Dr. Syed Hafizur Rahman

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Impact of Himalayan Glacier Melting and Coastal
Region of Bangladesh
Dr. Syed Hafizur Rahman Associate
professor Department of Environmental
Sciences Jahangirnagar University Dhaka,
Bangladesh E-mail hafizsr_at_gmail.com 16 November
2011
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Presentation Outline

• Himalayan Glaciers
• Impact of Climate Change (CC) in Himalaya
• Bangladesh Profile and Coastal Region
• Impact of CC in coastal region of Bangladesh
• Impact of HGM in coastal region of Bangladesh
• Way Forward

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The main Himalayan range runs west to east, from
the Indus river valley to the Brahmaputra river
valley, forming an arc of 2,400 km (1,500 mi)
long, which varies in width from 400 km (250 mi)
in the western Kashmir-Xinjiang region to 150 km
(93 mi) in the eastern Tibet-Arunachal Pradesh
region
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HIMALAYAN THE ROOF OF THE WORLD

• The Himalayas have the largest concentration of
  glaciers outside the polar region.
•  Approximately 15,000 glaciers (covering an area
  of 33,340 sq.km), and 9000 glacial lakes
  throughout Bhutan, Nepal and Pakistan, as well as
  selected river basins in China and India (ICIMOD,
  2007) which store about 12,000 km3 of freshwater.

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Impact of Climate Change (CC) in Himalaya

• Himalayan glaciers are retreating more rapidly
  than anywhere else in the world which is up to
  70 meters (230 feet) per year (Mats Eriksson).
•  resulting in an increase in the number and size
  of glacial lakes and a simultaneous increase in
  the threat of glacial lake outburst floods
  (GLOFs).
•  Temperature on the Tibetan Plateau is
  increasing by 0.3 degrees Celsius each decade
  thats double the worldwide average (Xu Jianchu)

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Impact of Climate Change (CC) in Himalaya

• If the present rate continues, the likelihood of
  them disappearing by the year 2035 and perhaps
  sooner is very high if the Earth keeps warming at
  the current rate (ABC news).
• With the increased glacial melt, the trapped CO2
  will be released into the atmosphere causing
  further environmental damage.
• The change in glacier ice or snowmelt impacts
  water storage and the water yield to downstream
  areas.

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Impact of Climate Change (CC) in Himalaya
Glacier retreat in the Pho Chu sub-basin of
Bhutan The Luggye Glacier retreated by 160m per
year from 1988 to 1993, resulting in a high
growth rate of Lake Luggye Tso. (ICIMOD, 2007)
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Impact of Climate Change (CC) in Himalaya
Glacier retreat in the Pho Chu sub-basin of
Bhutan The Raphsthreng Glacier retreated on
average 35m per year from 1984 to 1998, but from
1988 to 1993 the retreat rate was 60m per year.

(ICIMOD, 2007)
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Bangladesh Profile and Coastal Region
Bangladesh is one of the largest deltas in the
world, formed by a dense network of the
distributaries of the rivers Ganges, Brahmaputra,
and the Meghna, and more than 230 major rivers
and their tributaries and distributaries. The
total land area is 147, 570 sq km and consists
mostly of low, flat land.
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Bangladesh Profile and Coastal Region

• Bangladesh has a population of 142.319 million
  people with an average population density of 964
  inhabitants per square kilometer (2011)
• Bangladesh is predominantly agricultural, with
  two thirds of the population engaged in farming
  activities

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Map of the combined drainage basins of the
Brahmaputra, Ganges, and Meghna
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Bangladesh Profile and Coastal Region

• In terms of climate,
• Bangladesh is characterized by high temperatures,
  heavy rainfall, high humidity, and fairly marked
  seasonal variations. Although over half of
  Bangladesh is north of the Tropics, the climate
  is characterized as tropical for most of the year
  because of the effect of the Himalayan mountain
  chain, with a warm, almost uniformly humid
  climate throughout most of the year. There are
  three main seasons in Bangladesh
• i. A hot summer season,
• ii. A hot and humid monsoon season,
• iii. A cooler and drier winter.
• (Huq and Ayers, 2008)

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Coastal Region of Bangladesh

The physical geography of Bangladesh is varied
and has an area characterized by two distinctive
features a broad deltaic plain subject to
frequent flooding, and a small hilly region
crossed by swiftly flowing rivers The country is
sloping gently from the north to the south,
meeting the Bay of Bengal at the southern
end According to the coastal zone policy (CZP,
2005) of the Government of Bangladesh, 19
districts out of 64 are in the coastal zone
covering a total of 147 sub districts (upazillas)
of the country
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• On the south is a highly irregular deltaic
  coastline of about 580 kilometers, fissured by
  many rivers and streams flowing into the Bay of
  Bengal
• this is the part of the country most threatened
  from any changes in climate system and in turn
  any of the changes in the water balances of the
  river due to the melting of the Himalayan
  glaciers
• About 1,106 km3 of water crosses the borders of
  Bangladesh annually
• Total Rivers 808
• Transboundary Rivers 58

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COASTAL ZONES The coastal zone covers 47,201
square kilometer land area, which is 32 percent
of total landmass of the country (Islam,
2004) Water area covers 370.4 km (200 nautical
miles) from the coastline (UNCLOS, 1982 Article
57), estuaries and the internal river water

• This zone is divided into three parts
• Eastern coastal zone
• Central coastal zone
• Western coastal zone

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Impact of CC in coastal region of Bangladesh

• Coastal areas in Bangladesh are on the front
  line of climate change, directly affected by
  storm surges, drainage congestion, and sea level
  rise.
• Most of Bangladesh is less than ten meters above
  sea level, with almost ten per cent of the
  country below 1 meter, making it extremely
  vulnerable to increasing high tides.
•  With sea levels expected to rise by an average
  of two to three mm per year during the first part
  of this century, the effects on the coastal areas
  will be severe, and include erosion, coastal land
  subsistence, siltation of river estuaries,
  reduced sedimentation, water logging, and
  saltwater intrusion.

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Sea Level Rise
World Bank (2000) has estimated that by the year
2030 and 2050 at least 30 and 50 cm sea level
will rise respectively
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Impact of CC in coastal region of Bangladesh

• The coastal area of Bangladesh and the Bay of
  Bengal are located at the tip of the northern
  Indian Ocean, which is frequently hit by severe
  cyclonic storms, generating long tidal waves that
  are aggravated by the shallow bay.
• Although Bangladesh now has good early warning
  systems and cyclone shelters have been
  constructed along much of the coast,
  infrastructure and livelihoods are still
  threatened and severely affected, hampering
  further development of the coastal areas.
• 30 districts were damaged by cyclone Sidr for
  example, with the 11 districts closest to the
  coast damaged most severely.

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Cyclone and Storm Surge
IPCC (2007) concludes that a 5-10 increase in
intensity (wind-speed) would contribute to
enhanced storm surges and coastal flooding
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Impact of HGM in coastal region of Bangladesh

• If climate change does alter the rainfall pattern
  in the Himalayas, the impacts could be felt in
  the downstream countries-that is, India and
  Bangladesh.
• By and large, dry-season flow in the major
  Himalayan rivers in a given year results from the
  monsoon rainfall of the previous year.
• Catchments in Nepal supply about 70 of the
  dry-season flow of the Ganges River, and
  tributaries of the Brahmaputra River originating
  in Bhutan supply about 15 of the total annual
  flow of that river.

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Impact of HGM in coastal region of Bangladesh

• If climate change disrupts these resources and
  alters mountain hydrological regimes, the effects
  will be felt not only in the mountain core of
  Tropical Asia but also downstream, in countries
  that depend on this water resource.
• The extent of flooding is exacerbated by the
  sediment loads brought by the three major
  Himalayan rivers, coupled with a negligible flow
  gradient, which increases congestion.

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Way Forward

• Although uncertainties about the rate and
  magnitude of climate change and potential impacts
  prevail, but there is no question that climate
  change is gradually and powerfully changing the
  ecological and socioeconomic landscape,
  particularly in relation to water
• Implementation of international and national
  initiatives and policy to build community
  resilience
• In transboundary water sharing issues, Joint
  watershed management concept would be a
  sustainable approach to reduce climate change
  vulnerabilities and its impacts on common water
  resources

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Thank you for Patience Hearing