Understanding climate risks and exploring adaptation strategy -
agriculture and water sector
MD. MAFIZUR RAHMAN
Professor
Department of Civil Engineering
Bangladesh University of Engineering and Technology (BUET)
International Conference on Sustainability Science in Asia, ICSS-Asia 2011
Vietnam National University, Hanoi 2-4 March, 2011
Organized by IR3S, The University of Tokyo, Vietnam National University (VNU)
Co-Organizers: AIT Vietnam and United Nations University (UNU)
Introduction
High temperature, heavy rainfall, often-excessive humidity, and
fairly marked seasonal variations are common phenomena in
climate of Bangladesh at present. Large percentage of the
population is already vulnerable to a range of natural hazards
with increasing climate variability. Climate change is expected to
aggravate the situation further by causing more frequent and
intense droughts and increasing temperatures. Safe water crisis,
shortage of food production and distress in human life are
simultaneously deepening day by day.
This presentation will show the present scenario of climate
change impact in agriculture and water sector along with its
possible adaptation strategy in Bangladesh.
Major natural disasters• Flood
• Cyclone
• Drought
• Earthquake
• Sunstroke
• Tornado
Major man-made disasters• Setting of fires
• Epidemic
• Deforestation
• Pollution due to prawn cultivation
• Chemical pollution.
Minor natural disasters• Cold wave
• Snow fall
• Thunder storm
Minor man-made disasters:• Road and train accidents
• Accidents due to festivals
• Food poisoning (poisoned food)
• Death due to excessive drink
• Industrial disaster/ crisis
• Rehabilitation
• Acid rain
• Riots
• Environmental pollution
• War
DroughtDrought is a severe natural phenomenon which at some
intervals occurs in Bangladesh and causes disastrous crop
failures.
In 1979 the country was hit by a severe drought, which was
termed by many as the worst in the recent past.
Droughts of 1957 and 1972 were of severe nature.
Specialty of Drought in Bangladesh lies in the fact that
Bangladeshi people are not familiar with this relatively
new event of Climate change
Trend of Climatic Parameters
• Dryness and drought are the phenomena derived from the
imbalance in climatic parameters.
• In this study, the trends of seasonal as well as annual
rainfall and seasonal temperature have been analyzed to
get the patterns of seasonal dryness and drought in
Bangladesh.
Seasonal Rainfall Patterns
• North-west region of the country is generally considered asthe drier one. Observations on Rajshahi show that rainfallshave been increased over the considered period of time in allseasons except in monsoon.
• Temporal plots of the seasonal rainfall at all stations of thenorth-west region have shown increasing trends except inRajshahi during monsoon and in Chuadanga at winter.
• Pre-monsoon, monsoon and winter have become drier inComilla due to decreasing trends of rainfall in central region.
• In south-east part, pre-monsoon and monsoon rainfalls havebeen decreased during pre-monsoon and monsoonrespectively.
Seasonal Rainfall Patterns
• Madaripur has the maximum negative slope of 9.61 mm/year,which indicates the station getting the highest dryness over timeduring pre-monsoon. Again the rate of getting dryness is theminimum in Chandpur having the minimum negative slope of0.38 mm/year.
• Comilla has got the driest monsoon with the rainfall trend having
maximum negative slope of 12.41 mm/year during monsoon.
• The negative slope of temporal trend of post-monsoon rainfall is
the maximum in Comilla (-1.48 mm/year), indicating the driest
post-monsoon in Comilla.
• The rate of decrease of winter rainfall is the maximum in Tangail,
which is indicated by the maximum negative slope of 2.20
mm/year.
Seasonal Temperature Patterns
• Increase in temperature instigates increase in
evaporation as well as evapotranspiration and hence
decrease in available water.
• Therefore, increase in seasonal temperature is a
critical issue to be studied to assess seasonal drought
scenario throughout the country.
Temperature Trends
Regional Patterns
• In the north-west and north-east regions of the country, no occurrence of
increasing temperature has been found, rather temperatures have been
observed to decline over the considered period of time.
• In central region, monsoon and post-monsoon temperature have been
increased in Dhaka. Monsoon temperature has also been increased in
Tangail of this region.
• From the temperature patterns of south-west region, it is found that
monsoon temperature has been increased in Barisal and Satkhira.
• Analysis on south-east region of the country represents that post-monsoon
temperatures have shown increasing trends in Feni, Chittagong and Cox’s
Bazar. Again, monsoon temperature has been found to be increased in
Cox’s Bazar.
Temperature Trends
Seasonal Patterns
• The maximum positive slope of temperature trend has been found as0.03 °C/year in Tangail, indicating maximum dryness among other drierstations during monsoon.
• Faridpur has become the driest having the maximum positive slope ofpost-monsoon temperature of 0.03 °C/year.
• The maximum positive slope of winter temperature trend has been foundin Patuakhali as 0.13 °C/year.
• It can be noted here that monsoons in Faridpur and Cox’s Bazar havebecome drier due to decreased rainfall (-2.21 mm/year and -0.07 mm/yearrespectively) as well as increased temperature (+0.02 °C/year and+0.01 °C/year respectively).
(a) Dryness map considering rainfall in winter 1999
(b) Dryness map considering temperature in winter 1999
(c) Dryness map considering rainfall and temperature in winter 1999
(a) (b) (c)
Impacts of Climate Change on
Some Crops of Some Selected Areas
Local Transplant Aman => Comilla District
Wheat => Dinajpur District
Potato => Bogra District
Mung bean => Jessore District
Impacts of Climate Change on Rice (Local Transplant Aman)
Rice (T. Amam) y = 0.0118x - 22.05
R2 = 0.1188
1.2
1.3
1.4
1.5
1.6
1990 1995 2000 2005Year
Yie
ld (
T/H
a)
Variation of T. Aman yield during the period 1992-2004.
Impacts of Climate Change on Wheat
Wheaty = -0.0038x + 9.6398
R2 = 0.0025
1.4
1.6
1.8
2
2.2
2.4
2.6
1991 1993 1995 1997 1999 2001 2003 2005Year
Yie
ld (
T/H
a)
Variation of wheat yield during the period 1992-2005.
Impacts of Climate Change on Potato (Local)
Potato
y = 0.1088x - 210.12
R2 = 0.5047
6
7
8
9
1990 1995 2000 2005
Year
Yie
ld (
T/H
a)
Variation of potato yield during the period 1992-2004
Impacts of Climate Change on Pulse (Mungbean)
Mungbean
y = -0.0119x + 24.411
R2 = 0.5701
0.5
0.6
0.7
0.8
1990 1992 1994 1996 1998 2000 2002 2004 2006
Year
Yie
ld (
T/H
a)
Variation of mungbean yield during the period 1992-2004.
Simulated Yield for Rice y = 0.0116x + 1.4556
R2 = 0.6693
0
0.5
1
1.5
2
2.51992-9
3
1996-9
7
2000-0
1
2004-0
5
2008-0
9
2012-1
3
2016-1
7
2020-2
1
2024-2
5
2028-2
9
2032-3
3
2036-3
7
2040-4
1
2044-4
5
2048-4
9
Year
Su
mu
late
d Y
ield
(T/H
a)
Predicted rice (T. Aman) yield up to the year 2050.
Simulated Yield for Wheaty = -0.0088x + 2.0182
R2 = 0.3544
0
0.5
1
1.5
2
2.5
3
1992-9
3
1997-9
8
2002-0
3
2007-0
8
2012-1
3
2017-1
8
2022-2
3
2027-2
8
2032-3
3
2037-3
8
2042-4
3
2047-4
8
Year
Sim
ula
ted
Yie
ld(T
/Ha)
Predicted wheat yield up to the year 2050.
Simulated Yield for Potato y = 0.0339x + 7.1469
R2 = 0.4461
0
2
4
6
8
10
12
1992-9
3
1996-9
7
2000-0
1
2004-0
5
2008-0
9
2012-1
3
2016-1
7
2020-2
1
2024-2
5
2028-2
9
2032-3
3
2036-3
7
2040-4
1
2044-4
5
2048-4
9
Year
Sim
ula
ted
Yie
ld (
T/H
a)
Predicted potato yield up to the year 2050.
Simulated Yield for Mungbean
y = -0.0037x + 0.7037
R2 = 0.5446
0
0.2
0.4
0.6
0.8
1
1992-9
3
1996-9
7
2000-0
1
2004-0
5
2008-0
9
2012-1
3
2016-1
7
2020-2
1
2024-2
5
2028-2
9
2032-3
3
2036-3
7
2040-4
1
2044-4
5
2048-4
9
Year
Sim
ula
ted
Yie
ld (
T/H
a)
Predicted mungbean yield up to the year 2050.
• Agriculture is the main economic activity in Dinajpur.Because of the variety of physical conditions inDinajpur, cropping systems and crops varyconsiderably
– Kharif-I
• The Kharif-I season includes the period of early monsoon. B.Aus is themajor crop of this season
– Kharif-II
• The Kharif-II season includes the period of late monsoon. The main cropof this season, which is T. Aman depends on rainwater
– Rabi
• A number of crops are grown in the Rabi season. Boro is the primaryirrigated rice crop grown in this season, This crop has the highest recordof water demand among all crops
25
• Climate change scenarios comprise of greenhouse gas emission scenarioand regional pattern of climate change
• Emission scenario– IS92a emission scenario was selected for this study
• Climate change projection– The results of the HADCM2 and UKTR transient experiment models were used for
study area HADCM2 is regarded as one of the leading models in the world. UKTR hasbeen broadly used for impact assessment studies in different countries.
• Climate ModelHADCM2» Outputs obtained for 2050
» Outputs obtained for 2070
• Climate Model UKTR» Outputs obtained for 2050
» Outputs obtained for 2070
26
27
Assessment of the impact of climate change on Evapotranspiration…
Effects of Climate Change on Monthly evapotranspiration
28
Assessment of the impact of climate change on Crop Water Requirement…
Percentage of Change of Crop Water Requirement of B.Aus due to Climate Change
29
Assessment of the impact of climate change on Crop Water Requirement…
Percentage of Change of Crop Water Requirement ofT.Aman due to Climate Change
30
Assessment of the impact of climate change on Crop Water Requirement…
Percentage of Change of Crop Water Requirement ofBoro due to Climate Change
Solution
• Change of cropping pattern.
• Irrigation
To keep soil moisture and ground water level in acceptable limit the
following techniques can be adopted
– Infiltration ponds and basins
– Flooding
– Ditch, furrow, drains
– Deep well injection
– Recharge dam
– Channel spreading
Dhaka City
Year Population
(Million)
Growth Rate (%)
1950 0.5 -
1975 2.2 6.6
2000 10.2 7
2025 22.01 4
Average population density in Dhaka city-19286 person per sq.km. in 2005
• The total water demand for Dhaka city was increased from 150
million liter (ML) in 1963 to 2300 ML in 2010. In 1963 the total
deficit for water supply in Dhaka city was 30 ML which
substantially increased to 268 ML in 2010.
• The recharge to aquifer is very negligible because of the
geological settings and rapid urbanization.
• Consequently, groundwater table is continuously declining at an
average rate of 2m year-1, since 1986.
• This severe decline of groundwater level increasing tremendous
pressure on aquifer storage and inviting land subsidence or
other environmental hazards
Declination of Ground water
Trend of ground water depletion at different location in Dhaka city
(From 01/1992 to 01/ 2004)
DhanmondiCantonment
Sutrapur Sabujbag
Peripheral Rivers of Dhaka City
Peripheral rivers act as the
receivers of storm water,
municipal, and industrial
wastewater from Dhaka City
Over 300 outfalls of Domestic
wastewater and industrial
effluent from Dhaka city.
Effluents are discharged
indiscriminately without any
restriction.
Industrial Outlet on Lakhaya riverHazaribagh Sluice gate on Buriganga River
Dhaka Dying on Tongi cannel Chatbari Station, Mirpur on Turag RiverRiver Water Pollution
Probable Solution
• Rainwater harvesting
• Ground water recharge
• Efficient demand management
• Using water conservation fixtures
• Waste water reclamation and re-use
• Surface water treatment
Rainwater harvesting
City area: 370sq.km.
Avg. annual rainfall: 2m
Total vol. of rainfall: 740000 million liter
Concrete roof area available: 74.58 sq.km.
Yearly total vol. of rain water: 149140 million liter
If 60% of this water can be collected, then more than 200 MLD
water will be available for household use and artificial ground
water recharge.
Rainwater harvesting
Measures to be taken:
• Harvest roof top rain water and use it for
domestic non potable water requirements
• Excess rain water can be recharged in to
nearby underground water bodies such as
bore well or open wells to replenish the
ground water
Metering, Pricing & Taxing
Measures to be taken:
• Monitor the water consumption, install water meters
on down take line.
• Illegal connections must be blocked and system loss
should be reduced.
• Billing and collection of water and sewerage bills
should be computerized
Waste water re-use
Measures to be taken:
• Provide grey water treatment and use
recycled water for gardening / toilet flushing/
car washing
• Provide separate plumbing down take lines
from the source so that designated treatment
can be planned separately.
• Grey water to be collected and treated
separately and thus to recycled back for
toilet flushing or gardening.
Surface water treatment
Measures to be taken:
• Surface water intake points have to be
identified effectively.
• A second intake upstream from the
Saidabad intake at the Lakhya River can
serve the area east of Uttara (Newly
developing northern part of Dhaka city).
• Intake at the Meghna river (One of the large
rivers) near Baidyer bazar can server the
people of Narayanganj.
Pilot survey for piped water supply system
Upazilla: Bandar.
District: Naraynganj.
Name of the
Village
Total nos. of
households
Population Total Population
Male Female
Ali Nagar 182 648 570 1218
Gharmora 310 1226 1054 2280
Char
Gharmora
309 972 870 1842
Total 801 2846 2494 5340
Distribution of Households Income Source
Name of the
village
Farmers Service Business R/V
Pullar
Day
Labour
Others Total
Gharmora 15 119 149 4 4 19 310
Chor Gharmora 30 102 122 10 45 0 309
Alinagar 2 66 55 2 57 0 182
Total 47 287 326 16 106 19 801
Income group Status Income Range Nos. of HH
G-1 Very poor Less than TK. 1,000 5
G-2 Poor TK.1,000 to TK. 3,000 39
G-3 Medium income group TK.3,001 to TK. 5,000 178
G-4 Rich TK.5,001 to TK. 10,000 450
G-5 Affluent income group Above TK. 10,000 129