Climate change and variability are matter of concerns of human beings throughout the world. The recurring droughts and floods are seriously threatening the livelihood of billions of people who depend on agriculture for most of their needs. The global economy is being adversely affected due to extreme events such as droughts, floods, cold and heat waves, forest fires, landslides etc. The natural calamities like earthquakes, tsunamis, volcanic eruptions etc. though not directly related to weather disaster but may change chemical composition of the atmosphere which, in turn, lead to weather-related disasters. Among the greenhouse gases, carbon dioxide is the pre-dominant gas leading to global warming as it traps long wave radiation and emits the same back to the earth surface. The global warming is nothing but heating of surface atmosphere due to emission of greenhouse gases, thus, increasing global atmospheric temperature over a long period of time