The increasing abundance of greenhouse gases in the atmosphere has led to the following effects except

The increasing abundance of greenhouse gases (GHGs) leads to several well-documented environmental impacts. Global warming is the primary effect, as GHGs like CO2, CH4, and N2O trap infrared radiation [2]. Certain GHGs, specifically Chlorofluorocarbons (CFCs), contribute to both the greenhouse effect and the depletion of the stratospheric ozone layer by releasing chlorine atoms that destroy ozone molecules [3]. Furthermore, the 'Carbon dioxide fertilization effect' is a recognized phenomenon where increased atmospheric CO2 concentrations enhance the rate of photosynthesis in plants [t3]. However, there is no scientifically recognized 'Oxygen fertilization effect' associated with GHG abundance. While oxygen is a product of photosynthesis, its atmospheric concentration is not driven by GHG-induced 'fertilization' in the same manner as carbon dioxide, making option 3 the exception.

Sources

1. [2] Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 7: Climate Change > 2. greenhouse gases > p. 11
2. [3] Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 19: Ozone Depletion > tg.r. 7. Environmental Effects of Ozone Depletion > p. 271