radiative forcing. To be

submitted to Hydrology and Earth System Sciences.

Hejazi, Mohamad I., James Edmonds, Leon Clarke, Page Kyle, Evan Davies, Vaibhav Chaturvedi,

Jiyong Eom, Marshall Wise, Pralit Patel, and Katherine Calvin. Integrated assessment of global water

scarcity over the 21st century: 2- Climate change mitigation policies. To be submitted to Hydrology and

Earth System Sciences. 39