Post on 07-Jun-2015
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David MoldenInternational Water Management Institute
Climate Change and Agriculture: Building Resilience Through Better
Water Management in Southern Africa
One liter of water produces one calorie on average
Food
Sup
ply in Calories
One liter of water produces one calorie on average
Diets and water
Between 2,000 and 5,000 liters per person per day –
depending on type and amount of food
eaten and how it is produced
Other Water Pressures
Urbanization
‐
Cities are projected to use 150% more water in 2025
Land Degradation
–
limits further productivity increases
Climate Change –
Shifting patterns of water availability –
potential yields decline in Africa
Energy –
Production and use by agriculture is in competition with hydropower
Drivers of Water Use
How can water be developed and managed to end poverty and hunger?
A question posed to 700 researchers and
practitioners who put together the
Comprehensive Assessment of Water
Management in Agriculture.
Investing in Irrigation
Irrigated Area
Food price index
World Bank lending for irrigation
2.5
2.0
1.5
1.0
0.5
01960 1965 1970 1975 1980 1985 1990 1995 2000 2005
320
280
240
200
160
120
80
40
0
Living Planet Index Freshwater Species
Africa Irrigation
• River basins closed –
Colorado, Murray Darling, Yellow, Indus, Amu Darya, Orange ‐
no additional
water left
• Groundwater overdraft –
in agricultural breadbaskets
• Fisheries – ocean and freshwater at a limit, aquaculture will become more prevalent
• Livestock –
limit on extent of grazing land, more will come from mixed and industrialized production
Limits –
reached or breached
Water Scarcity 2000
1/3 of the world’s population live in basins that have to deal with water scarcity
WHAT OF THE FUTURE?
USA
projectionsdata
20031961 2050
China
India
140
20
120
100
40
60
80
WorldMea
t co
nsum
ptio
n kg
/cap
/yr
Per Capita Meat Demand (kg/cap/yr)
Southern Africa
How much more cereals?
Food demand doubles over the next 50 years because of diet and population growth
Water Needs (ET) will double – without water productivity gains
Climate Change
Mitigation is about gases.
Adaptation is about water.
Climate Change in Africa According to IPCC (2007)
Temperature and precipitation changes over Africa from the MMD‐A1B simulations. Top
row: Annual mean, DJF and JJA temperature change between 1980 to
1999 and 2080 to
2099, averaged over 21 models. Lower row: fractional change in precipitation.
Variability in Precipitation
Thornton et al 2006
likely to increase with climate change
Observed Trends in River Flow
mean daily flow (annual averages) in Niamey (Niger)
0
200
400
600
800
1000
1200
1400
1600
1929
1933
1937
1941
1945
1949
1953
1957
1961
1965
1969
1973
1977
1981
1985
1989
year
[m3/
s]
Rainfall and GDP growthin Ethiopia and in SSA
Impact of rainfall variability on GDP and Agricultural GDP growth
-80
-60
-40
-20
0
20
40
60
80
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
year
%
-30-25-20
-15-10-50510
152025
rainfall variabilityGDP growthAg GDP growth
-6
-4
-2
0
2
4
6
8
10
12
1970
1975
1980
1985
1990
1995
2000
Annual growth rate
(%)
ag grow th GDP grow th
SSA GDP depends on agriculture
Unmitigated Rainfall and Hydrological Variability Impacts Economic Growth and Stability
Water storage mitigates variability
Source: World Bank data from ICOLD
But need to re‐ think water
storage: role of groundwater and
soil moisture.
And beyond: insurance, local
trade
Cub
ic m
eter
s pe
r cap
ita
Water Storage Mitigates Climate Variability
4 43
746 12
87
1406 24
86 3255
4729
6150
01,0002,0003,0004,0005,0006,0007,000
Ken
ya
Eth
iopi
aS
outh
Afri
caTh
aila
nd
Laos
Chi
na
Bra
zil
Aus
tralia
Nor
thA
mer
ica
Cuvelai
Kunene
Zambezi
Limpopo
PunguéBuziSave-Runde
Orange Maputo
Incomati
Umbeluzi
Okavango/Makgadikgadi
Congo
Nile
Lake Chad
NamibiaBotswana
SouthAfrica
Congo (DRC)
Tanzania
Zambia
Zimbabwe
Lesotho
Swaziland
Malawi
Mozambique
Angola
250 5000
Kilometres
N
Rovuma
Thukela
South Africa (#11) and Zimbabwe (#20) are listed amongst the top twenty
countries in the world in terms of the numbers of
dams built (WCD 2000)
Sources: AQUASTAT Database (FAO, 2005); WCD, 2000
Large Dams in Southern Africa
N.B. Large dam: Wall height > 15 m and/or Volume > 2 million m3
(ICOLD, 1999)
• Africa has a total of 1,269 large dams; 827 (65%) of these are in the SADC countries
• SADC dams hold 37% of Africa’s impounded water
• South Africa (#11) and Zimbabwe (#20) are listed amongst the top twenty countries in the world in terms of the numbers of dams built
Policy Agenda –Where is there hope?
Around 70% of the world’s under‐
nourished live in rural areas where non‐agricultural
livelihood options are limited.
Get water to poor people, use it better
Improve and Safeguard Water Access
Access to Technologies
Consider A Range of Agricultural Water Management Options
Fish, Livestock, Crops, Ecosystem Services
A range of options Water sources in Krishna basin
Krishna river basin
24 major reservoirs
6100 small reservoirs
High groundwater use
Adapt yesterday’s irrigation to tomorrow’s needs
1. To reduce rural poverty
2. To improve performance of many systems,
3. To keep up with changing food demand
4. To adapt to changes – water scarcity,
competition, climate change, energy5.
To increase multiple benefits and ecosystem
services, while reducing negative impacts
Manage Water in Rainfed Landscapes
• Even if area irrigated doubles, the contribution to food production for SSA from irrigation would
change from 5 to 11%• Rainfed areas, especially in the semi‐arid tropics,
have the highest potential for poverty reduction and water productivity gains.
Upgrade Water Management in Rainfed Landscapes
The Small Reservoirs Project
Small Reservoirs
…. Half-moon with millet crop… Newly prepared half-moon at the inception of rain
…. Tied- ridges
Increase Water Productivity• Physical Water Productivity – more crop per
drop– To reduce future water needs– For food production increases
• Economic Water Productivity – more value per drop
– For more income, growth
– Integrated, multiple use systems
Productivity
United States
China
Latin
America
Sub‐Saharan
AfricaM
aize yield (tons/hectare)
Importance of Fish and Livestock for Economic Water Productivity
Make difficult choices now, not later;
Try to increase the pie – share the benefits
But difficult choices remain:
• Water storage for agriculture – water for environment
• Upstream – Downstream
• Productivity ‐
Equity
• This generation – the next one (GW decline)
Reform the policy reform process
• Poverty, hunger, gender inequality, and ecosystem degradation continue
‐
not because of technical failings but because of political and institutional
failings
Africa’s diversity is it’s wealth: • Diversity is a key to resilience• No blueprints ‐
need to craft local
solutions
Thank You !
“Anyone who can solve the problems of water will be worthy of two Nobel Prizes – one for peace and one for science”
John F Kennedy