The World Bank warned that India could become one of the first places where wet-bulb temperatures ro

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Question

The World Bank warned that India could become one of the first places where wet-bulb temperatures routinely exceed 35°C. Which of the following statements best reflect(s) the implication of the above-said report?Peninsular India will most likely suffer from flooding, tropical cyclones and droughts.The survival of animals including humans will be affected as shedding of their body heat through perspiration becomes difficult.Select the correct answer using the code given below.

Accepted Answer

Correct Answer: B — II onlyStep-by-step Solution:Wet-bulb temperature (WBT) is a measure that accounts for both heat and humidity. It represents the temperature a surface would reach if cooled by evaporation of water. A wet-bulb temperature of 35°C is considered the theoretical upper limit for human survival even with unlimited shade and water, because at this threshold, evaporative cooling (sweating) becomes ineffective — the body cannot shed heat fast enough to prevent a fatal rise in core temperature.Statement I — Peninsular India will suffer flooding, tropical cyclones and droughts: This is not a direct implication of wet-bulb temperatures exceeding 35°C. These events (flooding, cyclones, droughts) are consequences of broader climate change, not specifically of wet-bulb temperature thresholds. Wet-bulb temperature exceedance is specifically about heat stress and human/animal physiological limits — not about precipitation patterns, cyclone frequency, or drought conditions. Statement I conflates different climate change impacts. ✗Statement II — Survival of animals including humans affected as perspiration-based cooling becomes difficult: This is the direct and accurate implication of wet-bulb temperature exceeding 35°C. When ambient wet-bulb temperature reaches 35°C, the human body (which cools itself through sweating/evaporation) cannot dissipate heat effectively because the air is already at the maximum humidity-temperature combination that prevents sweat from evaporating. This leads to hyperthermia (dangerous rise in body temperature), potentially causing death within hours even in healthy individuals. This is precisely what the World Bank report warns about. ✓Why other options are incorrect:Option A (I only): Incorrect. Statement I describes other climate impacts (flooding, cyclones) not directly implied by wet-bulb temperature exceedance.Option C (Both I and II): Incorrect. Statement I is not a direct implication of wet-bulb temperature limits.Option D (Neither): Incorrect. Statement II correctly identifies the implication.Key Concept: Wet-Bulb Temperature (WBT): Measures the cooling effect of evaporation; combines temperature and humidity. WBT is measured by wrapping a thermometer bulb in a wet cloth — the lower the humidity, the more evaporation and the lower the WBT compared to dry-bulb temperature. Critical threshold: WBT of 35°C — beyond this, human body's thermoregulation fails; fatal within 4–6 hours. Current climate projections: With 1.5°C global warming, WBT of 35°C may be reached in humid tropical regions including South Asia and the Gulf. India's concern: Humid coastal and Indo-Gangetic Plain regions are most vulnerable. Heat wave criteria in India (IMD): Plains — temperature ≥45°C or ≥4.5°C above normal; coastal areas lower thresholds. Heat Action Plans: Ahmedabad developed India's first heat action plan (2013) after the 2010 heat wave. NDMA guidelines on heat wave management include WBT-based alert systems.

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