Weather and Climate - Divecha Centre for Climate Change

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Climate Change: Bangladesh Perspective
Arjumand Habib, Director
Bangladesh Meteorological Department
Dhaka, Bangladesh
1. Introduction
Geographically Bangladesh is in
the highly disaster prone area of
deltaic
origin
of
GangesBrahmaputra
Basin
having
Himalayas in the north and Bay
of Bengal in the south with a
complex coastal configuration
and shallow bathymetry.
It is an agro-based tropical
country, climate is southwest
monsoon
driven
with
a
significant variation in rainfall
and temperature over the year.
Recorded
tropical
cyclone
devastation in Bangladesh is the
worst in the world. About 80% of
the land is flood prone, 90%
discharge
of
GangesBrahmaputra-Meghna basin is
through
Bangladesh
during
monsoon.
Position of Bangladesh in the World Map and in
the Asia Map
1. Introduction continue……….
•
Other than tropical cyclone, extreme events like thunderstorms, tornadoes and
localized heavy rainfall causing causalities and loss which is almost close to
that of one cyclone every year.
•
With this climate change impact would adversely affect the existing
vulnerability more.
•
As a least developed country with highest population density (Total area of
Bangladesh 143,999 square kilometers; according to the latest census report
published in July 2011 population density is 964 per square kilometer; the rate
of population growth is 1.34 per year and total number population increased
during last 10 years is about 1.8 crore), inadequate infrastructure for
protection, lack of institutional capacity for taking proper adaptation and
mitigation and because of its climate sensitive economy, particularly agriculture
will face enormous human suffering in terms of food, water, shelter, health and
overall livelihood.
•
Expansion and strengthening of capacity in generation and utilization of
emerging climate information and provision of effective end-to-end early
warning are the urgent need to support Government, private sectors, NGO’s
and public for disaster risk reduction and for adaptation and mitigation of
climate change impact.
2.1 Climate of Bangladesh
Bangladesh is a subtropical monsoon climate characterized by wide
seasonal variations in rainfall, moderately warm temperatures, and
high humidity. Based on the analysis of pressure, rainfall and
temperature, the climate of this country can be described under
the following four seasons:
a. Winter or Northeast Monsoon: This season comprises of
December, January and February; mean temperature is 18-21C
and average rainfall is about 1.5% of the total annual rainfall.
b. Summer or Pre-Monsoon: This season consists of March, April
and May; average rain fall is 17% and mean temperature is 2330C and average rainfall is 17% .
c. Southwest Monsoon or Monsoon: This season consists of June,
July, August and September; average rain fall of this season is
about 72.5% of the total annual rainfall.
d. Autumn or Post-Monsoon: This season consists of October and
November; average rainfall receives in this season is about 9%.
3. Trend of Change
3.1 Temperature: Temperature trends during last 60 years
(1950-2010) based on observed data of BMD, minimum
temperature and maximum temperature both have a tendency
to increase, minimum more making average day temperature
to follow rising trends as given in Fig. 1 and Fig. 2.
31.0
22.0
y = 0.0092x + 30.234
R2 = 0.2235
30.5
30.0
29.5
21.8
Minimum Temperature(°C)
Maximum Temperature (°C)
31.5
21.6
y = 0.0107x + 20.677
R2 = 0.3359
21.4
21.2
21.0
20.8
20.6
20.4
20.2
Fig: 1: Temporal variation of
annual maximum temperature of
Bangladesh during 1950-2010
1950
1952
1954
1956
1958
1960
1962
1964
1966
1968
1970
1972
1974
1976
1978
1980
1982
1984
1986
1988
1990
1992
1994
1996
1998
2000
2002
2004
2006
2008
2010
20.0
1950
1952
1954
1956
1958
1960
1962
1964
1966
1968
1970
1972
1974
1976
1978
1980
1982
1984
1986
1988
1990
1992
1994
1996
1998
2000
2002
2004
2006
2008
2010
29.0
Fig: 2: Temporal variation of
annual minimum temperature of
Bangladesh during 1950-2010
3.2 Rainfall:
Average rainfall during last 60 years (1950-2010) has a
positive trend with a slight decrease in monsoon season.
3000
20
y = -0.0616x - 5.1577
2800
R2 = 0.0082
10
2600
Rainfall Deviation (%)
2200
2000
1800
1600
1400
0
-10
-20
y = 1.048x + 2224.9
R2 = 0.0043
-30
1200
-40
Fig. 3: Temporal variation of annual
rainfall of Bangladesh during 19502010
1951
1953
1955
1957
1959
1961
1963
1965
1967
1969
1971
1973
1975
1977
1979
1981
1983
1985
1987
1989
1991
1993
1995
1997
1999
2001
2003
2005
2007
2009
1000
1951
1953
1955
1957
1959
1961
1963
1965
1967
1969
1971
1973
1975
1977
1979
1981
1983
1985
1987
1989
1991
1993
1995
1997
1999
2001
2003
2005
2007
2009
Rainfall (mm)
2400
Fig. 4: Inter-annual variation of
monsoon rainfall in Bangladesh
during 1951-2010
3. Trend of Change Continue ………..
 Under a collaborative research between SAARC Meteorological
Centre (SMRC) and Nagoya University on the ‘Understanding the
rainfall climatology and detection of extreme weather events in
SAARC region’ has done in two phases.
 For rainfall climatology Tropical Rainfall Measuring Mission (TRMM)
data sets and for generation of extreme events RegCM (Regional
Climate Model) have been used for Bangladesh and the model
simulated events are compared with BMD’s observed data sets.
 Increasing rate of wet days is high in the NE and SE regions of
Bangladesh. Regarding temperature both maximum and minimum
have a rising trends, minimum more over maximum, maximum more
or less stable.
 So both the analysis shows the signature of Global Warming.
3.3 Extreme events
 Tropical cyclone intensity analysis shows that since
1876 onward particularly in the last 20 years frequency
and the intensity of cyclone more than 200 km/hour ha an
increasing trend.
 Also other extreme events like heavy rainfall within
short scale of time causing flash flood in pre-monsoon
period are increasing and added extra pressure on
monsoon flooding especially in urban area drainage
congestion, prolonged water logging and landslides in
the hilly region and also accelerate river erosion.
Fig. 5: Intense Cyclones
(wind speed >200 Km/h)
over Bay of Bengal
during 1876 - 2010
Fig. 6: Intense Cyclones
(wind speed >200 Km/h)
over Bay of Bengal
during 1950 - 2010
3.3 Extreme events continue……
During 1876 – 1964 there was only one intense cyclone
(wind speed more than 200 Km/h) over North Bay of
Bengal but in next 45 years (1965 – 2010) it was 9.
 From 1950 to 1990 intense cyclones were only two but
during next 20 years (1991-2010) it was 7.
3.4 Rainfall Intensity
Pre-monsoon season: Frequency of heavy rainfall are
increasing in March (+0.0048/year) and April (+0.0061/year)
but significant increasing trend (0.0258/year) is observed in
May. Therefore, heavy rainfall during monsoon season has
considerable increasing trend (+0.0258/year) which means
extreme weather is increasing.
12
Frequency of Heavy Rainfall
10
y = 0.0366x - 66.459
R2 = 0.0789
8
6
4
2
1950
1952
1954
1956
1958
1960
1962
1964
1966
1968
1970
1972
1974
1976
1978
1980
1982
1984
1986
1988
1990
1992
1994
1996
1998
2000
2002
2004
2006
2008
2010
0
Fig. 7: Temporal variation of Heavy Rainfall of Bangladesh in Pre-monsoon
Season during 1950-2010
3.4 Rainfall Intensity continue ………
Monsoon Season: Frequency of heavy rainfall are increasing in June
(+0.0006/year), July (+0.0161/year) and September (+0.0081/year) but
decreasing in August (-0.0025/year). Therefore, heavy rainfall during
monsoon season has also considerable increasing trend (+0.0053/year)
which means extreme weather is increasing.
6.5
Frequency of Heavy Rainfall
6
5.5
y = 0.0053x - 5.5381
R2 = 0.0356
5
4.5
4
3.5
1950
1952
1954
1956
1958
1960
1962
1964
1966
1968
1970
1972
1974
1976
1978
1980
1982
1984
1986
1988
1990
1992
1994
1996
1998
2000
2002
2004
2006
2008
2010
3
Fig. 8: Temporal variation of Heavy Rainfall of Bangladesh in Monsoon
Season during 1950-2010
3.5 Example of extreme events:
a. Heavy Rainfall events in Dhaka on 14 August 2004 and
27 July 2009
 Dhaka (city area) experienced 341 mm rainfall on 14 August
2004 and 333 mm rain on 27 July 2009 in 24 hours.
Consequences of these heavy rainfalls are:
• Most of the educational institutions were closed.
• Life and business came to a halt.
• Public transport services collapsed.
• Slum dwellers lost most of their belongings.
• Rain played havoc in the electricity supply creating power
outage.
b. Landslide on 11 June 2007 at Chittagong
 Heavy rainfall resulted in a landslide in Chittagong,
Bangladesh on 11 June 2007,
• killing 124 people and destroying houses,
• roads and embankments, as well as
• disrupting electricity, gas lines and
• communication facilities.
 According to the Bangladesh Meteorological Department
(BMD) rainfall measured on 11 June was 425 mm within 24
hours at Chittagong city area which is the heaviest in last 25
years.
3.6 Regional trends
• It is well recognized in both the scientific and negotiating
community that Bangladesh would be one of the most
adversely affected countries to climate change.
• According to the Fourth Assessment Report of WMO/UNEP
Intergovernmental Panel on Climate Change (IPCC) released
in 2007, the future projection of climate change indicates that
south Asia is very likely to warm up during this century. Crop
yields may decrease by 30% in the region by the mid-21st
century and considering the influence of population growth, the
risk of hunger is projected to remain very high.
• Other predicted impacts of climate change include inundation
of arable land, salinity intrusion, droughts, reduced fresh water,
availability and persistence of transboundary pests and
diseases.
3.7 Climate Change risks
• All components of climate risk e.g. natural hazards and
extreme weather events, impacts of climate change,
exposure, vulnerabilities and low adaptive capacity all are
visibly existent and seriously exposed because of highest
density of population, their level of poverty, low adaptive
capacity and natural resource dependent economyparticularly agriculture, considering all these Bangladesh will
face enormous human sufferings in terms of food, water,
shelter, health and overall livelihood maintenance unless
proper measures are taken in time.
• Expansion and strengthening of capacity in generation and
utilization of the emerging climate information and provision of
effective early warning is the urgent need to support the
Government and people for taking proper measure for
sustainable environment and socio-economic development.
3.8 Government’s Climate Change Strategy and Action
Plan:
 Climate change strategy and action plan of Bangladesh has
been drawn on the four building blocks of the Bali Action Planadaptation to climate change, mitigation, technology transfer
and adequate and timely flow of funds within a framework of
food, energy, water and livelihoods security for all.
 It is a part of overall development strategy of the country.
The climate change constraints and opportunities are being
integrated into the overall development strategy of the country.
The climate change constraints and opportunities are being
integrated into the overall plan and programme involving all
sectors.
 The National Climate Change Action Plan is built on the
following six pillars:
3.8 Government’s Climate Change Strategy and Action
Plan: Continue ……..
a. Food security, social protection and health to ensure that the
poorest and most vulnerable in society including women and
children, are protected from climate change and that all
programmes focus on the needs of this group for food security,
safe housing, employment and access to basic services including
health.
b. Comprehensive disaster management to further strengthen the
countries already proven Disaster Management System to deal
with increasingly frequent and severe natural calamities.
c. Infrastructure to ensure that existing assets (e.g. coastal and river
embankments) are well maintained and fit for purpose and that
urgently needed infrastructure (e.g. cyclone shelter and urban
drainage) is put in place to deal with likely impacts of climate
change.
3.8 Government’s Climate Change Strategy and Action
Plan: Continue ……..
d. Research and knowledge management to predict the likely scale
and timing of climate change impacts on different sectors of the
economy and socio-economic groups to underpin future
investment strategies; and to ensure that Bangladesh is a
network into the latest global thinking on science and best
practices of climate change management.
e. Mitigation and low carbon development to evolve low carbon
development options and implement these as the country’s
economy grows over the coming decades and the demand for
energy increases.
f. Capacity building and institutional strengthening to enhance the
capacity of Government ministries and agencies, civil society
and the private sector to meet the challenge of climate change
and mainstream them as a part of development action.
4. Measures taken for proper applications of weather and
climate in disaster risk reduction and adaptation and
mitigation of climate change:
Weather and climate information and an effective early
warning system are the key elements for addressing climate
change and reducing natural disaster risk.
4.1 Mandate of BMD
BMD is mandated to observe and monitor the weather and
climate systems and issue of forecasts and warnings for all
sorts of operations pertaining to Aviation, Maritime, Inland
Water Ways and advisories to the Disaster Management
Bureau (DMB) and Relief Ministry in managing all types of
natural disasters and its application in social and economic
planning.
4. 2 Efforts for Disaster Risk Reduction
For disaster risk reduction the following are the four operation
components for a successful of an end-to-end early warning
system:
• Generation of reliable and timely warnings
• Quick and reliable dissemination to the targeted people and
area
• Good governance and all types of physical protections
• People’s sufficient awareness and perception about the
content of the warning message and their resilient to sustain
disaster.
Fig. 9: Variation of GDP growth rate of Bangladesh under the influence
of natural disasters.
Efforts for Disaster Risk Reduction continue…………
To execute the above perspectives, in the operation of an
end-to-end early warning system the Government has made
paradigm shift in policy and governance by shifting from the
concept of relief and rehabilitation to overall disaster risk
management.
Bangladesh has a long history of coping with major disasters.
The Government of Bangladesh and people have a wealth of
experience in preparing for, and responding to disaster
events. In recent years, Bangladesh has been increasingly
recognized as a leader in adopting a more holistic approach
to risk reduction.
Efforts for Disaster Risk Reduction continue…………
200000
During the last 38 years BMD has made significant improvement in
cyclone forecasting and warnings as well as in the timely prediction of
other severe weather phenomena, thereby contributing directly to the
reduction of losses. The gradual reduction of death tolls for tropical
cyclone is shown in figure below:
202500
195000
187500
180000
172500
165000
200000
200000
138882
157500
150000
142500
135000
127500
120000
138882
150000
112500
105000
97500
90000
82500
75000
100000
50000
3363
Cy_2007
Cy_2007
2
Cy_2002
Fig. 10: Causalities along with recorded
cyclones in Bangladesh during 1970-2009
Cy_1991
3
Cy_2000
190
14
Cy_1998
Cy_2009
78
155
Cy_1997
188
Cy_1994
Cy_1991
Cy_1997
6133
Cy_1988
4264
Cy_1985
43
300
Cy_1983
Cy_1983
Cy_1981
Cy_1974
Cy_1970
20
22500
15000
7500
0
72
0
3363
Cy_1970
67500
60000
52500
45000
37500
30000
Fig. 11: Trend of reduction of causalities during
similar intensity cyclones in Bangladesh
4.3 Government initiatives for the
Meteorological Service in Bangladesh
improvement
of
• To contain the climate change impact, natural disaster risks and
keeping environment for sustainable economic development, overall
capacity enhancement of Bangladesh Meteorological Department
(BMD) in the provision of effective early warning system for extreme
events and proper climate services is extremely important.
• In the face of increasing extreme events and the vulnerability of
climate change, demands for such accurate forecasts/warnings,
more precise application of climate data and information based on
local climate scenario development are increasing.
• Also, to maintain the food security and sustainable socio-economic
development, capacity for seasonal climate forecast for agriculture
and climate scenario development in local perspective for proper
adaptation and mitigation of climate change impact are very
important for BMD.
For overall capacity enhancement of BMD in forecasting along
with institutional up-gradation, the following initiatives are
taken:
Institutional up-gradation: Quality performance is the most
important component for delivery of quality service. In terms of
technological development, may initiatives have been undertaken
at the moment to develop the infrastructural facilities and human
capacity in BMD.
But to uphold the efforts of sustainable development in the
meteorological service, it is imperative that quality human
resources be integrated with the system.
For upholding BMD’s mandate in new perspective of climate change
and disaster risk reduction efforts of Government, a proposal has
been submitted to the Government for induction of quality
manpower along with institutional expansion for operation and
maintenance of Numerical Weather Prediction (NWP), climate
modeling, seasonal forecasting and more accurate and timely
early warning system.
Infrastructural development
BMD has taken many initiatives to modernize the existing
weather and climate observatories, establishing new
observatories, introduction of sophisticated Radar and
Communication Systems, capacity building for Numerical
Weather Prediction (NWP) System, downscaling capacity for
climate modeling and up-gradation of storm-surge modeling
system. As such the following projects have been taken
during the last three years:
a. ‘Improvement of Meteorological Radar System at Cox’s Bazar and
Khepupara’
b. ‘Establishment of Meteorological Radar System at Moulvibazar’
c. ‘Establishment of 1st Class Observatory at Five Places of
Bangladesh”
Infrastructural development Continue …….
• ‘Up-gradation of Agro-meteorologiacl Services’
• ‘Development of Human Capacity on Operation of Weather
Analysis & Forecasting’
• ‘Preparation of Wind Map of Coastal Areas/Feasible Areas of
Bangladesh for Assessing Power Generation Potential’
• ‘Improvement & Relocation of Dhaka Meteorological Radar
System for operation in aviation and Riverine Sectors and
Protection of Urban System against National Disasters’
• ‘Numerical Weather Prediction System (2nd Phase)’
• ‘Up-gradation of 35 surface observatories through Establishment
of Automatic Meteorological Observing System & Wind Profilers’
• ‘Collaborating with International Centre for Theoretical Physics
(ICTP), Italy, Beijing Climate Centre (BCC), China and South
Asian Climate Outlook Forum (SASCOF)
Infrastructural development Continue …….
k. Training programme on Storm Surge Modeling with expertise support
from Japan Meteorological Agency (JMA) and sponsored financially by
Regional Integrated Multi-hazard Early Warning System (RIMES) has
been arranged and in future we have a plan with WMO through Coastal
Inundation Forecasting Demonstration Project (CIFDP) in Bangladesh
to integrate Storm Surge Model with Inundation Model to give local
Specific surge height and inundation for taking better preparedness and
local level.
l. Global Framework for Climate Services (GFCS) is particularly meant
for facilitation the Governments in taking proper adaptation for the
introduction of an end-to-end multi-sectoral service delivery system
based on climate prediction utilizing national, regional and
internationally collected weather and climate data. Furthermore, for
effective utilization of GFCS opportunities, association with Regional
Climate Centres (RCC’s) and Regional Climate Outlook Forum (RCOF)
are important in achieving the national capacity to downscale and
integrate those into the prediction system.
5. Conclusion
• BMD is at present in a phase of transition; it is modernizing its
observation and communication networks, changing the
forecasting system from subjective to objective method and
training its personnel to adapt to the ongoing change.
• But in the context of climate change BMD needs capacity
enhancement urgently in the field of proper data management,
downscaling capacity with data assimilation for global NWP
products and climate model, tools of interaction to meet sectoral
demands and strengthening the existing linkage with main
stakeholders and users.
• Furthermore, for effective utilization of GFCS opportunities,
association with Regional Climate Centres (RCC’s) and Regional
Climate Outlook Forum (RCOF) are important, prior to achieve
the national capacity to downscale and integrate those into
prediction system.
5. Conclusion continue……….
• Bangladesh by virtue of its being an agro-based country, would be
immensely benefited by accurate and reliable seasonal and multiple
year long range prediction to guide farmers on the best cropping
strategies and securities.
• The recent increase of Government association in the number of
international agreements, declarations, conventions, related to
weather, climate, water and related environmental issues requires
more involvement of meteorological service.
• To make all the efforts fruitful, more international support and
regional co-operation are required in terms of technology transfer,
infrastructure development, capacity building and real time
exchange of data and information which are quite indispensible for
BMD.
Thanks
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