How Global Warming is affecting India’s Monsoon Patterns

How Global Warming is affecting India’s Monsoon Patterns explores shifting rainfall trends, extreme weather events, and the impact on agriculture, water resources, and livelihoods.

Table of Contents

Context: Global warming is making India’s southwest monsoon increasingly unpredictable by weakening traditional circulation patterns and fueling extreme weather with excess atmospheric moisture.

India’s Southwest Monsoon

It refers to the seasonal reversal of winds bringing moist air from the Indian Ocean to the Indian subcontinent, causing ~75% of India’s annual rainfall.

Causes:
- Differential heating: Land heats faster than the ocean → creating low pressure over the Indian subcontinent, drawing in moist oceanic air.
- ITCZ shift: The Inter-Tropical Convergence Zone (ITCZ) moves northwards over India during summer, aiding monsoon onset.
- Tropical Easterly Jet: Helps in transporting moisture into the subcontinent.
- Orography: Western Ghats, the Himalayas block moist winds, leading to heavy rainfall on windward sides.
Significance:
- Agriculture: Supports ~50% of India’s net sown area and ~40% of food production.
- Water Resources: Recharges groundwater, rivers, and reservoirs.
- Economy: Impacts food security, inflation, energy (hydropower), and rural livelihoods

Causes/Drivers of Monsoon Changes

Weakened monsoon circulation: Rising sea levels and rising temperatures have disrupted the pressure gradients that traditionally drive monsoon winds.
Warming and moisture paradox: Increased atmospheric temperatures allow air to hold ~7% more moisture per °C, leading to heavy rain bursts separated by longer dry spells.
Ocean–atmosphere dynamics: Enhanced ocean warming promotes upward moist air movement over the equatorial ocean, triggering dry descending air (subsidence) over land and inhibiting rainfall.
Tropical Easterly Jet weakening: The weakening of this jet has contributed to reduced rainfall in central and certain parts of northern India.
Regional warming effects: Warming in the Middle East and Arabian Sea has intensified pressure gradients, drawing more moisture toward west and northwest India.
Climate change–driven variability: Climate models predict a surge in extreme rainfall and delayed/unpredictable monsoon onset and progression.

Anthropogenic Causes

Greenhouse Gas Emissions (Global Warming): Rising CO₂ and other GHGs → increase surface air temperature → Warmer air holds more moisture, causing intense downpours and longer dry spells.
Aerosols & pollution → reduce sunlight (dimming), alter cloud formation.
Deforestation & land use change → less evapotranspiration, disturbed local rain cycles.
Climate Change–Induced Ocean Alterations: Anthropogenic warming has raised Indian Ocean temperatures, shifting circulation patterns (Indian Ocean Dipole) → Weakens Tropical Easterly Jet and monsoon circulation.

Impacts

Geographic shift in monsoon rains:
- Rain moving away from heartland: Decrease in rainfall over eastern, central, and northern India (traditional agricultural core). Increase in western regions like Gujarat and scattered northeast areas.
- Extreme downpours spread: Increase in western India and the Himalayan regions (Himachal Pradesh, Uttarakhand); decrease in parts of eastern and southern India.
Intensifying humid heat: Alternating dry and wet spells with high moisture during dry phases increase heat stress on populations.
Monsoon-linked public health risks: Conditions of >27 °C temperature, moderate rain, and 60‑78% humidity elevate dengue risk.
Record monsoon extremes (2025): North India experienced its wettest monsoon in 12 years-21% above normal-with record “extremely heavy” rainfall events.
Glacial and Himalayan risks: Accelerated glacier melt raises flood and landslide risk; monsoon flooding already caused mass casualties.
Urban flooding & infrastructure stress: Mumbai’s August 2025 rains nearly doubled average monthly totals.

Challenges Ahead

Forecasting weakening: The weakening traditional links, such as El Niño–monsoon coupling, hinder seasonal prediction.
Cloudburst monitoring gaps: Extremely sudden, localised cloudbursts (>100 mm/hour) are increasingly deadly but poorly monitored.
Infrastructure & civic preparedness: Cities struggle to handle flash floods-Hyderabad’s drainage was overwhelmed, despite 155 weather stations and response planning.
Health & migration: Climate‑linked health burdens (like dengue) and displacement risks rise amid changing monsoon regimes.

Way Forward / Strategic Measures

Better monitoring & forecasting: Closing gaps in cloudburst detection and seasonal forecasting systems.
- Scientific innovations: AI + satellite data for nowcasting; Doppler radars expansion.
Public health adaptation: Plan for dengue risk based on temperature and humidity trends.
Early warning systems & localised planning: Urgent need for granular, tehsil‑level monsoon action plans based on regional variability.
Urban resilience: Implement climate‑resilient infrastructure: lakes/ponds, clear drains, green spaces; seen as critical after Delhi floods.
Resilient agriculture: Drought-resistant & flood-tolerant varieties (e.g., Submergence-tolerant rice “Swarna-Sub1”).
Mitigation-greenhouse gas reductions: Long‑term adaptation must be coupled with aggressive GHG reduction-emissions control remains vital.
Policy initiatives: Strengthen climate‑resilient agriculture, urban planning, and disaster management under NAPCC and Panchamrit commitments.
Community awareness & public health outreach: Educate vulnerable communities about heat, health risks (like dengue), and emergency protocols.