Download - Water and Climate Change in Africa
Water and Climate Change in Africa
Raffaello CervigniThe World Bank
Key Messages
1. The present: water management is a major constraint to Africa’s development
2. The future: climate change will make those constraint even more severe
3. The opportunity: climate change will increase the urgency of reforms and investments that would be important anyway
4. The challenge: we need both more knowledge, and more resources
The present
Challenging natural conditions
Risk of recurrent Risk of recurrent droughtdrought
Median rainfall and standard deviation USA - SSA
0
200
400
600
800
1000
1200
0 20 40 60 80 100
median rainfall %
stan
dar
d d
evia
tio
n
SSA
USA
High variability and low quantities for much of the continent
Frequent extreme weather events
Hydrological variability has huge impacts on poverty & livelihoods
Correlation between Rainfall and Real GDP growth in Zimbabwe
-10.0
-5.0
0.0
5.0
10.0
15.0
20.0
25.0
Years
-4.0
-3.0
-2.0
-1.0
0.0
1.0
2.0
3.0
4.0
Real GDP growth (%)
Variability in Rainfall (Meter)
Relationship holds even in diverse middle income economies with substantial water storage infrastructure e.g. Morocco
Inability to smooth water availability has multi-sectoral implications
• Under present conditions (water storage, agricultural development, transport infrastructure etc), hydrologic variability reduces potential economic growth in Ethiopia by 38% and increases poverty by 25%
• A single drought over a 12-year period will decrease average GDP growth rates by 7-10%
Countries across continent already facing different kinds of water crisis
Proportion of Total Freshwater Resources Stored in Reservoirs
0
10
20
30
40
50
60
70
80
90
EAPECA
LAC
MNA
SASSSA
North A
mer
ica
Aus/N
Z
W. E
urop
e
Under-use in SSA, limited margins in North Africa
Water storage south of the Sahara is woefully under-developed
11
47
114 13
9
142
307 36
3
370
492
788
0
100
200
300
400
500
600
700
800
900Le
soth
o
Eth
iopi
a
Ken
ya
Alg
eria
Tan
zani
a
Nig
eria
Nam
ibia
Bur
kina
Fas
o
Mor
occo
Sou
th A
fric
a
sto
rag
e / c
apit
a
Water management in Africa is particularly challenging, because international river basins are predominant
The future
What is expected to change?
• Temperature:– Expected to increase 2°- 6°C (over next
century) with greatest impact over the semi-arid margins of the Sahara and central southern Africa and least in equatorial latitudes and coastal environments.
• Precipitation:– Projected future changes in mean seasonal
rainfall in Africa are less well defined.
Severe, but diverse impactsPercent change in run-off: multi-model average for the winter and summer precipitation (A1B SRES scenario)
Reduction of 20 to 30% by 2050
Source: Milly et al (2005), published in Nature
Increaseof 20 to 30%
by 2050
In water-scarce countries, agriculture will change
• Rain-fed agriculture will become less reliable • Water allocations to agriculture will fall significantly
– Urban use will take priority and urban populations growing
• New irrigation schemes will have to be designed for lower water availability
• Less surface water will encourage users to use groundwater
• Controlling this is a highly complex institutional challenge
• Reduced water availability in agriculture increases dependence on trade (high value crops for export, import of staples)
The opportunity
When countries can smooth consumption, agriculture becomes much more stable
-30
-20
-10
0
10
20
30
40
1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002
Year
Ag
ricu
ltu
re, v
alu
e ad
ded
(A
nn
ual
% g
row
th)
Ethiopia
Egypt
Sudan
• Improved monitoring, assessment of water balance
• Improved planning and allocation processes, including internationally
• Strengthening institutions to manage water
• Investments
Actions needed will become all the more important
There will be no substitute for reform
• It will become all the more important to review – Policies that promote
activities that are particularly vulnerable to precipitation
• E.g. subsidies for rainfed wheat production in North Africa
– Plans for new infrastructure where institutions are not yet ready to generate the potential benefits
The challenge
Improving knowledge for better planning
Change in rainfall(mm/year)
200100
0-100-200
CCSR2040-2069
NCAR2010-2049
GFDL2010-2049
CGCM12040-2069
CSIRO2040-2069
HADCM22040-2069
ECHAM42040-2069
Mobilizing resources for storage management
Years needed at 10% current GDP investment per year to reach South Africa Standard
0 10 20 30 40 50 60 70 80
Morocco
Algeria
Namibia
Burkina Faso
Kenya
Nigeria
Senegal
Lesotho
Uganda
Tanzania
Ghana
Ethiopia
Climate change can be an opportunity
• The door may be opening, provided . . . .
• Political attention internationally
• Consensus at national and local level