Basic Civil Engineering first year Notes- Chapter 4 Building.pptx
Bangladesh Climate Vulnerability: Floods and Cyclones
1. Bangladesh Climate Vulnerability: Floods and
Cyclones
BANGLADESH CENTRE FOR ADVANCED STUDIES
House 10, Road 16A, Gulshan 1, Dhaka 1212, Bangladesh
Phone: 8818214-7, 9851234, 9852904; Fax: 9851417
Website: www.bcas.net
Dr. Atiq Rahman
Executive Director: Bangladesh Centre for Advanced Studies (BCAS)
Founding Chairman: Climate Action Network – South Asia (CANSA)
Visiting Professor: Fletcher School of Law and Diplomacy , Tufts University and Harvard
University, Boston, MA, USA
IFPRI 2020 Conference on Building Resilience for Food and
Nutrition Security
Date: 15-17 May, 2014
Addis Ababa, Ethiopia
2. Outline of the presentation
1. Bangladesh: Most vulnerable country
2. Extreme Events: Climate Impacts
3. Cyclones: A Case Study
4. Floods: A Case Study
5. Responses: By Communities
3. CLIMATE CHANGE CASE STUDY: BANGLADESH
VULNERABILITY
1. Sea Level Rise
2. Cyclone (Intensity & Frequency)
3. Deeper Penetration of Saline Water
4. Erratic Rainfall
5. Flood (Intensity & Frequency)
6. Drought
7. River Bank Erosion
8. Health
9. Food Security
10. Water Security
11. Land slide in CHT
12. Migration
4. Relief Map of South Asia
http://www.flickr.com/photos/ocean_of_stars/2785428699/sizes/o/in/photostream/
Nepal
India
Myanmar
Pakistan
5. Bangladesh occupies a unique geographic location spanning a stretch of land between
the mighty Himalayan mountain chain on the north and the open ocean on the south. It
is virtually the only drainage outlet for a vast river basin complex made up of the Ganges,
Brahmaputra and the Meghna and their network.
6. The Complex River Systems
1. Unique geographical location
2. Dominance of flood plain
3. Himalayan drainage eco-system
Water Tower
Water Sink
7. The variability of onset, breaks and duration of the summer monsoon have enormous
affects on water resources, agriculture, economics, ecosystems, and human mortality
throughout South Asia and Bangladesh as well.
Location of Bangladesh in relation to major river basins in South Asia
9. Earth quake
Tsunami
Volcanic Eruption
Flood & River Erosion
Cyclone
Drought
Land slide
Heat/Cold waves
Sea Level Rise and Salinity
Intrusion
NaturalHazards
ExtremeClimaticEvents
Climate Change Related
Tectonic
Types of hazards
10. How Climate Change Increases Risk
Changes in the magnitude,
coverage and frequency of climatic
extremes
Changes in average climatic
conditions and climate variability,
affecting underlying risk factors
Generates new threats, which a
region may have no or little
experience in dealing with.
10
11. Climatic Extreme Events
Temperature rise and heatwaves in China, Russia,
Mongolia, Korea, Japan, India and South East Asia
Increased and erratic rainfall induced frequent floods
in Bangladesh, India, China and South East Asia
Cyclones and Typhoons in South Asia, Bangladesh,
India, Philippines, Japan and China
11
12. Climatic Extreme Events
Number of recorded
disasters doubled
globally from
approximately 200
to over 400 per year
in the past two
decades
Nine out of 10
disasters are now
climate related
Sea level rise and salinity in South
Asia, Bangladesh, India, Maldives,
Sri Lanka, Indonesia and SEA
Droughts in South Asia including
India and Bangladesh, South East
Asia, China and Mongolia
13. Source: Swiss Re sigma Catastrophe database: Include floods, storms, droughts, forest fires, cold wave & frost, hail and other
Change in Frequency of Hazard Event
13
15. Global cost of weather extreme events is increasing
to a great extent
15
16. Number of houses damaged per million people per year
(using 21 datasets)
Source: Global Assessment Report on Disaster Risk Reduction 2011, UNISDR
16
20. Hazard Class Map
Ranking of multi-hazard maps used for
preparing the risk-index :
Cyclone ( high risk-5, risk-3,wind risk- 1)
Flood (Severely flooded due to major
river floods – 3, flash flood due to major
river-2, other flood-1)
Riverbank erosion(severe erosion-2,
erosion -1)
Drought (very severe drought prone
areas – 2, severe drought-1)
26. Flood Frequency
Flooded
Area
Return period (Years)
2 5 10 20 25 50 100
Area
affected %
20 30 37 43 52 60 70
Last 30
years
5 3 2 2
Last 10
years
3 2 1 1
Inundated Area during Different Floods and Number of Occurrences
in Last 30 Years
For Example: A flood event with return period of 20 years has already
occurred twice during the last 10 years.
27. EXISTING DROUGHT SITUATION,
AND DROUGHT SITUATION IN THE YEARS 2030 & 2075
EXISTING DROUGHT
DROUGHT CLASSES (KHARIF SEASON)
Very Severe Drought
Severe Drought
Moderate Drought
Less Moderate Drought
Slight Drought
Very Slight to Nil
Severe & Moderate
Moderate & Less Moderate
Sunderbans
Forest
ADDITIONAL DROUGHT
PRONE AREAS IN 2030
ADDITIONAL DROUGHT
PRONE AREAS IN 2075
30. Migration
Source: IPCC AR4, 2007
Internal initially
External later
No one wants to leave their land
Global justice: Issues of migration
Human rights: Issues of migration
Migration already happening
Strategic dimension of migration
31.
32. Key Climate Change Stresses and Impacts on
CHT
• Hills support sub-ecosystems
which are rich in species and
biodiversity
• These give livelihood supports
to the hilly people
• Key stresses in CHT
– Temperature rise
– Erratic rainfall
– Extreme events -Flood
and Landslide
35. 1970
1991
2007
Source: DMB Situation Report,2007
• According to ICZMP coastal area includes
19 districts. Among these 16 coastal
districts are considered in present study
• Total area: 42,500 km2
• Total population: 31 million (BBS, 2001)
History of major cyclones
38. • Wind speed will increase around 10%for
one degree Celsius increase in
temperature.
• Frequency and Intensity of cyclone will be
more.
Climate Change Impact on Cyclone
45. Causes
a. Heavy rainfall
b. Heavy siltation of the river bed reduces the water
carrying capacity of the rivers/stream.
c. Blockage in the drains leads to flooding of the area.
d. Landslides blocking the flow of the stream.
e. Construction of dams and reservoirs
f. In areas prone to cyclone, strong winds accompanied
by heavy down pour along with storm surge leads to
flooding.
Flood
51. • Flooding event will increase both in
terms of intensity and frequency
• The average flooding depth will increase
about 0.3 m
• The 50 year return period of flood event
will be a 20 year event
Climate Change Impact on Flooding
52. The Linkage
Climate Change
Global Warming (Anthropogenic)
Temperature Rise
•LST
•SST
Variation in Precipitation Ice Melting and Sea Level Rise
Flood Drought Cyclone and Storm Surge
Loss of Property + Injury + Death
DISASTER
53. Food Security
IPCC estimates that, by 2050, rice production in
Bangladesh could decline by 8 percent and wheat by 32
percent
Decrease production of livestock,
Increase of pest attack
Decrease production of fisheries
54. Development over time in Climate Change Impacted scenario and
Adaptation Achievements
Dividend in climate smart development
Development($)
Climate impacted development loss
Climate smart adaptation benefits
Time (t) years
54