The correct option is 2 only
Explanation
The effectiveness of a greenhouse gas (GHG) in contributing to global warming is determined by its Global Warming Potential (GWP) and Radiative Forcing. These metrics depend on the gas's physical properties, its abundance, and its behavior in the atmosphere.
Statement 1 is Incorrect: The magnitude of the increase in concentration is a primary factor in determining the total warming effect of a gas. Radiative forcing is calculated based on the difference in concentration relative to pre-industrial levels. A higher concentration generally results in greater absorption of outgoing terrestrial radiation.
Statement 2 is Correct: The atmospheric lifetime of a gas has a significant bearing on its effectiveness. Gases that persist in the atmosphere for long periods (e.g., Carbon Dioxide, Nitrous Oxide) accumulate and exert a warming influence over centuries. Global Warming Potential (GWP) is explicitly calculated over specific time horizons (e.g., 20 or 100 years) to account for this lifetime.
Statement 3 is Incorrect: The wavelength of radiation a molecule absorbs is highly relevant. Greenhouse gases function by absorbing specific wavelengths of outgoing long-wave (infrared) radiation. Molecules that absorb radiation in the "atmospheric window" (wavelengths not significantly absorbed by water vapor or CO2) are disproportionately effective at trapping heat.
Key Takeaway: The potency of a greenhouse gas depends on three critical factors: its radiative efficiency (ability to absorb specific wavelengths), its atmospheric lifetime, and its abundance (concentration) in the atmosphere.