The increasing abundance of greenhouse gases in the atmosphere has led to various effects, but the option that does not fit in this list is option 3: Oxygen fertilization effect.

1. Global warming: The increase in greenhouse gases like carbon dioxide, methane, and nitrous oxide results in more heat being trapped in the Earth`s atmosphere, leading to global warming. This causes the Earth`s average temperature to rise, leading to various climate changes and extreme weather events.

2. Depletion of ozone layer in the stratosphere: Certain human-made chemicals like chlorofluorocarbons (CFCs) can deplete the ozone layer in the stratosphere. The ozone layer protects us from harmful ultraviolet (UV) radiation, and its depletion increases the risk of skin cancer, cataracts, and other health issues.

4. Carbon dioxide fertilization effect: Increased levels of carbon dioxide can enhance plant growth through a process known as carbon dioxide fertilization effect. Plants use carbon dioxide in the process of photosynthesis to produce food, so an abundance of carbon dioxide can potentially increase crop yields.

It is important to note that option 3, the oxygen fertilization effect, is not directly related to greenhouse gases. Oxygen fertilization effect refers to the increase in oxygen