Climate Change Impacts in Different
Agro-ecological Zones of West Africa
– Humid Zone
Paper presented at the International Workshop on Adaptation to Climate
Change in West African Agriculture at Ouagadougou, Burkina Faso
from 27 – 30 April 2009
Dr. Anthony C. Anuforom
Permanent Representative of Nigeria with WMO
Nigerian Meteorological Agency (NIMET)
33 Pope Paul II Street
Maitama District,
ABUJA
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development and safety of life and property
Outline of Presentation
•
Introduction – Contemporary Issues on
Change in Africa
•
Humid Zone of West Africa
•
Evidence of Effects of Climate Change in the Humid
Zone of West Africa.
•
Challenges to Adaptation to Climate Change in the
region.
•
Concluding Remarks
Climate
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Introduction – Contemporary Issues on
Climate Change in Africa
High climate variability and drought in West Africa in the 1970s and
1980s had adverse effect on agriculture, particularly in the Sahel.
And, according to IPCC 4th Assessment Report, by 2020….
(i)Between 75 and 250 million people may be exposed to increased water
stress due to climate change and this will adversely affect livelihoods in the
region.
(ii)The area suitable for agriculture, the length of growing seasons
and yield potential, are expected to decrease due to Climate Change.
(iii) Yields from rain-fed agriculture in some countries could be
reduced by up to 50%!
(iv) Africa remains one of the most vulnerable continents to climate
variability and change because of multiple stresses and low adaptive
capacity.
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Introduction – Contemporary Issues on
Climate Change in Africa (contd.)
For the West African sub-region...
(i)Agriculture is critical to the economy. While the world average
contribution of the agriculture sector to the Gross Domestic Product (GDP)
is only 4.5 %, the sector’s contribution is about 30 % in West Africa.
(ii) In addition to the above, over 65 % of the population in the region is
rural, and about 90 % of the rural population directly depends on rain-fed
agriculture for income and food security. Therefore reduction in rainfall
as predicted by various Climate Models translates to threat to
livelihood of the population and the economy of the sub-region.
(iii)The 2005 FAO Global Forest Resources Assessment showed that forest
and woodland in Sub Saharan Africa presently cover about 530 million ha,
compared to 710 million ha in 1975. This ongoing degradation of natural
resources is reducing the resilience of the agro-ecosystems to drought,
further undermining the region’s future capacity to cope with climate
change.
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Introduction
Time series (1941-2001) of average normalized April-October rainfall departure for 20 stations in the West
African Soudano-Sahel zone (11-18N and West of 10E); following methodology of Lamb and Peppler,1992).
Nigerian Meteorological Agency (NIMET) …… providing weather, climate and water information for sustainable
development and safety of life and property
Introduction
Nigerian Meteorological Agency (NIMET) …… providing weather, climate and water information for sustainable
development and safety of life and property
Introduction
Nigerian Meteorological Agency (NIMET) …… providing weather, climate and water information for sustainable
development and safety of life and property
Introduction
Nigerian Meteorological Agency (NIMET) …… providing weather, climate and water information for sustainable
development and safety of life and property
Humid Zone of West Africa
Definition
•
The zone that supports forests as the typical vegetation
cover
•
Zone where annual precipitation exceeds evaporation.
However, this definition encompasses all areas that are not
desert or semi-arid
• Other approaches to delineating the zones include those of
Thornthwaite, 1931, 1948; Griffiths and Driscoft, 1982, Oliver and
Hidore, 2002 as part of general climatic classifications.
Thornthwaite used moisture index to define humid climate as
having positive index values
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development and safety of life and property
Humid Zone of West Africa (contd.)
Some Characteristics of the Zone
•
Consists of forests and forest-savannah transition area.
•
Covers about 10% of the West African region, including
Liberia and parts of Cameroon, Côte d’Ivoire, Ghana,
Guinea, Nigeria, Sierra Leone, and Togo.
•
Receives more than 1,500 millimeters of rainfall
annually and has a growing period of 7 to 12 months.
•
The soils are very acidic and easily degraded without
vegetation cover.
•
The long rainy season in the zone is favorable to roots
crops which contribute significantly the GDP.
•
The zone is less favorable for pastoral agriculture.
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Humid Zone of West Africa
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development and safety of life and property
Humid Zone of West Africa
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Is Climate Change Evident in the Humid
Zone of West Africa?
Late onsets of rains in a few
places
Late Onset now spreading to
many parts of the country
14
14
SOK
KAT
NGU
SOK
BRK
KAT
GUS
KAN
12
DUT
POT
GUS
MAI
DAM
KAN
12
DUT
ZAR
GOM
Latitude (degrees N)
Latitude (degrees N)
BAU
JOS
MIN
JEB
SHK
BID
YOL
ABU
JLG
ILO
LAF
IBI
ISY
8
LOK
OSB
IBA
ABE
MKD
AKU
OND
OTU
ENU
ONT
6
WAR
SHK
8
BID
JLG
LAF
IBI
LOK
OSB
MKD
AKU
OND
OTU
OGJ
IKE
ENU
BEN
ONT
IKM
6
WAR
CAL
PHC
YOL
ABU
ILO
ISY
IBA
ABK
ABK
IKM
OWEUMU
YEN
4
GOM
MIN
JEB
IJB
OWEUMU
YEN
BAU
JOS
10
OGJ
BEN
KAD
KON
ABE
IJB
IKE
MAI
DAM
YEL
KAD
KON
POT
ZAR
YEL
10
NGU
BRK
CAL
PHC
4
2
4
6
8
10
12
14
Longitude (degrees E)
Deviation of 1941 – ’70 Mean
onset date of rainy season from
the 1911 – ’40 onset dates
2
4
6
8
10
12
14
Longitude (degrees E)
Deviation of 1971 – 2000 Mean
onset date of rainy season from the
1911 – ’40 onset dates
Early cessation of the rains
now affect many parts of the
country
Early cessation of rains in
and around Ondo/Ilorin
14
14
SOK
SOK
KAT
GUS
GUS
KAN
12
DUT
POT
DUT
Latitude (degrees N)
Latitude (degrees N)
BAU
GOM
JOS
MIN
JEB
BID
YOL
ABU
JLG
ILO
LAF
IBI
ISY
LOK
OSB
IBA
ABE
MKD
AKU
OND
BAU
MIN
JEB
SHK
BID
YOL
ABU
JLG
ILO
LAF
IBI
8
ISY
LOK
OSB
IBA
MKD
AKU
OND
OTU
IJB
ONT
WAR
ONT
IKM
6
WAR
ABK
IKM
OWEUMU
YEN
CAL
PHC
ENU
BEN
ABK
OWEUMU
YEN
OGJ
IKE
OGJ
ENU
BEN
GOM
JOS
10
ABE
IJB
6
KAD
KON
OTU
IKE
MAI
DAM
YEL
KAD
10
POT
ZAR
ZAR
KON
KAN
12
MAI
DAM
YEL
8
NGU
BRK
BRK
SHK
KAT
NGU
CAL
PHC
4
4
2
4
6
8
10
12
14
Longitude (degrees E)
Deviation of 1941 – ‘70 Mean
cessation date of rainy season
from the 1911 – ’40 cessation
dates
2
4
6
8
10
12
14
Longitude (degrees E)
Deviation of 1971-2000 cessation
dates from 1911-’40
RAINFALL DEPARTURE ANOMALIES FROM 1991 - 2006 OVER
THE WMO REFERENCE PERIOD 1961 - 1990 IN NIGERIA
14
KT
SO
NG
GU
KN
MA
PT
12
ZA
KA
YE
BA
BI
10
JO
MI
AB
AO
ISIK
BD
LA
IL
SH
IS
8
YL
OS
IB
IJ
JA
EB
MK
LO
ON AK
BE
6
OG
EN
AS
OT
WR
IK
OW
AB UY CB
PH
EK
SLIGHT DEFECITS OVER AREAS
SHADED RED AND SURPLUS
OVER GREEN AREAS
14
-2
-1
12
-0.5
0
10
0.5
1
8
1.5
6
2
4
2.5
2
-1.5
4
Climate Change Effects in the Humid Zone
 Late onset of the rainy season spreading to more areas in the





humid zone.
Early cessation of the rains
Shorter rainy season
Shorter cropping season
Water shortages, Drought conditions
Desertification conditions spreading, etc
Resulting to ...
 Changes/shifts in boundaries between agro-ecological
zones and
 Progressive depletion of forest resources of West Africa
 Threat to food production and security.
 Distortion of crop calendar.
 Changes in distribution of animal diseases and parasites.
 Changes in bio-diversity
Climate Change Impacts in the Humid Zone
Livestock
impacts
Changes in forage resources; shifts in forests vegetation
structure or boundaries; changes in forage quality and
quantity; reduction in harvest forage; changes in length of
growing season; reduced feed intake and changes in
livestock productivity such as milk production, growth rates
and weight gain, reproduction; and changes in water quality
and quantity, shift in types of herbivores;
Ecological
impacts
Alteration in carbon storage capacity of the ecosystem;
alterations in greenhouse gas emissions; disturbances in
ecosystem functions (e. g. alteration in biogeochemical
cycling, incidence of wild fires etc.); changes in soil quality
and productivity; changes in biodiversity and changes in
habitat suitability for wildfire
Socioeconomic
impacts
Changes in food production and security (locally and
nationally; changes to incomes derived from livestock
production, wildlife, and other forest outputs; changes in
land use; changes in recreational use of forests and
alteration in scenic quality
Nigerian Meteorological Agency (NIMET) …… providing weather, climate and water information for sustainable
development and safety of life and property
Challenges to Adaptation to Climate Change in
Humid Zone of West Africa
•
Although empirical data (particularly rainfall) indicate shifts in rainfall
characteristics in parts of West African Humid Zone, the subject is not yet fully
understood.
•
NHMSs in the sub-region have key roles to play in providing meteorological
information for decision-making and for planning adaptation and mitigation
strategies. Unfortunately however, some of these NHMSs are relatively weak in
terms of observational infrastructure and manpower.
•
There is therefore need for capacity building in climate change observation and
analyses with a view to identifying climate risks and generating knowledge and
managing climate change risks in agriculture, health, water resources, forestry,
etc.
•
Meteorological services and products, such as seasonal rainfall predictions and
other early warning information, are largely not understood by rural farmers
who form the bulk of the workforce in agriculture.
•
Although over time, local farmers have evolved indigenous adaptation and
mitigation strategies, it is necessary to blend and re-enforce these with
scientific knowledge.
Nigerian Meteorological Agency (NIMET) …… providing weather, climate and water information for sustainable
development and safety of life and property
Conclusion
•
The droughts that occurred in West Africa in the 1970s and 1980s had adverse
impact on agriculture and hence the economies of countries in the sub-region
Africa, particularly the Sahel.
•
IPCC 4th Assessment Report indicates that the area suitable for agriculture, the length
of growing seasons and yield potential in Africa, are expected to decrease due to Climate
Change. Africa remains one of the most vulnerable continents to climate variability and
change because of multiple stresses and low adaptive capacity.
•
Up to 10% of West Africa falls within the humid zone. The zone is characterized by high rainfall and forest
cover is the typical vegetation.
•
Empirical evidence indicates significant change in the rainfall pattern in the humid zone. However, there
is inadequate understanding of how climate change will affect West Africa in the
coming decades. More research is therefore required to understand how West
African agro-ecosystems will respond to climate change; how livelihoods will be
affected, with a view to evolving the necessary adaptation and mitigation
strategies.
•
Capacity-building is required to enable NHMSs in the West African sub-region play
the expected role of providing meteorological products and services for climate
change adaptation and mitigation.
Nigerian Meteorological Agency (NIMET) …… providing weather, climate and water information for sustainable
development and safety of life and property
Thank You
for Listening
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development and safety of life and property