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
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 CO 2 levels and Sea Level Rise Scenarios Conclusions and Recommendations
PURPOSE AND SCOPE OF THE STUDY
• • 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.)
• • • • • • Agricultural Sector: for minimum temperature, Maximum temperature, rain fall, solar radiation and shine hours.
A minimum of 50 years daily weather data for each site
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: The characterized fifty years climate is used here to construct future climate change scenarios.
Air and water temperatures and pollution levels.
Present Country Climate Situation
• • • 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 (October November)}
The Average Monthly Rainfall (mm) of Sierra Leone at selected Stations for the Period 1961-2010
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 3 O C. Maximum temperature shows larger amplitude (about 5 O C) while minimum temperature has an amplitude of about 2 report O C; (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
Figure 3: Mean Monthly Temperature (0C) of Sierra Leone for the period 1961-2010
40 35 30 25 20 15 10 5 0 Jan Feb Mar Apr May Jun
MONTHS
Jul Aug Sep Oct Nov Maximum Minimum Mean
2 2 2 0 2 6 2 4 3 0 2 8 3 4 3 2 Figure 3b: Average Monthly Temperatures of Sierra Leone for 1961-2010 Jan.
Feb.
Mar.
Apr.
May June TMAX July Aug.
TMIN Sept.
Oct.
TMEAN Nov.
Dec.
Solar Radiation and Evaporation
The solar radiation received at the top of the earth's atmosphere on a horizontal surface is called the extraterrestrial (solar) radiation, R a earth's atmosphere, called the solar constant, is about 0.082 MJ m . The radiation striking a surface perpendicular to the sun's rays at the top of the -2 min -1 . If the sun is directly overhead, the angle of incidence is zero and the extraterrestrial radiation R a 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, R a 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, R s . For a cloudless day, R s is roughly 75% of extraterrestrial radiation .
30 25 20 45 40 35 15 10 5 0 Jan
RFigure 4: Relationship between Extraterrestrail Radiation (Ra) and Actual Solar Radiation (Rs) received over Sierra Leone (1961-2010)
Feb Mar Apr May Jun Jul
MONTHS
Aug Sep Oct Nov Dec Ra Rs
Figure 5: Relationship between Maximum Sunshine (N) and Actual Sunshine in Sierra Leone (1961-2010)
14 12 10 8 6 4 2 0 Jan Feb Mar Apr May Jun Jul
MONTHS
Aug Sep Oct Nov Dec n N
Figure 6: Average Monthly Evaporation in Sierra Leone for the period 1961 to 2010 250.
0 200.
0 mm 150.
0 100.
0 50.
0 0.
0 Jan Feb Mar April May June July Aug Sept Oct Nov Dec
Rai nfall and Evapotranspiration in Sierra Leone for 1960-1961
CLIMATE CHANGE SCENARIOS
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
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 26.9
O C. 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 29.
0 28.
0 27.
0 26.
0 25.
0 JA N 1961-2010 UKTR ECHAM4 FE B MAR AP R HADCM2 CSIRO-TR MAY JU N JUL AUG SE P OCT NOV DEC
Precipitation Scenarios
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.
40 0 30 0 20 0 10 0 70 0 60 0 50 0 0 JA N Figure 9: Projected Mean Monthly Rainfall of Sierra Leone at 2125 1961 2010 CSIRO-TR HADCM2 ECHAM4 UKTR UKMOEQ 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 290 0 m i l l i m e t r e s 280 0 270 0 260 0 250 0 240 0 230 0 220 0 1961-2010 HADCM2 UKTR CSIRO-TR ECHAM4 UKMOEQ
Evaporation
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 (1961 2010) 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
30 0 25 0 Figure 11: Projected Mean Monthly Evaporation of Sierra Leone at 2125 1961 ECHAM4 HADCM2 CSIRO-TR 20 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 1800 1600 e t r e s m i l l i m 1400 1200 1000 800 600 400 200 0
156
1961-2010
129
HADCM2
169
UKTR
148
CSIRO-TR
178
ECHAM4
Solar Radiation
From Table 3 (from the main body of the report) the estimated average annual solar radiation received at the surface is about 6021 MJ/m 2 /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.
CO
2
levels and Sea Level Rise Scenarios:
Based on the best reference MAGICC/SCENGEN projects CO 2 concentration of about 350 parts per million (ppm) for the 1990s. Double CO 2 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
Stabilization of the concentrations of greenhouse gases in the atmosphere at all levels will eventually entail substantial reductions in CO 2 emissions. Long term stabilization of atmospheric CO 2 concentrations requires that net anthropogenic CO 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 CO 2 2 emissions ultimately (over 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
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
DENIS LANSANA
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