Question

Which of the following is true concerning the balance between the solar energy absorbed and radiated by Earth?
a.
Earth’s atmosphere absorbs a larger fraction of total solar energy than it radiates.
b.
More than 90% of the solar energy that strikes Earth is absorbed.
c.
Earth’s surface is responsible for absorbing a larger fraction of energy than it radiates.
d.
None of the above.

Answer 1

Answer: d. None of the above.

Why:
- About 30% of incoming solar radiation is reflected back to space; roughly 70% (~239 W/m²) is absorbed by the Earth system.
- The atmosphere directly absorbs only ~20–25% of incoming solar, but it radiates much more energy as thermal infrared (so (a) is false).
- Less than 100% (about 70%) of solar energy is absorbed overall, not more than 90% (so (b) is false).
- The surface absorbs a substantial fraction of the solar energy (~45–50% of incoming), but it emits (radiates) more energy as longwave thermal radiation than it directly absorbs from the Sun (so (c) is false).

Thus none of the three given statements is correct.