Environmental statements and climate impacts: Identify the correct statement regarding greenhouse effect, global warming, atmospheric chemistry, and air toxics.

Introduction / Context:
Climate and air quality literacy requires distinguishing accurate statements from common misconceptions. Greenhouse forcing mechanisms, natural atmospheric chemistry, and health effects of pollutants are frequently mischaracterized. This item asks you to select the correct statement among four concise claims about deforestation, global warming, lightning chemistry, and sulphur dioxide health effects.

Given Data / Assumptions:

• Greenhouse effect refers to warming due to heat-trapping gases (e.g., CO2, CH4, N2O).
• Extreme weather and agricultural productivity are sensitive to climate change.
• Lightning-driven chemistry predominantly involves nitrogen species.
• SO2 is a respiratory irritant rather than a simple asphyxiant.

Concept / Approach:
Evaluate each claim against well-established environmental science. Deforestation removes a carbon sink and typically worsens greenhouse gas accumulation. Global warming can reduce yields through heat stress, droughts, floods, and pest pressure, and it is associated with changing patterns and intensities of extreme events. Lightning discharges primarily produce nitrogen oxides (NO and NO2), not sulphur gases. Sulphur dioxide causes bronchoconstriction and airway irritation; its lethality is not via classic asphyxiation like carbon monoxide or nitrogen displacement.

Step-by-Step Solution:
Check option A: false; deforestation intensifies greenhouse forcing.Check option B: true; warming can diminish crop productivity and increase flood/cyclone risks through altered hydrology and storm dynamics.Check option C: false; lightning is a major natural source of NOx, not SO2 or H2S.Check option D: false; SO2 irritates and inflames airways; death is usually from respiratory failure, not asphyxia via haemoglobin binding.

Verification / Alternative check:
IPCC assessments and agronomic studies report yield declines for staples beyond certain temperature thresholds and increased risk of hydrometeorological extremes, corroborating option B.

Why Other Options Are Wrong:
A: Deforestation reduces carbon sequestration; it does not control greenhouse effect.C: Misstates lightning chemistry.D: Misclassifies toxicological mechanism of SO2.

Common Pitfalls:

• Conflating any harmful gas with an asphyxiant.
• Assuming all natural electrical activity yields sulphur pollutants.

Final Answer:
Global warming is detrimental for food productivity and may lead to floods and cyclones.