This statement is false about greenhouse effect

The correct option is "increased emission of greenhouse gases is a natural process".

Let us analyze each statement to understand why this option is false:
1. "life on earth is possible due to greenhouse effect": This statement is true. Without the natural greenhouse effect, the average temperature of Earth would be around -18°C (0°F) instead of the comfortable 15°C (59°F) we enjoy today. Thus, life as we know it depends on this warming effect.
2. "greenhouse effect is a natural process that maintains earth’s temperature": This statement is true. The greenhouse effect is a naturally occurring phenomenon where certain gases in the atmosphere trap heat radiating from Earth's surface, preventing it from escaping directly into space and thereby maintaining a stable temperature.
3. "increased emission of greenhouse gases is a natural process": This statement is false. While greenhouse gases are emitted through natural sources (like volcanic eruptions and respiration), the modern increased emission of these gases—specifically carbon dioxide, methane, and nitrous oxide—is primarily driven by human activities (anthropogenic activities) such as burning fossil fuels, deforestation, and industrial processes.
4. "increased emission of greenhouse gases in the atmosphere increases earth’s temperature": This statement is true. As human activities increase the concentration of these gases in the atmosphere, more heat is trapped, leading to global warming and an increase in the Earth's average temperature.

Therefore, the statement "increased emission of greenhouse gases is a natural process" is the false statement regarding the greenhouse effect.