The gradual increase in the overall temperature of Earth, its atmosphere and the surface is often termed as global warming. This is mainly caused due to the greenhouse effect where the various component of sunlight (such as ultraviolet rays) are allowed to pass through the ozone instead of being trapped and these are absorbed by the surface of earth instead of being reflected back.
The greenhouse effect is caused primarily by the excessive release of greenhouse cases such as carbon dioxide which is the leasing contributor in global warming. It does so by damaging the ozone layer and creating porous holes for the components to pass instead of being entrapped. The major sources of production of such greenhouse gas are: Domestic refrigeration and air conditioning systems, industrial smoke and wastes, smoke and emission from the automobile exhaust and various other causes.
It has been estimated that by the end of 2050, almost 85% of the planet will be submerged under water as the global warming has caused majority of the glaciers at north and South Pole to melt which causes a gradual increase in sea level and imposes a threat to the low line land areas especially. The Tsunami that hit india and Sri lanka and many such catastrophic events are attributed to global warming and the issue needs immediate attention and solution from the mankind or else it shall be too late to preserve the existence of life.