Which one of the following statements is correct regarding Global warming?
- Water vapour does not contribute to global warming.
- Global warming is likely to increase the productivity of plants due to $\mathrm{CO}_{2}$ fertilization.
- CFCs do not cause global warming, but can cause ozone layer depletion in stratosphere.
- HFCs and HCFCs are good substitutes for the ozone depleting substances as they cause neither global warming nor ozone layer depletion.
