Transcript PRESENT AND FUTURE CLIMATE SCENARIOS OF SIERRA LEONE

PRESENT AND FUTURE CLIMATE
SCENARIOS OF SIERRA LEONE

REPORT ON THE DEVELOPMENT OF PRESENT
AND CLIMATE CHANGE SCENARIOS OF SIERRA
LEONE FOR USE IN THE ASSESSMENT OF
VULNERABILITY OF SIERRA LEONE TO THE
PROJECTED CLIMATE CHANGE IN SIERR LEONE
SECOND COMMUNICATION WITH THE UNFCCC
Contents and order of Presentation
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PURPOSE AND SCOPE OF THE STUDY
Needs of inter-disciplinary Assessment expert Teams
Present Country Climate Situation
COUNTRY CLIMATE CHANGE SCENARIOS UP TO 2125
Temperature Scenarios
Precipitation Scenarios
Evaporation
Solar Radiation
CO2 levels and Sea Level Rise Scenarios
Conclusions and Recommendations
PURPOSE AND SCOPE OF THE
STUDY
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The current assessment uses the previous finding as our base
line. The present study therefore builds on this to close some
of the gaps that were left out by the initial document. In this
assessment of vulnerability of the economy of Sierra Leone
to climate change it is necessary first to characterize the
current climate of Sierra Leone (based on current and last
data of the previous communication) and develop future
climate change scenarios from it. Hence, the main purpose of
this study and the report is to develop current climate and
future climate change scenarios to be made available to the
sectoral teams for their use in their inter-disciplinary
vulnerability assessments.
Needs of inter-disciplinary Assessment
expert Teams (Agriculture, Water
Resources, Coastal Resources, etc.)
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Agricultural Sector:
A minimum of 50 years daily weather data for each site
for minimum temperature, Maximum temperature, rain fall, solar radiation and shine
hours.
Grassland/Livestock:
50 years continuous measure of maximum and minimum
temperature, rainfall, wind and solar radiation.
Forestry Sector: A 50 years annual temperature and precipitation.
Water Resources Sector: Mean monthly temperatures and precipitation.
Health Sector: Current climate data including maximum and minimum sectional
temperatures, precipitation levels and average monthly temperatures by succulent
geographical and political areas possible.
Fisheries and Coastal Zone:
Air and water temperatures and pollution levels.
The characterized fifty years climate is used here to construct future climate change
scenarios.
Present Country Climate Situation
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As a typical tropical country within latitudes 7º and 10º N and being on the
Atlantic on the West at Longitude 13º W extending eastward to longitude
10º W, the country has two main seasons of wet and dry. The wet season is
associated with the southwesterly tropical maritime monsoon with pressure
and drift originating from the St. Helene High Pressure belt gradually
encompassing northwest. The cumulative effect is a highly developed
convective activity with its accompanying thunderstorm especially during the
start and withdrawal of the rain season. Despite these two main seasons,
the seasonal pattern variation can further be classified based on the
predominant wind direction (since it is the weather controlling factor here)
into the following: Dry and Wet seasons also sub divided into :
Dry {Hamattern or Northern Monsoon(December-February), Pre-monsoon
(April-May)}
Wet {Southern Monsoon (June-September), Post Monsoon (OctoberNovember)}
The Average Monthly Rainfall (mm) of Sierra Leone at selected Stations for the Period
1961-2010
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Temperatures:
Seasonal temperature variations in Sierra Leone are not large, where the
amplitude of the average annual mean temperature (middle curve below)
of Sierra Leone is about 3OC. Maximum temperature shows larger
amplitude (about 5OC) while minimum temperature has an amplitude of
about 2OC; (see figures below) Highest temperatures are recorded in March
and resonate between February and April while lowest temperatures are
recorded in July and August. The low temperatures in July and August are
mainly due to almost continuous cloudiness and rain during these months of
the south western Monsoon Season described in preceding sections of this
report
Figure 3: Mean Monthly Temperature (0C) of Sierra Leone for the period 1961-2010
40
35
TEMPERATURE 0C
30
25
Maximum
Minimum
Mean
20
15
10
5
0
Jan
Feb
Mar
Apr
May
Jun
MONTHS
Jul
Aug
Sep
Oct
Nov
Figure 3b: Average Monthly Temperatures of Sierra Leone for 1961-2010
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4
3
2
TMAX
TMIN
TMEAN
3
0
O
C
2
8
2
6
2
4
2
2
2
0
Jan.
Feb.
Mar.
Apr.
May
June
July
Aug.
Sept.
Oct.
Nov.
Dec.
Solar Radiation and Evaporation
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The solar radiation received at the top of the earth's atmosphere on a
horizontal surface is called the extraterrestrial (solar) radiation, Ra. The
radiation striking a surface perpendicular to the sun's rays at the top of the
earth's atmosphere, called the solar constant, is about 0.082 MJ m-2 min-1.
If the sun is directly overhead, the angle of incidence is zero and the
extraterrestrial radiation Ra is equal to the solar constant (0.0820 MJ m-2
min-1). As seasons change, the position of the sun, the length of the day and,
hence, Ra change as well. Extraterrestrial radiation is thus a function of
latitude, date and time of day. The amount of radiation reaching a
horizontal plane is known as the solar radiation, Rs. For a cloudless day, Rs is
roughly 75% of extraterrestrial radiation.
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RFigure 4: Relationship between Extraterrestrail Radiation (Ra) and Actual Solar Radiation
(Rs) received over Sierra Leone (1961-2010)
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MJ/M2/day
30
25
Ra
Rs
20
15
10
5
0
Jan
Feb
Mar
Apr
May
Jun
Jul
MONTHS
Aug
Sep
Oct
Nov
Dec
Figure 5: Relationship between Maximum Sunshine (N) and Actual Sunshine in Sierra Leone
(1961-2010)
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12
10
8
Hrs
n
N
6
4
2
0
Jan
Feb
Mar
Apr
May
Jun
Jul
MONTHS
Aug
Sep
Oct
Nov
Dec
Figure 6: Average Monthly Evaporation in Sierra Leone for the period 1961 to 2010
250.
0
200.
0
150.
0
mm
100.
0
50.
0
0.
0
Jan
Feb Mar April May June July
Aug Sept Oct
Nov
Dec
Rainfall and Evapotranspiration in Sierra Leone for 1960-1961
CLIMATE CHANGE SCENARIOS
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In this report the current climate change scenarios for Sierra Leone was
accomplished through the use of MAGICC version 5.3 (Model for the
Assessment of Greenhouse-gas Induced Climate Change). The models used
by MAGICC have been developed in the Climatic Research Unit and the
climate model is a standard upwelling-diffusion, energy- balance model of
the form originally developed by Hoffert et al. (1980) and described by
Wigley and Raper (1987, 1992, 1993) and by Raper et al. (1996). The
GCM output from the HADCM2, UKTR, CSIRO-TR and ECHAM4 models
were used to construct the climate change scenarios.
Temperature Scenarios
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The average annual temperature of Sierra Leone for the period 1961 to
2010 and based on observed data from the meteorological stations
discussed in preceding sections is about 26.9OC. Combining this average
annual temperature with the 2*CO2 output from the GCMs, the average
annual temperature for Sierra Leone for the period 1961-2010 is projected
to increase by about 7 to 9.5 per cent above this average temperature at
2125. Figures 8a, Figure 8b and Table 2 below show the variation of this
projected increase in the annual average temperatures at 2125.
The current Climate Scenarios projected for 2025 are given in the Chart
below for HADCM, UKTR and ECHAM4 model runs.
Similar work with the CCSIRO-TR model only gave the projection for 2120
using the same country data of 1961-2010 as tabulated below.
Current Climate (1961-2010) and three projected Climate
Scenarios at 2125
Figure 8b: Projected Temperatures by the GCMs considered up t0 2125
relative to Current Climate (1961-2010) of Sierra Leone
31.
0
30.
0
O
C
29.
0
28.
0
27.
0
1961-2010
26.
0
HADCM2
UKTR
25.
0
CSIRO-TR
ECHAM4
JA
N
FE
B
MAR
AP
R
MAY
JU
N
JUL
AUG
SE
P
OCT
NOV
DEC
Precipitation Scenarios
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The following two Figures show current (1961 -2010) and projected rainfall
to 2125. Both figures show that monthly (Figure 9) and annual (Figure 10)
rainfall values at 2125 under the ECHAM4 and HADCM2 models are
similar to current climate rainfall values
. However, the CSIRO-TR and UKTR models show a decrease in rainfall by
about 3.5% and 9% respectively below current monthly and annual rainfall
values.
Figure 9: Projected Mean Monthly Rainfall of Sierra Leone at
2125
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0
19612010
CSIRO-TR
HADCM2
UKTR
ECHAM4
UKMOEQ
60
0
milli
metr
es
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0
40
0
30
0
20
0
10
0
0
JA
N
FE
B
MAR
AP
R
MAY
JU
N
JUL
AU
G
SE
P
OCT
NOV
DEC
Figure 10: Current and Projected Mean Annual Rainfall of Sierra Leone to 2125
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0
m
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l
l
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m
e
t
r
e
s
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270
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260
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250
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230
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220
0
1961-2010
HADCM2
UKTR
CSIRO-TR
ECHAM4
UKMOEQ
Evaporation
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Mean monthly evaporation for current climate (1961-2010)
and projected values at 2125 by GCMs are illustrated in
Figure 11. During the period from January to May monthly
evaporation values under current climate are higher than all
projects to 2125 by the GCMs except for the ECHAM4 model
whose projection is higher than current climate values and
projects by all other GCMs used in this study.
The monthly variations in evaporation shown in Figure 11 above
are markedly reflected in the mean annual evaporation values
illustrated in Figure 12 below. Variations about the mean
annual evaporation of 1690 mm under current climate (19612010) show an increase of about 6.5% under the ECHAM4
model but a decrease of about 20% under the HADCM2,
8.5% under the UKTR and 5% under the CSIRO-TR models
Figure 11: Projected Mean Monthly Evaporation of Sierra Leone at 2125
30
0
19612010
UKTR
ECHAM4
25
0
HADCM2
CSIRO-TR
m
m
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0
15
0
10
0
5
0
JAN
FEB
MAR
APR
MAY
JUN
JUL
AUG
SE
P
OCT
NOV
DEC
Figure 12: Current and Projected Mean Annual Evaporation of Sierra Leone to 2125
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169
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1600
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129
m 1400
i
l 1200
l
i 1000
m
e
800
t
r
600
e
s
400
200
0
1961-2010
HADCM2
UKTR
CSIRO-TR
ECHAM4
Solar Radiation
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From Table 3 (from the main body of the report)
the estimated average annual solar radiation
received at the surface is about 6021 MJ/m2/year
for the period 1961 to 2010. Based on projects
using GCM outputs this is expected to decrease by
12% under the HADCM2, 9% under the UKTR, and
3% under the CSIRO-TR models but increase by 5%
under the ECHAM4 model.
CO2 levels and Sea Level Rise
Scenarios:
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Based on the best reference MAGICC/SCENGEN
projects CO2 concentration of about 350 parts per
million (ppm) for the 1990s. Double CO2
concentration levels of about 580 ppm are likely to
be achieved by 2075 and about 700 ppm by 2100
and to about 950 ppm by 2025. Sea level rise (SLR)
scenarios adopted in this study are 0.2 m as baseline,
and 0.5 m, 1.0 m, and 2.0 m by 2100 and by 3.5 m
(IPCC, 1990) and 5.0 by 2125.
Sea Level Rise Affecting the Lungi-Kintoki area
Sea Level rise is having marked effects on our coast line and coastal infrastructures. In the
above picture, the sea has eaten more that 10m length of land in just 15 years. A visit to
Konakry Dee will show that the beautiful presidential resort of President Stevens’ days is no
more as the sea has taken over the whole area
Sea Level Rise does not spare buildings
Sea Level Rise is seen here affecting the little stream which in turn is destroying
the wall fence of this Hotel that was under construction. It has been abandoned
since.
In Sierra Leone the danger posed by global warming and indeed sea level rise
is seen here eating well into the land and destroying the trees and other things
in its way
One of the areas where the sea level rise is destroying both the environment
and property. See at way the people have resulted to constructing structures at
the far side.
Here notice the former position of land some five years
ago.
Conclusions and Recommendations
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Stabilization of the concentrations of greenhouse gases in the atmosphere at all levels will
eventually entail substantial reductions in CO2 emissions. Long term stabilization of
atmospheric CO2 concentrations requires that net anthropogenic CO2 emissions ultimately (over
centuries) decline to the level of persistent natural sinks, which are expected to be less than
0.2 PgC/yr (IPCC WG I TAR, 2001). IPCC (2001) concludes that temperatures will continue to
warm decades after the CO2 concentrations have stabilized due largely to thermal inertia. As
temperatures are projected to increase decades after stabilization of concentrations of CO 2,
climate change will not be obviated and, therefore, mitigation of emissions of greenhouse
gases and their concentration into the atmosphere and adaptation to the impacts of climate
change will be necessary to minimize damages and to maximize opportunities. More research
into the climate system is necessary.
For Sierra Leone to effectively join the international family in these efforts some important
priority activities need to be undertaken at the national and regional levels. These will enable
the effective recording and monitoring of climate data and phenomena leading to
improvement of studies and climate information. The following activities are the priority
activities to be considered.
Recommendations Continued
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Strengthening the climate data base of the Meteorological
Department
Rehabilitation and reopening of more climate data collection and
monitoring stations
Training of Personnel
Speeding up the department’s semi-autonomous process of the
Agency creation
Provision of necessary logistics and incentives for this highly
scientific discipline for expected service delivery
Education and sensitization of the public on climate change issue
Create a National Climate Change Committee and Secretariat
Undertake Climate Research with interested parties
Thank you for your attention
BY
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DENIS LANSANA
and
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ALPHA BOCKARIE