Climate Change and Health
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Direct answer
Climate change is, in the World Health Organization's phrase, the single biggest health threat facing humanity — and its clinical face in India is the heatwave, the flood, the shifting malaria map and the failed monsoon harvest. Direct effects are heat cramps, heat exhaustion and heatstroke (a core temperature above 40 degrees with central nervous system dysfunction — a medical emergency cooled aggressively), plus injuries and drowning in extreme weather; indirect effects dominate the burden through expanded vector ranges, water-borne outbreaks after floods, crop failure and undernutrition, and mental health consequences of displacement. The policy architecture a candidate must cite: the Paris Agreement 2015 (holding warming well below 2 degrees, pursuing 1.5), India's National Action Plan on Climate Change 2008 with its eight missions, the National Programme on Climate Change and Human Health initiated in 2019, and Ahmedabad's 2013 heat action plan — South Asia's first.
What you must remember
- Heat illness spectrum: heat cramps → heat exhaustion (salt and water depletion, sweating preserved, core under 40) → heatstroke (anhydrosis or sweating, core above 40, altered sensorium; rapid cooling with water and fanning, zero mortality only if cooled within the first hour).
- IMD heatwave criteria (plains): maximum temperature at least 40 degrees with departure from normal of 4.5-6.4 degrees; departure above 6.5 degrees is a severe heatwave.
- National Action Plan on Climate Change (2008): eight missions — solar, enhanced energy efficiency, sustainable habitat, water, Himalayan ecosystem, Green India, sustainable agriculture and strategic knowledge.
- NPCCHH (2019): the health ministry's programme — heat illness surveillance, state and city climate-health adaptation plans, greening of health facilities, capacity building.
- Heat action plans: Ahmedabad 2013 was South Asia's first, after the 2010 heatstorm; early warning, cool roofs, oral rehydration corners and vulnerable-person tracking are its template.
- Vector-borne shifts: Aedes and Anopheles ranges moving to higher altitudes and new seasons; malaria modelling projects shifts in endemic districts.
- Mitigation co-benefits: clean energy cuts both carbon and PM2.5; active transport cuts emissions, obesity and diabetes together — the argument examiners like called "health co-benefits".
- Global milestones: Paris 2015; India's net-zero commitment by 2070 announced at COP26 Glasgow (2021); WHO calls the climate response "the greatest opportunity for global health".
One heatwave worked end to end
An May afternoon in Nagpur touches 47 degrees. The city heat action plan activates: the meteorological alert reached the health department two days earlier, hospitals pre-positioned cooling rooms and ORS, and anganwadi workers checked on elderly list-makers. Casualty still receives a 60-year-old farmer, obtunded, core temperature 41.5, skin dry — classic heatstroke; he is sprayed and fanned while ice packs grip the groin and axillae, because the target is a core temperature below 39 degrees within the first hour. Simultaneously the surveillance officer counts heat stroke and heat exhaustion cases into the NPCCHH reporting format, which by next season justifies a bigger cool-roof programme. The same week a cloudburst floods a settlement downstream: leptospirosis prophylaxis, chlorination and diarrhoea preparedness follow. One climate event, therefore, exercises the entire preventive toolkit — early warning (primordial), preparedness (primary), early treatment (secondary) and rehabilitation (tertiary).
The angle examiners probe
The favourite stem contrasts heat exhaustion with heatstroke on sweating and sensorium — heat exhaustion keeps both, heatstroke loses the brain and may keep or lose sweating; the treatment answer is always rapid external cooling, not antipyretics (paracetamol does nothing in heatstroke). The second probe is naming the programme — many candidates still write only NAPCC 2008 and miss the health-specific NPCCHH 2019, which is precisely the discriminating option. Third, know the numbers: eight NAPCC missions, net-zero 2070, 1.5 degrees as the aspirational Paris limit. Finally, framing matters: climate acts on health mostly indirectly — through vectors, water, food and displacement — so a "direct effect" question's answer is heat illness and weather injuries, not malaria.
Frequently asked questions
Which programme addresses climate change impacts on health in India?
The National Programme on Climate Change and Human Health, initiated in 2019, covering heat illness surveillance, adaptation plans and climate-resilient health facilities.
How does heatstroke differ from heat exhaustion?
Heat exhaustion preserves consciousness and sweating with a core temperature below 40 degrees; heatstroke presents with core above 40 and central nervous system dysfunction and is cooled as an emergency.
What was India's first heat action plan and when?
Ahmedabad's 2013 plan, developed after the severe 2010 heatwave — the first in South Asia, combining early warnings with hospital preparedness.
What are the mitigation co-benefits of climate action for health?
Cleaner energy lowers particulate pollution and carbon together, and walking-cycling transport cuts emissions while reducing obesity, diabetes and cardiovascular disease.
Which climatic factors expand vector-borne disease?
Rising temperatures, altered rainfall and humidity extend vector breeding seasons and push Aedes and Anopheles into higher altitudes and new geographies.