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