Global Warming and Sea Level Rising: Impact on Bangladesh Agriculture and Food Security

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Welcome to the Presentation on
Global Warming and Sea Level Rising Impact on
Bangladesh Agriculture and Food Security
by Prof. Dr. M.A. Halim Khan, Principal
Investigator Dr. M.A. Awal, Co-Investigator Depa
rtment of Crop Botany Bangladesh Agricultural
University Mymensingh-2202, Bangladesh
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Why global warming?
Fig. 1 Green house gasses and their contribution
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The emissions of CO2 have been dramatically
increased since 1958 and are still increasing by
about 1.5 ppmv/annum
Fig. 2 Time series of CO2 concentration
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During 1880-1935, the temperature anomaly was
consistently negative.  In contrast, from 1980 it
is constantly positive having highest anomalies
of 0.4 to 0.6oC.
Fig. 3 Time series of global temperature anomaly
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The IPCC predicted global temperature increase in
the 21st century as     Low 1oC     Medium
2oC     High 3.5oC.
Fig. 4 Global temperature projections to the
year 2100
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Fig. 5 Annual glacier thickness change
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Fig. 6 Sea-level rise since 1880
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Fig. 7 Modeled sea level rise from 1765 to 2100.
The uncertainty range is for uncertainty in the
climate sensitivity only.
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Consequences of global warming
Broader perspective
Regional perspective
? Shifting in climatic patterns, arid
semi-arid regions, vegetation forests
? Erratic rainfall, drought floods
? Cold hot spells
? Drought desertification
? Tidal surges
? Inundation of low-lying areas
? Melting of glaciers ices
? Thermal expansion of sea water sea-level
rising
? Increasing coastal salinity
? Cyclones tornadoes
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Consequences of global warming sea level rising
on Bangladesh agriculture and food security
Long term effects
Disastrous effects
? Occurrence of frequent cyclones, tornadoes,
floods droughts
? Inundation of low-lying coastal areas
? Incursion by salinity in coastal cultivable
lands loss of soil fertility ecosystem
productivity
? Infrastructural damage including roads
highways, dwelling houses embankments
? Changes in the land-use pattern that
includes coastal agriculture, fisheries, live
stocks mangroves
? Erosion of river banks, estuaries, channels
canals
? Destruction of standing crops, shrimp
hatcheries fresh water aquifers in the
coastal areas
All these should have cumulative effects on
Food security creation of climatic refugees
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Why the global warming/sea-level rising is
important to Bangladesh?
Presence of a specialized cone/funnel shaped Bay
guides most of the cyclones to strike Bangladesh
coast
Fig. 8 Map of the Indian sub-continent and Bay
of Bengal
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Objectives ? To evaluate the status of low-lying
coastal areas and off-shore islands, ? To
asses the vulnerability of coastal population
due to predicted sea level rising, ? To find
out the agricultural enterprises which under
the immediate threat of up-coming sea level
rising, ? To explore the tactic regarding food
security against predicted sea level rising.

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Major activities ? Data collection -
secondary primary ? Case studies ? Field
study ? Chemical analysis ? Data analysis
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Collection of secondary data ? Relevant
information on global warming and sea-level
rising have been accumulated by consulting
books, journals, periodicals, browsing
internets, personal communications, attending
seminars and symposia and visiting various
institutes/organizations. ? Climatic parameters
like temperature, humidity, rainfall, cyclones,
tidal surges etc. and geo-morphological
information covering elevation, estuaries,
embankments, floods, tides and projected areas
of inundation etc. of the coastal regions of
Bangladesh have been collected by visiting
pertinent organizations and websites.
Collection of primary data ? The land-use
patterns, managements and socio-economic aspects
of the coastal people of Barisal, Khulna
and Chittagong Divisions have been
collected by case studies together with the
collection of water and soil samples for
salinity studies.
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Study sites
Fig. 9. Locations of sites visited for studies
are shown in the boxes
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Trends of variation of seasonal mean maximum
temperature
Despite great fluctuations the mean temperature
in pre-monsoon appeared to be static while
south-west monsoon and post-monsoon temperatures
are continually increasing since 1961
Fig. 10 Country average (mean from 24-34
stations throughout the country) temperature in
Bangladesh from 1961 to 2007.
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Trends of maximum/minimum temperatures in
Bangladesh
Fig. 11 Country average (mean from 24-34
stations throughout the country) temperature of
Bangladesh from 1961 to 2007.
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Trends of seasonal and annual total rainfall in
Bangladesh
Extreme yearly fluctuations are noticeable since
1961. However, the regression lines computed from
5-year moving average indicate increasing trend
in the amount of total rainfall
Fig. 12 Country average (mean from 24-34
stations throughout the country) rainfall in
Bangladesh from 1961 to 2007.
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Table 1 Projected global warming and rainfall
scenarios in Bangladesh
Year Sea level rise (cm) Temperature increase (oC) Temperature increase (oC) Temperature increase (oC) Rainfall fluctuation compared to 1990 () Rainfall fluctuation compared to 1990 ()
Year Sea level rise (cm) Monsoon Winter Annual Monsoon Winter
2030 14 0.8 1.1 1.0 6 - 2
2050 32 1.1 1.6 1.4 8 - 5
2100 88 1.9 2.7 2.4 12 - 10
Source Coastal Developmental Strategy, 2006.
Water Resources Planning Organization, Ministry
of Water Resources, GOB
Table 2 Land area inundation due to projected
sea-level rise in Bangladesh
Year Sea level rise (cm) of total land area inundation in Bangladesh
2030 14 8
2050 32 10
2100 88 16
Barisal, Patuakhali and Khulna regions are most
at risk from sea level rise.
Source Coastal Developmental Strategy, 2006.
Water Resources Planning Organization, Ministry
of Water Resources, GOB
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Table 3 Features of vulnerable districts in the
coastal zones of Bangladesh
SL. No. Name of district Area (km2) Total population of total country population Nature of vulnerability Nature of vulnerability Nature of vulnerability
SL. No. Name of district Area (km2) Total population of total country population Salinity Tidal surge Cyclones
1 Borguna 1,832 845,060 0.682 v v v
2 Barisal 2,791 2,348,440 1.896 v v v
3 Bhola 3,403 1,703,200 1.375 v v v
4 Jhalokati 758 692,680 0.559 v v v
5 Patuakhlai 3,205 1,464,800 1.183 v v v
6 Pirojpur 1,308 1,099,780 0.888 v v v
7 Bagerhat 3,959 1,516,820 1.225 v v v
8 Jessore 2,567 2,469,680 1.994 v
9 Khulna 4,395 2,357,940 1.904 v v v
10 Narail 990 694,900 0.561 v v
11 Satkhira 3,858 1,845,120 1.490 v v v
12 Chandpur 1,704 2,241,020 1.810 v v v
13 Chittagong 5,283 6,543,860 5.284 v v v
14 Coxs Bazar 2,492 1,759,560 1.421 v v v
15 Feni 928 1,205,980 0.974 v v v
16 Laksmipur 1,458 1,486,540 1.200 v v v
17 Noakhali 3,601 2,570,640 2.076 v v v
18 Gopalganj 1,490 1,151,800 0.930 v
19 Shariatpur 1,181 1,080,680 0.873 v v
Total 47,203 35,078,500 28.323
Source BBS, 2004
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Topography of Bangladesh
Most of the coastal parts and associated islands
of Khulna, Barisal and Chittagong Divisions lie
within 1m from sea level where incursion of
saline water is common. And these areas will be
inundated and unsuitable for crop production due
to sea-level rise in next 50 years
Fig. 13 Topographic map of Bangladesh
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Fig. 14 Inundation pruned area of Bangladesh due
to up coming sea-level rise
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Table 4 Present land-use patterns in the coastal
zones of Bangladesh
Division Major cropping patterns Major cropping patterns Major cropping patterns
Division Aman (Jul-Nov) Boro/Rabi (Dec-May) Aus/Kharif (May-Aug)
Barisal T Aman, broadcast Aman Mostly fallow, scattered winter vegetables pulses Mostly fallow, scattered Aus
Khulna Shrimp, scattered T Aman, mixed shrimp T Aman Shrimp/fallow/ mixed Shrimp Boro Shrimp/Aus
Chittagong T Aman, broadcast Aman Pulses, groundnut, soybean, watermelon, vegetables, chilli, scattered Boro Aus, fallow
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Table 5 Level of salinity of soil and water as
observed in some selected coastal areas
SL. No. Locations and descriptions of collected samples Electric conductivity (ds M-1) Electric conductivity (ds M-1) Remarks
SL. No. Locations and descriptions of collected samples Soil sample Water sample Remarks
1. Patharghata, Barguna 4.21 - Moderately saline
2. Rayenda Khal, Sarankhola, Bagerhat (21 May 2008) - 2.66 Slightly saline
3. Pankuchi river (1130 AM, 21 May 2008) - 4.17 Moderately saline
4. Pashur river, Mongla, Bagerhat (1230 PM, tide time, 22 May 2008) - 28.70 Strongly saline
5. Janer Par, Sarankhola, Bagerhat (sample collected on 20 April 2008) 1.52 - Non-saline
6. East Bridge, 2 Khonta Kata, Sarankhola, Bagerhat (sample collected from bil at 14 cm depth on 22 April 2008) 0.77 - Non-saline
7. Bhashanzal, Morolganj, Bagherhat, samples collected on 21 May 2008. 0.75 8.54 Non-saline/saline
8. Totar Bazar, Subarnachar, Noakhali (samples collected from on growing T Aman field on 24 September 2008) 2.35 0.30 Slightly saline/non-saline
9. Char Jabbar, Subarnachar, Noakhali 6.66 - Moderately saline
10. Jubili Char, Noakhali (sample collected on 24 September 2008) - 0.36 Non-saline
11. Chairmangat, Boyarchar, Hatiya channel (sample collected at 1200 PM on 24 September 2008) - 0.18 Non-saline
Note Electrical conductivity (Ec) 0-2, 2.1-4,
4.1-8, 8.1-15 and gt15 ds M-1 respectively
indicate non-saline, slightly saline, moderately
saline, saline and strongly saline
conditions for crop production (source USDA,
Agriculture Hand Book 60, cited from Khan et
al., 2008).
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Fig. 15 In spite of nearness to water sources
vast cultivable land remain fallow during the
Boro season in places of Barisal Division
(photographs taken on 16 April 2008).
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Fig. Vast lands are remained fallow in spite of
water in Bagherhat (photographs taken on 21 May
2008).
Fig. 16 In spite of nearness to water sources
vast cultivable land remain fallow during the
Boro season in places of Bagerhat
of Khulna Division (photographs taken on 21 May
2008).
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Fig. 17 Boro rice (hybrid var. Alo) has been
successfully cultivated in Bhashanzal, Morolganj
of Bagherhat by using the locally available
surface water (photographs taken on 21 May 2008).
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Fig. 18 Shrimp cultivation is more popular than
paddy in Mongla, Khulna region (pictures taken on
22 May 2008).
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Fig. 19 Coastal zone climate and land-use
patterns scenarios and model for food security
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Suggestions Conclusion ? Advancing the present
cropping patterns in both Boro and Aman
seasons by a fortnight should go a long way
in avoiding the coastal cyclones and will mean a
good harvest of rice, the main cereal of the
country. ? Introduction of salt-tolerant Boro
rice (also maize) will further contribute to
additional production of food grains and
boost food security. ? Development of submerged
tolerant rice varieties capable of thriving
tidal surges/floods should be the alternative
option for food security.
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Thanks