Global warming is one of the most serious global environmental issues. Certain gases like carbon dioxide, nitrogen oxide, methane and chlorofluorocarbons present in atmosphere along with water vapours absorbs the sun’s radiation and will not let it escape. Consequently the atmosphere gets warmed up and causes global warming. A very small quantity of chlorofluorocarbons (CFCs) emitted to the atmosphere from leaking refrigerators or some industrial processes have resulted in degradation of the ozone layer. Basic activities like cattle raising and paddy planting also emit methane nitrous oxide and other GHG, s. Very slow, almost imperceptible rise of about 4-5 degree Celsius in the global temperature has occurred in the past 20000 years. A rise of about 0.3 degree Celsius to 0.8 degree Celsius was recorded during the last century alone which is remarkable. Some human activities as energy production and its use, intensive agriculture, maintenance of huge livestocks population, land use modification and industrial production are responsible for global warming. Global sea level could rise by more than 20 feet devastating coastal areas worldwide. A number of people will die from the spread of tropical diseases. Heat waves, droughts and wildfires will be more frequent. Tropical cyclones will likely become more intense, with larger peak wind speeds and more heavy precipitation associated with ongoing increases of tropical sea surface temperatures. The present paper is an attempt to analyze global warming and how it changes our climate and human beings.