GLOBAL CLIMATE CHANGE AND ITS GLOBAL CLIMATE CHANGE AND ITS EFFECTS ON HYDROGEOENVIRONMENT EFFECTS ON HYDROGEOENVIRONMENT

OF BANGLADESH COASTAL BELTOF BANGLADESH COASTAL BELT

Prof Dr Muhammad Prof Dr Muhammad QumrulQumrul HassanHassanChairmanChairman

Geology Department, Hydrogeology and Environmental Geology Geology Department, Hydrogeology and Environmental Geology University of DhakaUniversity of Dhaka

Curzon Hall Campus, Dhaka 1000Curzon Hall Campus, Dhaka 1000Email:mqhassan2002@yahoo.com,mqhassan@univdhaka.eduEmail:mqhassan2002@yahoo.com,mqhassan@univdhaka.edu

International Symposium onInternational Symposium onClimate Change and Food Security in South AsiaClimate Change and Food Security in South Asia

August 25August 25--30, 2008, Dhaka, Bangladesh30, 2008, Dhaka, Bangladesh

Global Warming: Who Loses – and Who Wins ?Bangladesh context !

Earth's Surface

Indian Plate Development

South Asia Geology

Our Solar System

TransTrans--Sphere Fluxes of the EarthSphere Fluxes of the EarthAtmosphereAtmosphereHydrosphereHydrosphereLithosphereLithosphereBiosphereBiosphere

Environments

HYDROGEOENVIRONMENT

Continental Margins

No Safe Water >No life> No Society

• W.H. Auden : "Few have died for lack of love, many have died for lack of water".

• Water, indeed, is life. • It sustains the flora and fauna on the earth.• It is the most important to the way of life in all countries

habitants. If it is an Agricultural land then it will the mainstay of livelihood system of the country which depends on water cycle.

• Water resources provide multitude of services like drinking, irrigation, fishery, forestry, navigation, industry and many other consumptive and non-consumptive uses > Ecosystem.

Processing and Development System: Hydrological >Hydro-geological>Environmental aspects

• Conditions of True Water Budget Estimation: • Local and Regional Hydrological Aspects (LRHA)• Local and Regional Hydro-geological Conditions (LRHGeoC)• Local and Global Environmental Balance (LGEB)• Environmental Impact Assessment (EIA)• Environmental Auditing (EA) is closely related to monitoring, norm

and standards. • Environmental Monitor (EM) is the systematic observation of the state

of the environment and, the factors are influencing it. • Environmental Norms (ENs)are reference figures or use rates of

natural resources production unit established for the quality ofenvironment, the volume of waste or per production unit.

• Environmental Standards (ESs) are documents setting rules, guidelines and numeric values defined by the involved parties and regulating activities or results of activities which either have or are likely to have impact on the state of the environment.

Sea-Level Rise

• Bangladesh, one of the world's densely nations is also the country most vulnerable to sea-level rise. The population is already severely affected by storm surges. Catastrophic events in the past have caused damage up to 100 km inland. It is hard to imagine to what extent these catastrophes would be with accelerated sea-level rise.

• Digital terrain modelling techniques have been used to display the Bangladesh scenarios.

• A three dimensional view of the country has been overlaid with the current coastline and major rivers and potential future sea levels at 1,5 meters.

• Since this scenario was calculated in 1989, the expected rate of sea level rise has been modified. At present expected rates, this stage will occur in about 150 years from now.

Delft Hydraulics. (UNEP/Delft 1989)

Retreat of Glacier

Bangladesh Coastal belt

Bangladesh has about 710 km long complex shoreline.

It extends along the Bay of Bengal from the mouth of the Naf River in the

southeast to the mouth of the RaimongalRiver in the southwest.

The coastal morphology of the country is a very complex and dynamic system undergoing continuous changes

as a result of active delta building processes.

With the exception of the hilly region in the east, the entire central and

western part of Bangladesh is drained by the Ganges, the Brahmaputra and the Meghna Rivers, which together have

developed one of the largest deltas of

the world

December 26, 2004Tsunami

Coastal Cities• Coastal cities inundated, farming regions, ocean

currents disrupted, tropical diseases spreading, glaciers melting—an artificial greenhouse effect could generate countless tribulations.

• If Earth’s climate changes meaningfully—there could be broad-based disruption of the global economy unparalleled by any event other than World War II (NAS, 2005).

Bangladesh Climatic Data

• Met-Climatic Data• Atmospheric Pressure• Temperature• Humidity • Wind, Sunshine• Precipitation – Rainfall, etc.,• Evaporation• Evapo-traspiration• Climatic balance: Climatic stress + Climatic

surplus>climatic changes/ climatic shifting etc.,• Agro-Climatic Data

Hydrological Calendar (Hassan, 2001) LTI, Saga, Japan

Higher and Lower Rainfall Months in SW Bangladesh (Hassan, 1994) (less then 1.0mm)

Jan to Feb (2 months)March to Dec (10 months)R510

Jan to May (5 months)June to Dec (7 months)R507

Jan to Apr (4 months)May to Dec (8 months)R504

Data not AvailableR459

Jan to April (4 months)May to Dec (8 months)R456

March to April (2 months)May to Feb (10 months)R454

Lower Rainfall MonthsHigher Rainfall MonthsRainfall St.

Comparison of the Climatic Variables of Jessore and Khulna, SW Bangladesh (Hassan, 1995) DU J Sci.

Note (+ indicates surplus, - indicates stress, 0 no variation)

0 +10 -1

4 48 8

4 58 7

Duration of Wet in monthDry in month

+0.099 +0.223.24 3.423.34 3.65Mean annual evaporation in mm/d

+7.36 + 7.32+0.07 - 0.23

10.81 9.1325.70 26.45

18.17 16.4525.77 26.22

Temp in oCa. Fluctuationb. Mean monthly

+ 163 + 3851652 15571815 1942Rainfall in mm/a

VariationJessore - Khulna

Past (1900-72) Manalo, 1977

Jessore - Khulna

Present (1968-88)Jessore - Khulna

Importance 1. Hydrologic Cycle; Water Resources

Rainfall Distribution in Bangladesh

Why is climate so Important?Why is climate so Important?• Climatic components action with the earth surface:

• Erosion > Cave > Valley > Stream course > River Basin > • Deposition > Land-form >Delta form• Topographical change • Groundwater storage• Change in soil formation• Different types of disaster> Temperature increasing> ice melting Sea

level rise> Tidal flooding> Continental flooding> Upstream flashflooding, Cyclone-storm, Typhone, etc.

Earth's WATER BUDGETEarth's WATER BUDGET

97.5%

2.4%

0.001%

Environmental Factors in Bangladesh Coastal BeltVarious factors, such as:

i) the input huge amount of water and sediment discharge brought by these rivers into the Bay of Bengal,

ii) the interaction between the fluvial and marine processes at the river mouth,

iii) a favourable climatic condition, and iv) the cyclic nature of the delta system, combine to

produce a coastal belt, which is exceptionably rich in agricultural and other renewable resources, like fisheries and forestry.

Under natural conditions, the self-maintaining nature of the delta system ensures continuity of these coastal resources.

Population• Bangladesh is the most densely populated country in

the globe. The country has a population of 140 million with a corresponding population density of more than 900 per square kilometers.

In addition, a huge population of Bangladesh depends on this system for their survival. However, the overall sustainability of the resources depends largely on the environmental sustainability of the system, which appears to be extremely delicately balanced and fragile.

• The coastal zone of Bangladesh is unique in the sense that it is located at the land-sea interface, and is thought to be ecologically very sensitive. The zone may be described as the transitional area between the two environmental domains – the continental and the marine.

Environmental Domains

• These domains are functionally dependent on each other in several different ways. The coastal zone occupies that part of the land which is influenced by its proximity to the sea and that part of the sea affected by its proximity to the land

Study on Bangladesh Coastal Belt (Hossain et al, 2000)

The main objectives of the present climate change studies are:1) To identify the major environmental issues and important environmental components (IECs) of the coastal areas of Bangladesh.

(2) To work out the methodology to be used to quantify human induced impact on coastal environment and the degree of environmental degradation.

(3) To determine the trend of environmental changes in the coastal areas of Bangladesh and to identify the major forces responsible for causing these changes.

Contd.

(4) To identify major sources of baseline data to be used to compare and to quantify the changes.

(5) To determine the degree of changes in the hydrological and sedimentation patterns introduced by human activities and develop methods to be used to quantify these changes, e.g., changes in rate of sedimentation or subsidence or salinity intrusion, etc. (6) To evaluate how the coastal geomorphology has changed over the last 100 years due to human activities and climate – change effects.

Contd.

(7) To understand the impact of climate-change and human activities on the coastal ecology including fauna, flora and biodiversity? Are the human induced changes in the physical system mainly responsible for the changes in the ecosystem or other? What will be the best way to examine the changes and to quantify them?

(8) To understand the social and economic impact of human intervention and climate-change effects and on the coastal environment?

(9) To investigate possible means to improve or to stop any further degradation by man-made events of the coastal environment.

• 10) To understand the possible impact of sea level rise on the coastal hydro-geo-environment

Contd.

Our recent field observations (2000-2001) on the hydro-geo-environmental issues of the coastal areas of Bangladesh are considered the following points:

• sedimentation, water logging and drainage congestion, erosion and accretion, subsidence, cyclone, tidal flooding, fisheries, agricultural, deforestation, afforestation, navigation, wetland, biodiversity, health and education.

Climatic Changes Climatic Changes Results: Images Results: Images from the Great from the Great Flood of 1998Flood of 1998

26 August 1998

Climate Changes Climate Changes Results ?Results ?Bangladesh 1998 Bangladesh 1998 FloodFlood

Meghna Basin82,000 sq.km

Brahmaputra Basin552,000 sq.km

Ganges Basin1,087,000 sq.km

B A Y O F B E N G A LB A Y O F B E N G A L

N E P A L

BHUTAN

I N D I A

C H I N A

MYANMAR

BANGLADESH

I N D I A

Bangladesh River System

River System: 24,000 km

Trans-Boundary Flow : 57 rivers

Dhaka Flood 2004

Annual Average Rainfall : 2300 mmCherapunji ( india): 12000-24000 mm

Dhaka Flood 2004

D h a k a o n t h e B u r i g a n g a R i v e r

1 . 0

2 . 0

3 . 0

4 . 0

5 . 0

6 . 0

7 . 0

8 . 0

1 6 - M a y 3 1 - M a y 1 5 - J u n 3 0 - J u n 1 5 - J u l 3 0 - J u l 1 4 - A u g 2 9 - A u g 1 3 - S e p 2 8 - S e p

D a t e

Wat

er L

evel

(mPW

D)

1 9 9 8

1 9 8 8

2 0 0 4

Dhaka Flooding in 1988 and 1998

Surface Water Salinity in Bangladesh Coastal Belt

Soil Salinity Map

Erosion and Accretion Map

Cyclone hits and affected areas

Flooding in 2007 near Ahsulia Saver, Dhaka, Bangladesh (photo by Conny)

Flooding in 2007, Bangladesh (photo by Conny)

Effect of The Cyclone Sidr –Nov 16th 2007, Bangladesh (photo by Conny)

Sundarban Mangrove Forest results from The Big Cyclone Sidr – Nov 16th 2007, Bangladesh (photo by Conny)

Climatic Condition of SW BangladeshTime period 1900-1973-1993

• Present day rainfall is increasing from the previous study whichranges from 1.8 to 256.5 mm/a

• Present day evaporation is decling from the previous study whichranges from 45.79 to 291 mm/a

• Present day temperature is increasing from the previous study which ranges from 0.11 to 0.77oC

• Present day relative humidity is increasing from the previous which ranges from 3.0 to 10.41%

• Present day sunshine hours is declining from the previous which ranges from 0.31 to 1.35.

• Present day windspeed at Jessore is increasing up to 0.75 Knots from the previous while at Khulna it has not changed.

Food Availability etc..

• Change in water quality and quality due to climate change are expected to affect food availability, stability, access and utilization.

• This is expected to lead to decreased food security and increased vulnerability of poor rural farmers, especially in the arid and semi-arid tropics and Asia and African mega-deltas (IPCC W Gr II, June 2008).

Climatic Observation on the SW Bangladesh

• From the above scientific discussion, it can be concluded that the area has undergone some climatic changes in its variables. The Ganges Delta Region of southwest Bangladesh is a transient zone from the tropical to the subtropical and landing area of the monsoon from the Indian Ocean, where strong gradient and variance in the surface air is observed.

• Present research on the different parts of the World has also been revealing many basis features of the climatic changes of the past. This is the main source of basic for projections of the future climate.

• The relevant organizations of Bangladesh should investigate the issue of Global Climatic Changeimmediately in the whole area of Bangladesh.

Target for Planning

Agro-climatic map and hydrological calendar in Upazila level for sustainable agricultural development

• Estimated local water budget (LWB)• Integrated water management plan (IWMP) • Estimated local Environmental Impact

Assessment (EIA)

Global Warming: Greenhouse effect

- Earths temperature has risen by 0.5oC over the past century,-Sea level - a 20cm rise by 2030 is expected to result from glacial melting and from the thermal expansion of the oceans as water temperatures rise.-Agriculture and forestry, crop failure and famine will ensure,-Water resources, global rainfall pattern will change and the water management strategies of different regions will need to adopt.-Terrestrial ecosystems – many plants and animals species will have problems adapting,-Human health – over the long-term there is likely to be an increase in the spread of certain diseases, malaria, for example,-Ref: www.ecocentre.org.uk/global -warming.html

Asia faces floods, drought, disease: UN climate reportBRUSSELS - Asia faces a heightened risk of flooding, severe water shortages, infectious disease and hunger from global warming this century, the UN's top climate panel.

The region is confronted by a 90-per cent likelihood that more than a billion of its people will be "adversely affected" by the impacts of global warming by the 2050s, the UN's Intergovernmental Panel on Climate Change (IPCC) said. Its estimates, in a major report unveiled in Brussels, say the magnitude of climate-change effects will vary according to the size of the world's population, energy use and the level of greenhouse gases in the atmosphere, which determines the rise in global temperature. But under any scenario, the world's most populous region will be badly hit. Here are the major findings: -- 120 million to 1.2 billion people in Asia will experience increased water stress by 2020, and 185 to 981 million by 2050.

cont...next slide>>>>>>>>>>>>>>>>>>

Bangladesh, China and Vietnam - Cereal yields in South Asia could drop in some areas by up to 30 per cent by 2050. -- Even modest rises in sea levels will cause flooding and economic

disruption in densely-populated mega-deltas, such as the mouths of the Yangtze in China, the Red River in China and Vietnam, and the Ganges-Brahmaputra delta in low-lying Bangladesh. -- Cholera and malaria could increase, thanks to flooding and a wider habitat range for mosquitoes. -- In the Himalayas, glaciers less than four kilometres (2.5 miles) long will disappear entirely if average global temperatures rise by 3 degrees Celsius (5.4 Fahrenheit). This will initially cause increased flooding and mudslides followed by an eventual decrease in flow in rivers that are glacier-fed. -- Per capita water availability in India will drop from around 1,900 cubic metre (66,500 cubic feet) currently to 1,000 cu. metres (35,000 cu. ft.) by 2025. -- Some 30 per cent of Asian coral reefs, which sustain a large per centage of marine life, are expected to be lost in the next 30 years, although this will occur as a result of multiple stresses and not just climate change. (Document: Working Group II contribution to the Intergovernmental Panel on Climate Change, Fourth Assessment Report). By Agence France-Presse

Climate May Bring Big Changes for United States

• The consequences of global climate change on the United States may be dramatic – both bad and good.

• Greenhouse warming is likely to bring temperature increases of 5-10°F to the United States, considerably more than the worldwide average warming in the next 100 years.

• A recent key draft report spells out potential consequences of climate change for each major region in the United States. The study gets down to cases and gives climate change a face. Depending on where you live, global warming may mean flood or drought (or both). It may mean bumper crops but lower prices for farmers. It may mean destruction of coastal wetlands in the Chesapeake Bay, or the rebuilding of human structures built on Alaskan permafrost

Major Findings in the USA

If global climate change unfolds as expected from the standard computer-modeled scenarios, then, the assessment concludes, the following impacts can be expected:

1. Temperature in the United States will rise 5-10°F by 2100. 2. Effects of climate change will vary dramatically – even paradoxically – from region to region. 3. Certain ecosystems are especially vulnerable to climate change and some may be destroyed, such

as coastal barrier islands and Rocky Mountain alpine meadows. 4. Water will be an issue in every region, but impacts will vary. Increased precipitation will bring more

flooding to some areas. Others will suffer more drought because higher temperatures will increase evaporation. Changes in snow-pack will affect the West, Pacific Northwest, and Alaska.

5. Climate change will dramatically shift which crops can grow where, but farmers will often be able to adapt. Overall, agricultural production is likely to increase over the next few decades, but the gains will not be uniform and some changes may bring lower prices and hardships for some farmers.

6. The “fertilizer” effect of increased atmospheric CO2 will mean more timber growth in the first few decades. But in the longer term, climate-worsened fire, insects, drought, and disease could lower forest productivity, and will cause northward “migration” of forest types.

7. Rising sea level and possible changes in storm frequency and intensity are likely to speed coastal erosion and threaten buildings, roads, power lines and other infrastructure in low-lying coastal areas.

( Ref: Environmental Health Center, USA 2000)

Bangladesh Tea Plants in Sylhet

• Many thanks for attention during my lecture time

International Symposium on Climate Change and Food Security in South AsiaAugust 25-30, Dhaka, Bangladesh