Without natural global warming, what would the average temperature on Earth likely be?

• A. -10°C
• B. -18°C
• C. 0°C
• D. 5°C

Answer: (B)

The average temperature on Earth without natural global warming would likely be around -18°C. This temperature reflects the state of the planet without the greenhouse effect, which is essential for maintaining a livable climate.

Natural global warming is primarily influenced by greenhouse gases in the atmosphere, such as carbon dioxide and methane, which trap heat from the sun and keep the planet warm enough to sustain life. Without these gases, the Earth's surface would radiate heat back into space more effectively, leading to significantly lower average temperatures.

At -18°C, many parts of the Earth would be inhospitable, with water freezing in most locations, making it extremely challenging for most forms of life to survive. This stark contrast illustrates the crucial role that natural atmospheric conditions play in making Earth a habitable environment.