(13 in South 24 Parganas and 6 in North 24 Parganas). This reduction of forest
cover has been caused by both natural factors and human intervention (Hazra et al.
2003). In recent years, certain changes have been noticed in the climate of this
region. Scholars are of the opinion that the span of the summer season has increased
while the span of winter has decreased. Rainfall has increased by one and half times
from what it was 15 years ago. The monsoon season are now getting delayed by
approximately 15–20 days (Das 2006). Surface air temperature databases of the
Sunderbans and adjacent parts of the Bay of Bengal have been analyzed by the
School of Oceanography, Jadavpur University. They have noticed an increasing
trend in the yearly rise in temperature. Their finding corroborates with the existing
global warming phenomena. Temperature increase is found to be at the rate
0.019 % per year (Hazra et al. 2002).
The Sunderbans is presently under the threat of severe coastal erosion due to
relative sea level rise (Hazra 2002). The analysis of 50 years of data for Mean Sea
Level (PSMSL) from three of the four data stations in the Hugli estuary shows sea
level increase between +0.76 and +5.22 mm/year at different locations in the
Sunderbans (Nandy and Bandypadhyay 2011). The tide gauge data of Sagar Island
observatory for the period 2002–2009 indicated a rise in the Relative Mean Sea
Level (RMSL) at the rate of 12 mm/year during the decade (Hazra 2010).
Considering the record of past 25 years, the rate of relative sea level rise comes close
to 8 mm/year, which of course is significantly higher than the rate of 3.14 mm/year
observed during the previous decade (Hazra 2002). Besides global warming and
subsequent thermal expansion of water, subsidence of the Bengal Delta at 2–
4 mm/year due to compaction of silt and other local causes may be responsible for
the exceptionally high rate of relative sea level rise in the Indian Sundarbans. The
mean tide level in the Sunderbans seems to vary in close correlation with sea surface
temperature (SST) in the Bay of Bengal (Delta Vision 2011, p. 27). Current projections estimate that the temperature in the Sunderbans will rise by 1 °C by 2050
(Hazra et al. 2002). Between 2002 and 2009, the SST showed a rising trend at the
rate of 0.0453 °C/year and reached the highest level in 2009 which confirms with a
earlier study done by Singh (Singh 2002, cited in Delta Vision 2011, p. 29), that had
predicted a decadal increase of about 0.4–0.5 °C. Increase in SST has a bearing on
chemical composition of sea water in terms of increased acidification and decreased
dissolved oxygen levels (Hazra 2010, cited in Delta Vision 2011). Considering the
present relative sea level rise at 3.14 mm per year, it is estimated that by the year
2050, the compound sea level elevation will become close to 1 m and this estimated
rise of sea level will pose serious problems during the pre- and post-monsoon phase
when most of the cyclonic storms occur (Hazra et al. 2002, p. 10). The threat to
Sunderbans in a 2 degree rise in temperature was very big, now with the 4° rise, it
going to be a Herculean task to save these islands.
There seems to be a direct correlation between the amount of erosion and
submergence with the rate of relative rise and fall of sea level in different island
segments as found by the School of Oceanography. The impact of such erosion–
accretion processes and sea level rise induced changes is predicted to be visible
along the coastal zones of the island system along the tidal creeks and mangrove
Is There a Tomorrow?: The Story of Survival …
365
cover has been caused by both natural factors and human intervention (Hazra et al.
2003). In recent years, certain changes have been noticed in the climate of this
region. Scholars are of the opinion that the span of the summer season has increased
while the span of winter has decreased. Rainfall has increased by one and half times
from what it was 15 years ago. The monsoon season are now getting delayed by
approximately 15–20 days (Das 2006). Surface air temperature databases of the
Sunderbans and adjacent parts of the Bay of Bengal have been analyzed by the
School of Oceanography, Jadavpur University. They have noticed an increasing
trend in the yearly rise in temperature. Their finding corroborates with the existing
global warming phenomena. Temperature increase is found to be at the rate
0.019 % per year (Hazra et al. 2002).
The Sunderbans is presently under the threat of severe coastal erosion due to
relative sea level rise (Hazra 2002). The analysis of 50 years of data for Mean Sea
Level (PSMSL) from three of the four data stations in the Hugli estuary shows sea
level increase between +0.76 and +5.22 mm/year at different locations in the
Sunderbans (Nandy and Bandypadhyay 2011). The tide gauge data of Sagar Island
observatory for the period 2002–2009 indicated a rise in the Relative Mean Sea
Level (RMSL) at the rate of 12 mm/year during the decade (Hazra 2010).
Considering the record of past 25 years, the rate of relative sea level rise comes close
to 8 mm/year, which of course is significantly higher than the rate of 3.14 mm/year
observed during the previous decade (Hazra 2002). Besides global warming and
subsequent thermal expansion of water, subsidence of the Bengal Delta at 2–
4 mm/year due to compaction of silt and other local causes may be responsible for
the exceptionally high rate of relative sea level rise in the Indian Sundarbans. The
mean tide level in the Sunderbans seems to vary in close correlation with sea surface
temperature (SST) in the Bay of Bengal (Delta Vision 2011, p. 27). Current projections estimate that the temperature in the Sunderbans will rise by 1 °C by 2050
(Hazra et al. 2002). Between 2002 and 2009, the SST showed a rising trend at the
rate of 0.0453 °C/year and reached the highest level in 2009 which confirms with a
earlier study done by Singh (Singh 2002, cited in Delta Vision 2011, p. 29), that had
predicted a decadal increase of about 0.4–0.5 °C. Increase in SST has a bearing on
chemical composition of sea water in terms of increased acidification and decreased
dissolved oxygen levels (Hazra 2010, cited in Delta Vision 2011). Considering the
present relative sea level rise at 3.14 mm per year, it is estimated that by the year
2050, the compound sea level elevation will become close to 1 m and this estimated
rise of sea level will pose serious problems during the pre- and post-monsoon phase
when most of the cyclonic storms occur (Hazra et al. 2002, p. 10). The threat to
Sunderbans in a 2 degree rise in temperature was very big, now with the 4° rise, it
going to be a Herculean task to save these islands.
There seems to be a direct correlation between the amount of erosion and
submergence with the rate of relative rise and fall of sea level in different island
segments as found by the School of Oceanography. The impact of such erosion–
accretion processes and sea level rise induced changes is predicted to be visible
along the coastal zones of the island system along the tidal creeks and mangrove
Is There a Tomorrow?: The Story of Survival …
365