The document summarizes key drivers of increasing global water demand and potential solutions to close the growing water gap. By 2050, world water demand is projected to increase by 60% due to factors like population growth, changing diets, increased food production and urbanization. Agriculture currently accounts for 70% of water withdrawals globally. Solutions discussed to help close the growing gap between supply and demand include increased wastewater reuse, further development of desalination technologies, improving irrigation efficiency, appropriate water pricing, integrated water governance and planning at the basin scale.

1. WATER
CRISIS?
Julio Berbel
Universidad de CórdobaAlmería, 4 oct. 2018

2. DRIVERS OF
WATER
DEMAND
[1]

3. WATER CYCLE, WATER USE
World water
demand grows
800% last century
IAASTD 2012 Agriculture at a Crossroads: The Global Report. Island Press FAO . Aqustat
Municipal
Industry
Agriculture
1900-2010

4. WATER USE 2050
Source: Agriculture: FAO “optimist scenario”; OECD rest of sectors
Under the Baseline, the number of people living in river basins
under severe water stress is projected to more than double
between 2000 -2050 , reaching 3.9 billion people
0
5,000
10,000
2010 2015 2020 2025 2030 2035 2040 2045 2050
World water use by sector
2010-2050
Agriculture * Manufacturing Electricity Domestic
Domestic
Energy
Indust
Agric
World water
demand for 2050
will grows ≈ 60%

5. DRIVER 1: FOOD PRODUCTION
Population
Diets
2015
2030
2050
1 2 3
Food production
+50
+100%
Nachtergaele et al (2011). Anticipated trends in the use of global land and water resources. FAO. Rome
IAASTD 2012 Agriculture at a Crossroads: The Global Report. Island Press
• Global food supply from rain-fed
areas declines from 65% (2015) to
48% (2030).
• Agriculture uses 70% of total water
withdrawal and accounts for 86% of
consumption.
• Scenarios of water diversions to
agriculture growth are in range [5
to 57%] by 2050

6. HOW TO DUPLICATE FOOD PRODUCTION?
+37%
Fischer & Connor, 2018
FAO World agriculture towards 2030/2050: the 2012 revision
1960-2018 ≈ +1% anual
2018-2050 =
Arable land ≈ + 4%
+4% = 48%
Gap=52%
BAU =48%
??

7. DRIVERS 2: NON-IRRIGATION
 GDP annual rate of growth ≈ 3%
 Energy supply increase +163%
 From 54% (2010) to 66% (2050)
Schlosser, C.A. et (2014) Joint Program Report Series, World Energy Council (2013) World Energy Scenarios: Composing energy futures to 2050; UN (2014)
Population world urbanization prospects 2014
+3%
annual
GDP

8. WATER DEMAND 2010 - 2050
Food
Energy
Households
Industrial
+100%
+63%
∆Urban:+12%
∆GDP: +160%
+130%
GDP
Sector growth
2010 to 2050
Water use
growth
Source: OECD Environmental Outlook (Irrigation data from FAO), Water stress UN
+5 to 57%
+400%
+130%
140%
∆ water use 60%
2050?
Quantity
5 billion will live in
water-stressed
regions
700 million people
suffer from water
scarcity

9. THE FUTURE IS
TODAY
[2]

10. (GROUND)WATER OVEREXPLOITATION
 9% of food comes from overexploted aquifers
 20% of aquifers are overexployted
Green water
47%Blue water
44%
Non renew
9%
Agric gross water use: 2540
km3
Green water Blue water Non renew
Groundwater stress
Wada et al (2012) “Nonsustainable groundwater sustaining
irrigation: A global assessment.” Water Resources Research.

11. URBAN WATER CRISIS (E.G. CAPE TOWN)
 The period from 2015-2017 has been
the driest 3-year period since 1933
(Model found that 1 in 400 year event)
 Cape Town particularly has grown by
50 percent in the last decade
 Provinces don’t have the power to
make water allocations to agriculture.
This is done by the national
government, and 40% of water went to
farming (2015/16)

12. WATER STRESSED REGIONS
52 percent of the world’s
projected 9.7 billion
people will live in water-
stressed regions by 2050
(IGSM-WRS) MIT

13. WATER POLLUTION
UN (2017) “…by 2050
1.4 billion people are
projected to be still
without access to basic
sanitation.”
WWAP (UN World Water Assessment Programme). 2017. The UN World Water Development Report 2017. Wastewater: The
Untapped Resource. Paris, UNESCO.

14. GOOD NEWS:
WATER WITHDRAWAL IS NOT WATER CONSUMPTION
Return flows vs withdrawal
 Agriculture 40%
 Energy (cooling et al) 95%
 Urban, manufacturing80%
FAO (2017)Economic valuation of water resources in agriculture
EC (2012) Blueprint for water
4524 km3 2140 km3
2050 vs 2010
Withdrawal + 51%
Consumption + 22%
2010

15. WHERE IS THE
WATER WE
NEED?
[3]

16. CLOSING THE WATER GAP
How we are (2010)?
Wastewater reuse
Desalination
Water saving?
Water pricing?
Allocation
Governance
20% wastewater is treated
Future ? (2050)
Some regions (ISR, ESP)
recycle 70-90% WW today
Unit cost has reduced 10 fold
since 1960
Cost will arrive to ≈ 0.40
€/m3
Return flows are reused at basin
=> No real savings
Inelastic demand (urban, high
value crops..). Small savings.
Allocation based on historical
rights and ‘rent seeking
behaviour’
Failures, (e.g Cape town), …
Water value & productivity
growth (but no real savings)
Water price as a tool for
financing & equity goals
Water banks, market, water
pricing, planning…
Up-down and user-group
integrated policy, water
accounts

17. SOURCE 1: WASTEWATER: THE UNTAPPED RESOURCE
But the reuse of water need…
 Avoid pollution
 Proper WWT
 Quality reused water assurance
Treatment of the wastewater, by country:
• High-income… 70%
• EU ……… 95%.
• Low-income… 8%
• GLOBALLY… 20%
Waste water reuse destination (market share)
WWAP (UN World Water Assessment Programme). 2017. The UN World Water
Development Report 2017. Wastewater: The Untapped Resource. Paris, UNESCO.

18. SOURCE 2: DESALINATION
Gao, et al (2017). An economic assessment of the global
potential for seawater desalination to 2050. Water, 9(10), 763.

19. SOURCE 3: EFFICIENCY GAINS? (1/2)
MYTHS AND TRUES OF EFFICIENCY GAINS
 Myth 1: Large quantities of
water can be saved by more
efficient irrigation.
 Myth 2: Water demand will fall
as irrigation efficiency and
water productivity improve.
 Truth 1: More “efficient”
irrigation typically increases local
water consumption.
 Truth 2: Water value increases
and water demand becomes less
elastic as irrigation efficiency and
productivity improve.
Adapted from Perry, C (2018) “Improving irrigation management in conditions of scarcity: Myth vs Truth” Global Water Forum. 22 May.
Lecina et al (2011) Ahorro de agua y modernización de regadíos.

20. SOURCE 3: EFFICIENCY GAINS? YES, WE NEED IT (2/2)
Efficiency gains at farm/city level may have not quantitative impact relevant as return flow are
used downstream and local savings are not translated to basin savings…
Indicator 106
EUR
Annual Equivalent Cost (AEC) 114,2
CO2 emissions cost 3,20
Total cost 117,4
Increase of water productivity 148,8
325,6
406,1
Increase of employment 44,5
Increased water supply guarantee 132,3
Increase of tree crop area (CO2 capture) 78,9
80,5Decrease of fertilizer applied per ha 0,5
Diffuse water pollution reduction 1,1
Cost
Direct benefits
CBA = 3,5
When multipliers
indirect effects are
included CBA = 4,3
Guadalquivir RB modernzation 2005-2015 (*)
(*)Borrego, Berbel (2019) Cost-benefit analysis of irrigation modernization in Guadalquivir River Basin. AGWAT

21. SOURCE 4: WATER PRICING .. WORKS? (1/2)
Typical domestic
elasticity
EU ≈ 0.20
Urban
Water demand curves by technique
Irrigation
Fraiture, C., & Perry, C. (2002, June). Why is irrigation water demand inelastic at low price ranges.; EEA
(2017). Water management in Europe: price and non-price approaches to water conservation ; Berbel,
J., & Mateos, L. (2014). Does investment in irrigation technology necessarily generate rebound effects?
Agricultural Systems, 128, 25-34.
Myth 3: Pricing alone can fix water overconsumption issues.
Truth 3: Quotas will inevitably be required to ensure that
demand is constrained to sustainable levels

22. SOURCE 4: WATER PRICING? YES, WE NEED IT (2/2)
EEA (2017)
OECD (2017)
In some of the EU case studies, price does not appear to be a significant
determinant of water demand.
However….water pricing still remains a key instrument in achieving cost
recovery for water services to ensure the maintenance and financing
of existing and future water infrastructure
Consider the following four principles for financing water resources
management:
• Polluter Pays,
• Beneficiary Pays,
• Equity and
• Coherence between policies

23. SOURCE 5:
GOVERNANCE
 Long term planning
 Basin scale
 Water grid (continental)
 Integrated agricultural, urban,
energy and water policy
 Innovation
 Water markets
 Financing investments and
maintenance
 … we know it already… ?

24. FINAL
COMMENT
(Thank you)