1 Presented by: Ms. Fatou SIMA Meteorologist Dept. of Water Resources 7, Marina Parade, Banjul Tel: 4377098/7990855 Email: [email protected].

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Presented by: Ms. Fatou SIMAMeteorologist

Dept. of Water Resources7, Marina Parade, Banjul

Tel: 4377098/7990855Email: [email protected]

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Introduction

Objective

Methodology & Tools

Climate Change Scenarios

Observed Impacts of C_Change

Conclusions & Recommendations

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• There is increasing concern over climate change phenomena all

over the world. Both developing and developed countries have

accepted that urgent and definite actions need to be taken to

reverse the effects of mans misuse of the natural resources.

• There is also substantial evidence from the IPCC assessment of climate from the pre- industrial period to the present that the climate is changing over most of the regions. Source; Nigeria climate review bulletin, 2007

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What is Climate Change?• C_Change is a statistically significant variation in either the meant state of the climate or its variability, persisting for an extended period of decades or longer.

What causes Climate Change?• natural internal processes/,

• by persistent anthropogenic (man-made) changes in the composition of the atmosphere or in landuse.

Figure 1

Figure 2

Figure 3

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• The objective of this presentation is to provide climate scenario information advice to decision makers and to ensure that the resulting impacts can be used to provide Gambians with a meaningful national assessment of the impacts of C_Change and how it can contribute to future assessments.

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The main steps were:

Method;

• Collection of Meteorological data;

• Statistical calculation of the long-term data for the Baseline climate scenarios of The Gambia;

• Comparison of model performance with the current data.

Tools;

• Magic (Scengen); develop the model performance,

• INSTAT+; calculate the key factors of the growing season,

• Surfer is used for mapping,

• Excel for some agro- climatic analysis.

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The climate community uses 2 types of scenarios for the study of climate variability and change.

• Baseline scenarios estimate how the world would change without climate change.

• Climate change scenarios, on the other hand, estimate likely changes in the climate system that are caused by a certain forcing agent such as increase in concentration of CO2 in the atmosphere.

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Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Ann.Avg

Mean Temperature (0C)1951-2005 24.9 26.7 28.4 29.5 30.1 29.7 28.2 27.6 27.7 28.5 27.4 25.3 27.8

Min Temperature (0C)1951-2005 16.1 18.4 21.3 23.9 25.6 25.1 23.9 23.4 23.0 23.2 19.0 16.0 21.6

Max Temperature (0C)1951-2005 33.9 36.1 37.9 38.6 38.1 35.8 32.8 31.8 32.3 34.0 35.4 34.1 35.1

Rainfall (mm)1951-2005 0.34 0.37 0.03 0.13 7.44 77.06 202.62 290.53 212.51 65.06 3.30 0.53 859.90

Relative Humidity (%)1951-2005 38 36 38 42 50 63 75 80 80 75 58 44 57

Wind (knots)1951-2005 5 5 5 5 5 5 4 4 3 3 3 4 4

Solar Radiation (L/day)1971-1984 492 597 625 624 607 550 483 481 503 545 516 461 541

Solar Radiation (Joules)1972-2002 4539 5433 5781 6132 6004 5180 4704 4648 4973 4868 4351 4185 5067

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Figure 4. Model Projections for monthly mean temperatures (0C) for The Gambia to 2100

10.0

15.0

20.0

25.0

30.0

35.0

40.0

JAN

FE

B

MA

R

AP

R

MA

Y

JUN

JUL

AU

G

SE

PT

OC

T

NO

V

DE

C

Tem

per

atu

res

(0 C)

1951 - 2005 BMRC 98 CCC199

GFDL90 HAD295 HAD300

Except for the BMRC Model other models show that warming of the atmosphere will be almost the same as current climate. The BMRC model shows that temperatures will increase by about 5oC above current climate.

10

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

2010 2020 2030 2040 2050 2060 2070 2075 2080 2090 2100

CCCM

BMRC98

GFDL90

Figure 5. Model Projections for annual mean temperatures (0C) for The Gambia to 2100

All the 3 models used in the Study show increase in temperature of about 0.5 in 2010 to about 3.0 to 4.0oC by 2100. The BMRC Model shows the largest increase of about 40C.

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Figure 6. Model Projections for annual mean Rainfall (mm) for The Gambia to 2100

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

2010 2020 2030 2040 2050 2060 2070 2075 2080 2090 2100

BMRC98

CCCM

GFDL90

Again the BMRC shows the largest increase in rainfall varying from about 1% increase in 2010 to about 12% increase by 2100. The other models show increase of about 0% in 2010 to about 2.2% by 2100.

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E.g ;• Interannual Variability of Rainfall • Unseasonal rainfall • Flooding• Key factors of the rainy season (onsets,

cessations & S_lengths)

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Figure 7: Annual total rainfall (mm) for Banjul from 1886 - 2007

40.00

340.00

640.00

940.00

1240.00

1540.00

1840.00

1886

1892

1898

1904

1910

1916

1922

1928

1934

1940

1946

1952

1958

1964

1970

1976

1982

1988

1994

2000

2005

Rain

fall

(mm

)

Figure 8: Annual total rainfall (mm) for Yundum Airport from 1946 - 2007

300.00

600.00

900.00

1200.00

1500.00

1800.00

2100.00

Rai

nfal

l (m

m)

Figure 9: Annual total rainfall (mm) for GeorgeTown/Janjanbureh from 1908 - 2007

400.00

600.00

800.00

1000.00

1200.00

1400.00

1908

1913

1918

1923

1928

1933

1938

1943

1948

1953

1958

1963

1968

1973

1978

1983

1988

1993

1998

2003

Rainf

all (m

m)

Figure 10: Annual total rainfall (mm) for Basse from 1942 - 2007

400.00

600.00

800.00

1000.00

1200.00

1400.00

1600.00

1800.00

1942

1946

1950

1954

1958

1962

1966

1970

1974

1978

1982

1986

1990

1994

1998

2002

2006

Rai

nfal

l (m

m)

Interannual Variations of the Annual total rainfall (mm)

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Figure 11: Annual total rainfall (mm) for Kuntaur from 1945- 2007

300.00

600.00

900.00

1200.00

1500.00

1800.00

1945

1948

1951

1954

1957

1960

1963

1966

1969

1972

1975

1978

1981

1984

1987

1990

1993

1996

1999

2002

2005

Rai

nfa

ll (m

m)

Figure 12: Annual total rainfall (mm) for Kerewan 1926 - 2007

300.00

600.00

900.00

1200.00

1500.00

1800.00

2100.00

1926

1930

1934

1938

1942

1946

1950

1954

1958

1962

1966

1970

1974

1978

1982

1986

1990

1994

1998

2002

2006

Rai

nfal

l (m

m)

Interannual Variations of the Annual total rainfall (mm)

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-17 -16.5 -16 -15.5 -15 -14.5 -1413

13.5 B anju l

B asse

Fato to

G eorgetow nJeno i

K aur

K erew an

K untaur

Y undum A irport

S ibanor

0 150 300 450

2.99

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

Jan Feb Mar April Nov Dec

Rain

fall

(m

illi

metr

es)

Figure 14. Annual total unseasonal rainfall (mm) for the period 1951- 2007 (57yrs) for The Gambia

Figure 13. Monthly average unseasonal rainfall (mm) for the period 1951 –2007 (57yrs.) for The Gambia

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Figure 16. Flood victimsFigure 15. Effects of flood at Ebo Town in 2007

Flooding is one of the most damaging natural disasters; victims were subjected to food insecurity, decline in crop productivity, and pollution of water supply, favorable conditions for breeding mosquitoes. In 2007, residents of parts of Ebo Town are in tears crying out for immediate assistance due to the flood that has wreaked havoc on poor inhabitants recently.

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37

27

0

5

10

15

20

25

30

35

40

Bar

ra

May

amb

a

Sam

Ko

to

Sam

i K

uta

Ban

tan

din

g

Dar

u

Ker

ewan

Nja

war

a

Naw

teru

Ind

ia

Jum

ansa

rr

Yal

lal

Far

afen

ni

Nb

app

u B

a

Jum

an

Dar

u

Ku

nja

fa

Bo

llo

Eb

ra

Ko

nte

h

Sab

ach

jaja

ri

No

. o

f h

ou

ses

des

tro

yed

Figure 17. Houses destroyed by heavy intensity of rain at the NBR for the period 2004

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• Climatic events based on long-term meteorological data show discernible evidence of C_Change in the country.

• This statement is supported by the analysis of variability’s of long- term (1961-1990) & (1971-2000) on dates of onset, cessation, & season lengths of rainfall occurrence for selected stations in The Gambia using criteria;

- After 1st May, rainfall amounting 20mm in 1 or 2 consecutive days not followed by a dry spell of 10 days in next 30 days of sowing (Alimi et al., 1992).

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-17 -16.5 -16 -15.5 -15 -14.5 -1413

13.5Y undum

K erew an Jeno i

K aur

B asse

Jan jangbureh

K untaur

B an ju l Fa to to

S ibanor

B ansang

166 171 176 181

Normal onset Early onsetLate onset

1961-1990

-17 -16.5 -16 -15.5 -15 -14.5 -1413

13.5Y undum

K erew an Jeno i

K aur

B asse

Jan jangbureh

K untaur

B an ju l Fa to to

S ibanor

B ansang

169 173 177 181 185 1971-2000

Early onset

Normal onset

Late onset

Fig. 18a. 1961 – 1990, only the Western sector of the country experiences late onsets

Fig. 18b: However, as the years progressed (1971 – 2000) the late onset had spread to more areas

Onsets:

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-17 -16.5 -16 -15.5 -15 -14.5 -1413

13.5Y undum

K erew an Jeno i

K aur

B asse

Jan jangbureh

K untaur

B an ju l Fa to to

S ibanor

B ansang

291 294 297 300

-17 -16.5 -16 -15.5 -15 -14.5 -1413

13.5Yundum

Kerewan Jenoi

Kaur

Basse

Janjangbureh

Kuntaur

Banju l Fatoto

S ibanor

Bansang

291 293 295 297

Fig. 19a: 1961 – 1990, few areas of the country experienced early cessation of the rains

Fig. 19b: However, 1971 – 2000, early cessation (red) has spread to more areas of the country

Normal Cessation

Normal Cessation Late Cessation

Late Cessation

1961-1990

1971-2000

Cessation:

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-17 -16.5 -16 -15.5 -15 -14.5 -1413

13.5Yundum

Kerew an Jeno i

Kaur

Basse

Jan jangbureh

Kuntaur

Banju l Fato to

S ibanor

Bansang

110 114 118 122 126 130 134

-17 -16.5 -16 -15.5 -15 -14.5 -1413

13.5Yundum

Kerew an Jeno i

Kaur

Basse

Jan jangbureh

Kuntaur

Banju l Fato to

S ibanor

Bansang

1 1 1 1 1 4 1 1 7 1 2 0 1 2 3 1 2 6

Longer S_L

Longer S_LShorter S_L

Normal S_L

Shorter S_L

Normal S_L

1961-1990

1971-2000

Fig. 20a: 1961-1990 , Western & CRR north experiences shorter season lengths.

Fig. 20b: 1971-2000, decreased has spread to more places

S_Lengths:

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Comments;

• Based from this analysis; for 1961 – 1990, most parts of The Gambia had normal onsets and normal cessation dates of rainy season.

•As the years progressed (1971 – 2000) the late onset and early cessation had spread to more areas

•the results of the analysis produces mean season lengths which can be used for choice of crop variety; Mean Season Length (days) 1961-1990 1971-2000 Banjul 114 111 Yundum 116 114 Janjanbureh 126 119 Basse 134 128 Jenoi 119 118 Kerewan 117 117 Kuntaur 115 120Advises;

•Crops with cycle of 120 days should be sown in Basse and environs in the eastern sector.

•Crops with cycle of about 119 days or less should be sown in areas around Banjul, Yundum, Kerewan, Jenoi, Kuntaur and Janjanbureh.  

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• Little or no research has been done in The Gambia on the linkages btw climate and biophysical processes, adverse effects operating indirectly through soil (salinisation, erosion) and water quality degradation (pollution/sediment load, salinity & etc), (NAPA on Climate Change, Banjul

November , 2007).

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•Need to strengthen weather, climate & water monitoring & prediction institutions in order to generate the required data, processed into use-able information, responsive (national development process) to the concerns of various stakeholders,

•Therefore, in order to produce quality data, maximum support is

needed so that our Meteorological stations can be well equipped

with standard equipments.

•Establish partnerships between national weather service and operators in various socio-economic sectors sensitive to variations in the climate system.

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