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Balancing clean water-climate change mitigation tradeoffs

Simon Parkinson1,2, Volker Krey1, Daniel Huppmann1, Taher Kahil1, David McCollum1,3, Oliver Fricko1, Edward A Byers1, Matthew Gidden1, Beatriz Mayor1, Zarrar Khan1,4, Catherine Raptis5, Narasimha D Rao1, Nils Johnson1, Yoshihide Wada1,6, Ned Djilali2, Keywan Riahi1,7,8

1 International Institute for Applied Systems Analysis, Schlossplatz 1, A-2361 Laxenburg, Austria

2 University of Victoria, PO Box 3055 STN CSC, V8W 3P6 Victoria BC, Canada

3 University of Tennessee,1640 Cumberland Avenue, 37996-3340 Knoxville TN, United States

4 Universidad Pontificia Comillas, Calle de Santa Cruz de Marcenado 26, 28015 Madrid, Spain

5 ETH Zurich, John-von-Neumann-Weg 9, 8093 Zurich, Switzerland


6 Utrecht University, PO Box 80.115, 3508 Utrecht, The Netherlands


7 TU Graz, Inffeldgasse 21, 8010 Graz, Austria

8 Colorado School of Mines, 1500 Illinois Street, Golden, CO 80401, USA

Table of Contents

Figures Page

Figure S1: Regional representation of the MESSAGE IAM. 3

Figure S2: Models for water access and treatment. 3

Figure S3: Global distribution of per capita urban and rural domestic withdrawals. 4 Figure S4: Delineation of static water-scarce basin ecological regions. 4 Figure S5: Historical build out of desalination capacity estimated in each MESSAGE region. 5 Figure S6: Lower bounds on recycling and desalination production in 2030. 5 Figure S7: Stylized water conservation curve and linear parameterization. 6 Figure S8: Regional irrigation withdrawal trajectories (after conservation). 6 Figure S9: Regional urban withdrawal trajectories (after conservation). 7 Figure S10: Regional urban return flow trajectories (after conservation). 7 Figure S11: Regional rural withdrawal trajectories (after conservation). 8 Figure S12: Regional rural return flow trajectories (after conservation). 8 Figure S13: Power plant cooling system shares estimated in 2010 at the river basin-scale. 9 Figure S14: Representation of the power plant cooling technologies in the MESSAGE IAM. 9 Figure S15: Water supply sector representation incorporated into the MESSAGE IAM. 10 Figure S16: Water sector costs in 2030 in each MESSAGE region and globally. 12 Figure S17: Water sector costs in 2070 in each MESSAGE region and globally. 13 Figure S18: Water supply mixture in 2030 for each MESSAGE region and globally. 14 Figure S19: Water supply mixture in 2070 for each MESSAGE region and globally. 15 Figure S20: Power generation mixture in 2070 for each MESSAGE region and globally. 16 Figure S21: Power generation mixture in 2070 for each MESSAGE region and globally. 17 Tables

Table S1: Countries included in the MESSAGE regions. 2

Table S2: Parameterization of cooling technology costs and electric efficiency. 10 Table S3: Parameterization of water supply and treatment technologies in MESSAGE. 11

Supplementary References 18

2

Table S1 Countries included in the MESSAGE macro-regions.

Region Definition (list of countries)

NAM North America

(Canada, Guam, Puerto Rico, United States of America, Virgin Islands)

WEU

Western Europe

(Andorra, Austria, Azores, Belgium, Canary Islands, Channel Islands, Cyprus, Denmark, Faeroe Islands, Finland, France, Germany, Gibraltar, Greece, Greenland, Iceland, Ireland, Isle of Man, Italy, Liechtenstein, Luxembourg, Madeira, Malta, Monaco, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland, Turkey, United Kingdom)

PAO Pacific OECD

(Australia, Japan, New Zealand)

EEU

Central and Eastern Europe

(Albania, Bosnia and Herzegovina, Bulgaria, Croatia, Czech Republic, The former Yugoslav Rep. of Macedonia, Hungary, Poland, Romania, Slovak Republic, Slovenia, Estonia, Latvia, Lithuania)

FSU

Former Soviet Union

(Armenia, Azerbaijan, Belarus, Georgia, Kazakhstan, Kyrgyzstan, Republic of Moldova, Russian Federation, Tajikistan, Turkmenistan, Ukraine, Uzbekistan)

CPA Centrally Planned Asia and China

(Cambodia, China (incl. Hong Kong), Korea (DPR), Laos (PDR), Mongolia, Viet Nam) SAS South Asia

(Afghanistan, Bangladesh, Bhutan, India, Maldives, Nepal, Pakistan, Sri Lanka)

PAS

Other Pacific Asia

(American Samoa, Brunei Darussalam, Fiji, French Polynesia, Gilbert-Kiribati, Indonesia, Malaysia, Myanmar, New Caledonia, Papua, New Guinea, Philippines, Republic of Korea, Singapore, Solomon Islands, Taiwan (China), Thailand, Tonga, Vanuatu, Western Samoa)

MEA

Middle East and North Africa

(Algeria, Bahrain, Egypt (Arab Republic), Iraq, Iran (Islamic Republic), Israel, Jordan, Kuwait, Lebanon, Libya/SPLAJ, Morocco, Oman, Qatar, Saudi Arabia, Sudan, Syria (Arab Republic), Tunisia, United Arab Emirates, Yemen)

LAM

Latin America and the Caribbean

(Antigua and Barbuda, Argentina, Bahamas, Barbados, Belize, Bermuda, Bolivia, Brazil, Chile, Colombia, Costa Rica, Cuba, Dominica, Dominican Republic, Ecuador, El Salvador, French Guyana, Grenada, Guadeloupe, Guatemala, Guyana, Haiti, Honduras, Jamaica, Martinique, Mexico, Netherlands Antilles, Nicaragua, Panama, Paraguay, Peru, Saint Kitts and Nevis, Santa Lucia, Saint Vincent and the Grenadines, Suriname, Trinidad and Tobago, Uruguay, Venezuela)

AFR

Sub-Saharan Africa

(Angola, Benin, Botswana, British Indian Ocean Territory, Burkina Faso, Burundi, Cameroon, Cape Verde, Central African Republic, Chad, Comoros, Cote d'Ivoire, Congo, Democratic Republic of Congo, Djibouti, Equatorial Guinea, Eritrea, Ethiopia, Gabon, Gambia, Ghana, Guinea, Guinea-Bissau, Kenya, Lesotho, Liberia, Madagascar, Malawi, Mali, Mauritania, Mauritius, Mozambique, Namibia, Niger, Nigeria, Reunion, Rwanda, Sao Tome and Principe, Senegal, Seychelles, Sierra Leone, Somalia, South Africa, Swaziland, Tanzania, Togo, Uganda, Zambia, Zimbabwe)

3

Figure S1: Regional representation of the MESSAGE integrated assessment model (IAM).

Figure S2: Models for water access and treatment. Logistic models fit between estimated national incomes for 2010 from Dellink et al. (2017) [1], and connection rates from Baum et al. (2013) [2]. In the baseline scenario, countries converge along an exponential path from the estimated historical level towards the modeled connection rate obtained with the future SSP-based income projections. The SDG6 scenarios feature explicit narratives used to set the connection rates directly (i.e., 100% piped water access and 50% wastewater treated by 2030). It is assumed that once a given segment of the population has access to piped water, that they also have access to wastewater collection.

AFR

Per Capita Income [ USD2010 ]

Population with Piped Water Access [ % ]

Per Capita Income [ USD2010 ]

Population with Wastewater Treatment [ % ]

4

Figure S3: Global distribution of per capita delivered water volumes in 2030 estimated for the urban and rural domestic sectors at 7.5 arc-minutes using the approach described in Parkinson et al. (2016) [3]. Domestic water demands are adjusted in the SDG6 pathways to ensure there is enough water allocated for decent living standards in all locations, which in this paper is translated to a minimum of 100 liters per day in urban areas and 50 liters per day in rural areas [4-6]. Lacking explicit data, the withdrawals and return-flows are adjusted assuming an average efficiency of 75% from source to end-user.

Figure S4: Delineation of water-stressed basin units (ecoregions) following Hoekstra et al. (2010) [7]. Water stress is calculated as the ratio of withdrawals to renewable water availability, and is estimated previously for each ecoregion using data from the WaterGAP global hydrological model [8].

0 100 300 500

0.00.20.40.60.81.0

Urban − 2030

Liters per day

Cumulative Population Distribution

0 100 300 500

0.00.20.40.60.81.0

Rural − 2030

Liters per day

Cumulative Population Distribution

Baseline SDG6

Low-stress Medium-stress High-stress

5

Figure S5: Historical build out of desalination capacity estimated in each MESSAGE region [9].

Figure S6: Lower bounds on recycling and desalination production in 2030 at 7.5 arc-minutes in the SSP2 scenario.

1970 1980 1990 2000 2010 Reverse Osmosis

Installed Capacity [ km3 per year ] 02468

1970 1980 1990 2000 2010 Thermal Process

02468

MESSAGE Region Sub−Saharan Africa Centrally Planned Asia Eastern EU Former Soviet Union

Latin America Middle East & N. Africa North America Pacific Oceanic

Pacific Asia South Asia Western EU

6

Figure S7: Water conservation curve and linear parameterization used to represent demand response and anticipated implementation costs for end-use conservation measures in MESSAGE. The curve is implemented in the linear program using the indicated step functions. Previous work quantified the impact of diverse conservation options and implementation costs, and generally show that conservation costs increase non-linearly and offset a limited fraction of water demand [10–13]. A maximum conservation potential in each sector representing 30 % of the baseline withdrawals is assumed in this study, and is a somewhat conservative interpretation of previous assessments that focus specifically on water conservation potentials for specific sectors [11-14]. Extending previous work estimating regional-scale water supply expansion costs, we use 0.3 USD per m3 to represent the average cost for conservation measures because this approximates the point at which it can be expected that investment switches to expanding yield from conventional raw surface and groundwater sources [15].

Figure S8: Regional irrigation withdrawal trajectories (after conservation).

𝑐𝑏

𝜃𝑛

𝑐3

𝑐2 𝑐1

𝜃2

𝜃3

𝜃1 𝑐3=4

5∙ 𝑐𝑏 𝑐2=2

5∙ 𝑐𝑏 𝑐1=1

5∙ 𝑐𝑏

𝜃3=1 6∙ 𝜃𝑛 𝜃2=1

3∙ 𝜃𝑛 𝜃1=1

2∙ 𝜃𝑛

Water Conservation

Cost

2020 2040 2060 2080

02004006008001000

Baseline

Year

Irrigation Withdrawal [ million cubic meters ]

2020 2040 2060 2080

02004006008001000

SDG6−Supply

Year

2020 2040 2060 2080

02004006008001000

SDG6−Efficiency

Year

AFR CPA EEU FSU LAM MEA NAM PAO PAS SAS WEU

7

Figure S9: Regional urban (municipal + manufacturing) withdrawal trajectories (after conservation).

Figure S10: Regional urban (municipal + manufacturing) return-flow trajectories (after conservation).

2020 2040 2060 2080

050100150200250

Baseline

Year

Urban Withdrawal [ million cubic meters ]

2020 2040 2060 2080

050100150200250

SDG6−Supply

Year

2020 2040 2060 2080

050100150200250

SDG6−Efficiency

Year

AFR CPA EEU FSU LAM MEA NAM PAO PAS SAS WEU

2020 2040 2060 2080

050100150200250

Baseline

Year

Urban Return Flow [ million cubic meters ]

2020 2040 2060 2080

050100150200250

SDG6−Supply

Year

2020 2040 2060 2080

050100150200250

SDG6−Efficiency

Year

AFR CPA EEU FSU LAM MEA NAM PAO PAS SAS WEU

8

Figure S11: Regional rural (municipal) withdrawal trajectories (after conservation).

Figure S12: Regional rural return-flow trajectories (after conservation).

2020 2040 2060 2080

01020304050

Baseline

Year

Rural Withdrawal [ million cubic meters ]

2020 2040 2060 2080

01020304050

SDG6−Supply

Year

2020 2040 2060 2080

01020304050

SDG6−Efficiency

Year

AFR CPA EEU FSU LAM MEA NAM PAO PAS SAS WEU

2020 2040 2060 2080

01020304050

Baseline

Year

Rural Return [ million cubic meters ]

2020 2040 2060 2080

01020304050

SDG6−Supply

Year

2020 2040 2060 2080

01020304050

SDG6−Efficiency

Year

AFR CPA EEU FSU LAM MEA NAM PAO PAS SAS WEU

9

Figure S13: Cooling system shares (fraction of total installed capacity) across all power plants for different cooling system types identified for spatial units representing the intersection of river basins and countries with the facility-level dataset presented in Raptis and Pfister (2016) [16]. Shares are computed for each type of power plant in MESSAGE, and used to define the historical cooling technology capacity. Where data does not exist, the average across all plant types depicted here is used.

Figure S14: Representation of the power plant cooling technologies in the MESSAGE framework. Power plant cooling is treated as a commodity in the model that must be supplied by specific cooling technologies with unique cost and efficiency impacts.

Once through cooling - freshwater

Once through cooling – sea water

Recirculating - freshwater

Air cooling

Seawater thermal pollution Seawater withdrawal

Other operational water requirements Parasitic electricity demand

Power Plant Technology

10

Table S2 Data for advanced cooling technology costs and electric efficiency. A range of data is identified from the indicated literature sources. Data labelled ‘Efficient’ is used to parameterize technologies in the SDG6-Efficiency scenario. All other scenarios use mid-range data labelled ‘Baseline’.

Cooling Technology Cycle Type Parameter Units Efficient Baseline Source(s)

Recirculating

1. Air cooling not included for nuclear power plants and carbon capture and storage technologies due to perceived implementation challenges.

2. Other operational costs for cooling systems are accounted for through its energy and water use and the fixed costs for power plants.

3. Efficiency penalty is applied to represent parasitic electricity consumption from additional cooling equipment.

Figure S15: Reduced-form water supply sector representation incorporated into the MESSAGE IAM. The depicted technologies or processes transform water into different qualities. Sectoral water withdrawals and (waste) return-flows are input to the model, excluding energy-related water use, which is accounted for and optimized in MESSAGE at the technology-level. Additional energy inputs and waste outputs for the technologies are included and link the water supply sector to the energy system modeled in MESSAGE. Saline Water Resources Freshwater Resources Urban Potable

Rural

Urban Waste Rural Waste Manuf. Waste Manuf. Collected

Rural Collected

Urban Collected

Recycling

11

Table S3: Parameterization of the water supply and wastewater treatment technologies. A range of data is identified from the indicated literature sources. Data labelled ‘Efficient’ is used to parameterize technologies in the SDG6-Efficiency scenario. All other scenarios use mid-range data labelled ‘Baseline’.

Technology / Process Parameter Units Efficient Baseline Source(s)

Thermal Desalination1

Urban / Manufacturing Water Distribution

1. For simplification, thermal desalination technologies are parameterized to represent multi-stage flash and distillation options.

2. Representative of a common septic system. Additional energy requirements are expected to be negligible.

3. For simplification, the same technology is used to represent manufacturing and urban municipal wastewater recycling.

4. Electricity intensities for pumping reflect averages for surface and groundwater systems and do not account for long-distance transfers.

5. Electricity intensities for wastewater pumping are allocated to the treatment and recycling technologies and reflect averages.

12

Figure S16: Water sector costs in 2030 in each MESSAGE region and globally.

(1) (2) (3) (4) (5) (6)

AFR

020406080

(1) (2) (3) (4) (5) (6)

CPA

0100200300

(1) (2) (3) (4) (5) (6)

EEU

05101520

(1) (2) (3) (4) (5) (6)

FSU

020406080

(1) (2) (3) (4) (5) (6)

LAM

050100150

(1) (2) (3) (4) (5) (6)

MEA

050100150

(1) (2) (3) (4) (5) (6)

NAM

050100150

(1) (2) (3) (4) (5) (6)

PAO

01020304050

(1) (2) (3) (4) (5) (6)

PAS

050100150

(1) (2) (3) (4) (5) (6)

SAS

0100200300

(1) (2) (3) (4) (5) (6)

WEU

020406080120

(1) (2) (3) (4) (5) (6)

World

050010001500

Water Infrastructure Storage (excl. Hydro) Pumps & Distribution Wastewater Collection Wastewater Treatment

Wastewater Recycling Desalination Conservation

Water Sector Costs in 2030 [ billion USD per year ]

Infrastructure Transformation Pathway

Infrastructure Transformation Pathway (1) NoWatPol | NoClimPol (2) NoWatPol | 1.5 °C

(3) SDG6−Supply | NoClimPol (4) SDG6−Supply | 1.5 °C

(5) SDG6−Efficiency | NoClimPol (6) SDG6−Efficiency | 1.5 °C

13

Figure S17: Water sector costs in 2070 in each MESSAGE region and globally.

(1) (2) (3) (4) (5) (6)

AFR

050100150200

(1) (2) (3) (4) (5) (6)

CPA

0100200300

(1) (2) (3) (4) (5) (6)

EEU

05101520

(1) (2) (3) (4) (5) (6)

FSU

020406080100

(1) (2) (3) (4) (5) (6)

LAM

050100150200

(1) (2) (3) (4) (5) (6)

MEA

050100150200

(1) (2) (3) (4) (5) (6)

NAM

050100150

(1) (2) (3) (4) (5) (6)

PAO

010203040

(1) (2) (3) (4) (5) (6)

PAS

050100150

(1) (2) (3) (4) (5) (6)

SAS

0100200300400500

(1) (2) (3) (4) (5) (6)

WEU

050100150

(1) (2) (3) (4) (5) (6)

World

0500100015002000

Water Infrastructure Storage (excl. Hydro) Pumps & Distribution Wastewater Collection Wastewater Treatment

Wastewater Recycling Desalination Conservation

Water Sector Costs in 2070 [ billion USD per year ]

Infrastructure Transformation Pathway

Infrastructure Transformation Pathway (1) NoWatPol | NoClimPol (2) NoWatPol | 1.5 °C

(3) SDG6−Supply | NoClimPol (4) SDG6−Supply | 1.5 °C

(5) SDG6−Efficiency | NoClimPol (6) SDG6−Efficiency | 1.5 °C

14

Figure S18: Water supply mixture in 2030 for each MESSAGE region and globally.

(1) (2) (3) (4) (5) (6)

AFR

050100150

(1) (2) (3) (4) (5) (6)

CPA

0200400600800

(1) (2) (3) (4) (5) (6)

EEU

051015202530

(1) (2) (3) (4) (5) (6)

FSU

050100150200

(1) (2) (3) (4) (5) (6)

LAM

050150250350

(1) (2) (3) (4) (5) (6)

MEA

0100200300400

(1) (2) (3) (4) (5) (6)

NAM

0100200300400

(1) (2) (3) (4) (5) (6)

PAO

020406080120

(1) (2) (3) (4) (5) (6)

PAS

0100200300400

(1) (2) (3) (4) (5) (6)

SAS

0200400600800

(1) (2) (3) (4) (5) (6)

WEU

050100150200250

(1) (2) (3) (4) (5) (6)

World

01000200030004000

Water Source Conventional Recycling

Desalination Conservation

Freshwater Supply in 2030 [ km3 per year ]

Infrastructure Transformation Pathway

Infrastructure Transformation Pathway (1) NoWatPol | NoClimPol (2) NoWatPol | 1.5 °C

(3) SDG6−Supply | NoClimPol (4) SDG6−Supply | 1.5 °C

(5) SDG6−Efficiency | NoClimPol (6) SDG6−Efficiency | 1.5 °C

15

Figure S19: Water supply mixture in 2070 for each MESSAGE region and globally.

(1) (2) (3) (4) (5) (6)

AFR

050150250350

(1) (2) (3) (4) (5) (6)

CPA

0200400600

(1) (2) (3) (4) (5) (6)

EEU

05101520

(1) (2) (3) (4) (5) (6)

FSU

050100150200

(1) (2) (3) (4) (5) (6)

LAM

0100200300400

(1) (2) (3) (4) (5) (6)

MEA

0100200300400

(1) (2) (3) (4) (5) (6)

NAM

0100200300

(1) (2) (3) (4) (5) (6)

PAO

020406080100

(1) (2) (3) (4) (5) (6)

PAS

0100200300400

(1) (2) (3) (4) (5) (6)

SAS

02006001000

(1) (2) (3) (4) (5) (6)

WEU

050100150200

(1) (2) (3) (4) (5) (6)

World

01000200030004000

Water Source Conventional Recycling

Desalination Conservation

Freshwater Supply in 2070 [ km3 per year ]

Infrastructure Transformation Pathway

Infrastructure Transformation Pathway (1) NoWatPol | NoClimPol (2) NoWatPol | 1.5 °C

(3) SDG6−Supply | NoClimPol (4) SDG6−Supply | 1.5 °C

(5) SDG6−Efficiency | NoClimPol (6) SDG6−Efficiency | 1.5 °C

16

Figure S20: Power generation mixture in 2030 for each MESSAGE region and globally.

(1) (2) (3) (4) (5) (6) (6) SDG6−Efficiency | 1.5 °C

17

Figure S21: Power generation mixture in 2070 for each MESSAGE region and globally.

(1) (2) (3) (4) (5) (6) (6) SDG6−Efficiency | 1.5 °C

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