Transcript Introduction to Climate Change

EIA and Mitigation Measures @ Dr. A.K.M. Saiful Islam, IWFM, BUET
Training Course of
Small Scale Water Resources Project (SSWRP-II)
Introduction to Climate Change
Dr. A.K.M. Saiful Islam
Bangladesh University of Engineering and Technology
Climate Systems
• The complicated system consisting of various components,
including the dynamics and composition of the
atmosphere, the ocean, the ice and snow cover, the land
surface and its features, the many mutual interactions
between them, and the large variety of physical, chemical
and biological processes taking place in and among these
components.
• Climate refers to the state of the climate system as a whole,
including a statistical description of its variations.
 Atmosphere
– 78% nitrogen, 21% oxygen, and 1% other gases.
– Carbon dioxide accounts for just 0.03 - 0.04%.
– Water vapor 0 to 2%
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Components of Climate System
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Green house gases
 CO2 and some other minor gases
1. Absorb some of the thermal radiation leaving the surface of the
earth.
2. Emit radiation from much higher and colder levels out to space.
 These radiatively active gases are known as greenhouse
gases.
– They act as a partial blanket for the thermal radiation from the
surface which enables it to be substantially warmer than it would
otherwise be, analogous to the effect of a greenhouse.
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Green house effect
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Green house effect
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Human induced climate variation
 Perturbations of the atmospheric composition – the
enhanced greenhouse effect
 Effect of aerosols:
– direct effect (scattering of incoming solar radiation)
– indirect effect (affecting the radiative properties of clouds)
 Land-use change (agriculture, deforestation,
reforestation, afforestation, urbanisation, traffic, …)
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Increasing trends of CO2
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Human induced changes of green
house gases
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Global temperature and Greenhouse
gases
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Temperature variation past 1,000 years
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Increase of Temperature past 140 year
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Trends of increase of Temperature
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Predicted changes of Temperature
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Trends of Precipitations
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Trends of Seal Surface temperature
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Sea Level Rise
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Impacts of climate change
 Human Health impacts
 Ecosystem Impacts
 Agriculture Impacts
 Water Resources Impacts
 Market Impacts
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Human Health impacts
 Expansion of the areas of potential transmission of
malaria and dengue fever (medium-to-high confidence);
roughly 300 million more people at risk of malaria
 Increased heat-related deaths and illness, affecting
particularly the elderly, sick, and those without access to
air conditioning
 Increased risks to human life, risk of infectious disease
epidemics and many other health risks where floods,
droughts or storms increase in frequency and/or intensity
 Decreased winter deaths in some temperate regions
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Ecosystem Impacts
 Coral death from exposure to 3-4 ºC higher seasonal maximum seasurface temperatures for 6 months or more
 Substantial reduction in glacier and ice-cap volume; tropical glaciers
particularly vulnerable to elimination
 Loss of unique vegetation systems and their endemic species (e.g.
vegetation of Cape region of South Africa and some cloud forests)
 Extensive reduction in Arctic summer sea-ice extent with benefits for
shipping but adverse effects on sea-ice dependent animals (e.g. polar
bears, seals, walrus)
 Coastal wetland loss from sea level rise (up to 10% globally for 20 cm
rise, higher percentages in some areas)
 Increased disturbances of ecosystems by fire and insect pests
 Increase net primary productivity of many mid- and high-latitude forests
 Extinction of some critically-endangered and endangered species
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Agriculture Impacts
 General decrease in cereal crop yields in mid-latitudes
 Decreased crop yields in areas of increased drought
 Food prices increase relative to projections that exclude
climate change
 Decreased cereal crop yields in most tropical and
subtropical regions
 Increased heat stress in livestock and crop damage from
heat waves
 Decreased frost damage for some crops
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Water Resources Impacts
 Decreased water quantity and quality in some areas of
increased drought
 Increased flood damage due to more intense
precipitation events
 Decreased water supply in many water stressed
countries (half-billion people in central Asia, southern
Africa, and countries surrounding the Mediterranean
affected)
 Increased water supply in some other water stressed
countries (e.g. parts of Asia)
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Market Impacts
 Net market sector losses most regions and for global
aggregate
 Increased insurance prices and reduced insurance
availability in response to increased frequency and
intensity of some extreme climate events
 Decreased energy demand for heating buildings in winter
and increased energy demand for cooling buildings in
summer
 Net market sector losses in many developing countries
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Climate change and Bangladesh
 The country is located in the Bengal Basin, a low-lying
very flat delta. About 80 per cent of Bangladesh is
floodplains with very low mean elevation above the sea
level.
 Differences in the elevation between adjoining ridge tops
and depression centers range from
–
–
–
–
less than 1 meter on tidal floodplains,
1 to 3 meters on the main river and estuarine floodplains, and
up to 5 to 6 meters in the Sylhet Basin in the north-east.
Only in the extreme north-west land elevations exceed 30 meters
above the mean sea level.
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Climate change and Bangladesh
 The flat topography makes a significant part of
Bangladesh vulnerable to sea level change. The active
delta and dynamic morphology complicates the reliable
estimation of vulnerability of tidal floodplains to sea level
rise.
 The net sea level rise would result in
– Inundation of coastal land
– Reduced drainage and hence prolonged flooding due to high
backwater.
– Higher precipitation within GBM basin would result in greater
flood magnitude and frequency.
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Emission of CO2 ->who is responsible?
 Per capita emissions of CO2 is less than 0.2 ton annually
in Bangladesh, compared to 1.6 tons in the developing
countries
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