What would happen to the state of Earth's oceans if the greenhouse effect ceased to exist?

• A. They would freeze over due to lower temperatures.
• B. They would boil away due to higher energy
• C. They would become highly acidic
• D. They would have no change in state

Answer: (A)

The main idea is that the greenhouse effect keeps a significant amount of heat near Earth’s surface by trapping infrared radiation in the lower atmosphere. If the greenhouse effect vanished, the atmosphere would no longer trap that heat, so more energy escapes to space and the global average temperature would fall.

With global temperatures dropping, the ocean—the planet’s largest heat reservoir—would cool, and surface waters would reach freezing temperatures in many areas. Over time, widespread sea-ice formation would occur, effectively making large parts of the oceans ice-covered. The other options don’t fit because removing heat-trapping would not cause boiling (that requires more heat, not less), wouldn’t inherently make oceans more acidic, and would certainly lead to a change in the state of the oceans as they cool and freeze.