The probable impacts of climate change on poverty - UNDP

5.3 Changes in Sea Level and Salinity Intrusion
Change in the sea level at local level depends on several factors and therefore future sea level rise projected in
the assessment report <strong>of</strong> the Intergovernmental Panel on Climate Change (IPCC) will not be uniform all over
world. One <strong>of</strong> the critical factors related to Bangladesh coast is vertical land movement (subsidence/uplift).
Seasonal variation <strong>of</strong> salinity intrusion also depends on freshwater flow in the river system and cyclonic storm
surges.
<strong>The</strong> SAARC Meteorological Research Council (SMRC) carried out a study on recent relative sea level rise in the
Bangladesh coast. <strong>The</strong> study has used 22 years historical tidal data <strong>of</strong> the three coastal stations. <strong>The</strong> study
revealed that the rate <strong>of</strong> sea level rise during the last 22 years is many fold higher than the mean rate <strong>of</strong> global
sea level rise over 100 years, which showed the important effect <strong>of</strong> the regional tectonic subsidence. Variation
among the stations was also found. Table 5.3 represents the trend <strong>of</strong> tidal level in three costal stations.
Table 5.3 Trend <strong>of</strong> tidal surge in three coastal stations
Tidal Station Region Latitude (N) Longitude (E) Datum (m) Trend (mm/year)
Hiron Point Western 21 3.784
˚48’ 89˚28’ Char Changa Central 22 ˚ 08’
Cox’s Bazar Eastern
Source: SMRC, No. 3
A2
(High Emission Scenario)
High
Low
B1
(High Emission Scenario)
High
Low
21 ˚ 26’ 91 ˚ 59’
<strong>The</strong> Probable Impacts <strong>of</strong> Climate Change on Poverty and Economic Growth and
the Options <strong>of</strong> Coping with adverse Effect <strong>of</strong> Climate Change in Bangladesh
4.0
91 4.996
˚06’ 6.0
Sea Level Rise (cm)
2020 2050 2080
6 27 62
- 5 9
5 23 48
- 8 15
4.836 7.8
<strong>The</strong> IPCC 3rd Assessment report estimated that the global rise in sea level from 1990 to 2100 would be between 9
and 88 cm. <strong>The</strong> Third Assessment Report has also projected global sea level rise for the year 2020, 2050 and 2080
using different emission scenarios. Future projection <strong>of</strong> Global Sea Level Rise is given below.
Table 5.4 Sea Level Change under different Emission Scenarios
Recent study result revealed that about 13% more area (469,000 ha) will be inundated in monsoon due to 62 cm
sea level rise for high emission scenario A2 in addition to the inundated area in base condition. <strong>The</strong> most
vulnerable areas are the areas without polders like Patuakhali, Pirojpur, Barisal, Jhalakati, Bagerhat, Narail. Due to
increased rainfall in addition to 62cm sea level rise, the inundated area will be increased and about 16% (551,500
ha) more area will be inundated in the year 2080. On the contrary, in the dry season due to 62cm sea level rise
about 364,200 ha (10%) more area will be inundated (inundation more than 30cm) for A2 scenario in the year
2080. However, 15cm sea level rise has insignificant impact on inundation in dry season.
It is important to note that analyzing the <strong>impacts</strong> <strong>of</strong> sea level rise in the coastal areas need to incorporate
dynamic nature <strong>of</strong> its morphology and formation process. Bangladesh is a dynamic delta and its landmass is still
growing by gradual deposition <strong>of</strong> sediment. <strong>The</strong> average sediment accumulation rate for the last few hundred
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