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Akm Saiful Islam. WFM 6311: Climate Change Risk Management. Lecture-1: Module-1 &2 Climate System, Global Warming, Green House gases. Institute of Water and Flood Management (IWFM) Bangladesh University of Engineering and Technology (BUET). December, 2012. Module-1.
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Akm Saiful Islam WFM 6311: Climate Change Risk Management Lecture-1: Module-1 &2 Climate System, Global Warming, Green House gases Institute of Water and Flood Management (IWFM) Bangladesh University of Engineering and Technology (BUET) December, 2012
Module-1 • Climate System and Hydrologic cycle • Atmosphere • Cryosphere: Sea, Ice sheet, Glacier • Hydrosphere: River, Lakes, ocean interactions • Hydrologic Cycle • Biosphere and Ecosystem
Module-2 • Climate variability and climate change. • Global warming and green house gases • Historic aspects of global climate change • Climate change in South Asian context: Case study
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%
Green house gases • CO2 and some other minor gases • Absorb some of the thermal radiation leaving the surface of the earth. • 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.
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, …)
Ice melting • Images gathered from the Defense Meteorological Satellite Program of NASA show the minimum Arctic sea ice concentration 1979 (left) and 2003 (right). 2003 1979
Emission of Green house gases • Emission of Co2 Bangladesh < 0.2 ton/yr