Greenhouse Gases and Global Warming Mechanisms

Steps:

• Statement 1 claims global warming occurs because more Earth's thermal energy is released to space; this is incorrect as warming results from less energy escaping due to the greenhouse effect.
• Statement 2 states greenhouse gases absorb and emit thermal energy; this is correct, as they trap infrared radiation by absorbing and re-emitting it.
• Statement 3 suggests replacing fossil fuels with hydrogen reduces greenhouse gas levels; this is correct, as hydrogen combustion produces water vapor, not CO2 or other major GHGs.
• Thus, only statements 2 and 3 are accurate, corresponding to option D.

Why D is correct:

• The greenhouse effect definition requires gases to absorb and emit infrared radiation, trapping heat, while hydrogen fuel reduces CO2 emissions per the carbon cycle.

Why the others are wrong:

• A includes incorrect statement 1.
• B selects only false statement 1.
• C includes incorrect statement 1.

Final answer: D