Global warming in simpler terms, is increase in the overall temperature of Globe. When we talk about global level, even a 1 degree temperature increase can cause adverse effect on the environment. Main reason behind global warming is the increase in the greenhouse gases which are, carbon-di-oxide, methane etc. Due to their accumulation, solar heat reaching earth is unable to escape and gets trapped within the surroundings leading to overall increase in the global temperature and ultimately causing global warming.