Answer: The green house gases plays an important role in controlling the overall temperature of the earth. A small increase in the composition (in terms of ppm/ppb) of these green house gases in the atmosphere, such as CO2, water vapour, methane, CFC etc can lead to a subsequent increase in the earth's average temperature, which could be sufficient enough for the melting of the ice at Antarctica.
Thus , it will also be affecting the biosphere as the sea level will rise, surface temperature will increase and life would be difficult to sustain.
- Note- ppm stands for parts per million
ppb stands for parts per billion