Concentration of green house gases is increasing due to

The greenhouse gases are capable of trapping and reflecting the sun's radiations on the earth's surface. Examples include carbon dioxide, methane, nitrous oxides etc. These are naturally released by activities like volcanic eruptions, forest fires, respiration etc. But their increased levels have occurred due to the anthropogenic activities like deforestation, increased use of refrigerators (releasing CFCs) and increased combustion of coal and petroleum (releasing oxides of nitrogen, sulphur and carbon). Because of the increase in their levels, they have caused climate change by global warming.