Article 2: Climate Systems and Extreme Weather Events in India
Why in News: India is witnessing a summer marked by unseasonal rainfall, rising heatwaves, and increasing humidity due to the combined influence of Western Disturbances, El Niño conditions, and climate change-driven weather variability.
Key Details
- Western Disturbances recently brought unseasonal rainfall, hailstorms, and temperature fluctuations across North India. These systems have affected agriculture, urban infrastructure, and local weather stability during the pre-monsoon season.
- El Niño conditions are likely to weaken the southwest monsoon and intensify heatwaves during summer 2026. Historically, many drought years in India have coincided with strong El Niño events in the Pacific Ocean.
- Increasing humidity levels are making temperatures feel significantly hotter than the actual recorded temperature. This has increased concerns regarding heat stress, public health risks, and declining labour productivity.
- Climate scientists have observed a rise in extreme weather events including floods, heatwaves, and erratic rainfall. This trend is increasingly linked with global warming and disruptions in atmospheric circulation patterns.
Western Disturbances
- Definition: Western Disturbances are eastward-moving extra-tropical cyclones originating near the Mediterranean region. They travel towards India through Iran, Afghanistan, and Pakistan before affecting northwestern India.
- Associated Weather: These systems bring winter rainfall and snowfall to North India and the Himalayan region. During summer months, they can also trigger unseasonal rain, thunderstorms, and hailstorms.
- Jet Stream Connection: Western Disturbances are embedded in the Subtropical Westerly Jet Stream. This high-altitude air current plays a major role in influencing winter and pre-monsoon weather patterns in India.
- Agricultural Importance: Winter rainfall caused by these systems is beneficial for Rabi crops such as wheat and mustard. However, excessive untimely rainfall can damage standing crops and affect food security.
El Niño Southern Oscillation
- Definition: ENSO is a climate phenomenon involving periodic warming and cooling of sea surface temperatures in the Pacific Ocean. It significantly affects global weather systems, including rainfall and temperature patterns in India.
- Three Phases: ENSO has three phases — El Niño, La Niña, and Neutral conditions. These phases generally occur every two to seven years and influence monsoon circulation differently.
- El Niño Impact on India: During El Niño, eastern Pacific waters become warmer than usual. This weakens moisture-bearing winds towards India, often leading to below-normal monsoon rainfall.
- La Niña Conditions: During La Niña, eastern Pacific waters become cooler than normal. This generally strengthens the Indian monsoon and may sometimes increase flood risks.
Heat Waves in India
- Definition: A heat wave is a prolonged period of abnormally high temperatures over a region. The India Meteorological Department declares heat waves based on temperature thresholds and deviation from normal conditions.
- IMD Criteria: Heat wave conditions are declared when temperatures exceed 40°C in plains and remain significantly above normal. In coastal areas, humidity is also considered due to its impact on human discomfort.
- Rising Frequency: India has witnessed increasing frequency and intensity of heatwaves in recent decades. Climate change and rapid urbanisation have amplified this trend significantly.
- Socio-Economic Impact: Heatwaves affect public health, agriculture, water availability, and labour productivity. Vulnerable groups such as elderly people, outdoor workers, and urban poor face the greatest risks.
Wet Bulb Temperature
- Definition: Wet Bulb Temperature measures the lowest temperature achievable through evaporative cooling. It reflects the combined effect of temperature and humidity on the human body.
- Human Survival Threshold: Sustained wet bulb temperatures above 35°C can become life-threatening. At such conditions, the human body loses its ability to cool itself effectively through sweating.
- Climate Change Link: Rising global temperatures and humidity levels are increasing wet bulb temperatures worldwide. This raises serious concerns for tropical countries like India during extreme summer months.
- Public Health Concern: High wet bulb temperatures increase risks of dehydration, heatstroke, and cardiovascular stress. They particularly affect densely populated urban regions with poor ventilation and high humidity.
“Feels Like” Temperature and Humidity Effects
- Definition: “Feels Like” or apparent temperature represents how hot conditions feel after accounting for humidity and wind. It is different from the actual air temperature measured by thermometers.
- Role of Humidity: High humidity reduces evaporation of sweat from the human body. This makes conditions feel much hotter and increases physiological stress.
- Regional Variation: A dry 40°C temperature in Delhi feels different from humid 40°C conditions in Kerala. Humid climates often cause greater discomfort despite similar actual temperatures.
- Urban Heat Stress: High apparent temperatures are becoming common in Indian cities due to concrete infrastructure and pollution. This increases health risks and energy demand during summer.
Climate Change and Extreme Weather Events
- Scientific Evidence: The Intergovernmental Panel on Climate Change has linked climate change with rising frequency of extreme weather events. These include heatwaves, heavy rainfall, droughts, and cyclones.
- Changing Rainfall Patterns: India is witnessing shorter but more intense rainfall spells. This increases flood risks while simultaneously causing long dry periods.
- Urban Vulnerability: Rapid urbanisation and poor planning intensify the impact of extreme weather events. Encroachment on wetlands and inadequate drainage worsen urban flooding.
- Global Trend: Similar climate extremes are being observed across different continents. This highlights the transboundary and global nature of climate change impacts.
India’s Climate Response and Preparedness
- Heat Action Plans: Several Indian cities have introduced Heat Action Plans to reduce heatwave mortality. Ahmedabad’s model is often cited as a successful example of local adaptation.
- Early Warning Systems: IMD has improved weather forecasting and alert dissemination mechanisms. These systems help governments prepare for extreme weather events in advance.
- National Action Plan on Climate Change (NAPCC): India launched missions focusing on solar energy, water conservation, and sustainable habitat. The plan aims to strengthen climate resilience and low-carbon development.
- Disaster Preparedness: Agencies such as NDMA coordinate responses to climate-induced disasters. However, implementation gaps and urban governance challenges remain significant concerns.
Important Examples
- 2015 Chennai Floods: Caused by extreme rainfall combined with poor urban drainage systems. It exposed weaknesses in urban planning and disaster management.
- 2022 Heatwave in India: March and April 2022 were among the hottest months recorded in India. The heatwave affected wheat production and electricity demand significantly.
- 2018 Kerala Floods: Triggered by exceptionally high rainfall and reservoir management challenges. It became one of the worst natural disasters in Kerala’s history.
- Urban Flooding in Bengaluru and Mumbai: Frequent flooding reflects the impact of unplanned urbanisation. Encroachment of lakes and drainage channels has worsened the problem.
Way Forward
- Climate-Resilient Infrastructure: Indian cities need improved drainage systems, green spaces, and heat-resilient infrastructure. This will reduce vulnerability to floods and urban heat stress.
- Improved Climate Forecasting: Investment in weather models and observational networks is essential. Better forecasts can strengthen early warning systems and preparedness.
- Sustainable Urban Planning: Wetlands, lakes, and natural drainage systems must be protected. Integrated urban planning is critical for long-term resilience.
- Public Awareness and Adaptation: Citizens must be educated about heat safety, water conservation, and disaster preparedness. Community participation can significantly improve resilience against climate extremes.
Conclusion
India’s climate challenges are no longer limited to monsoon variability alone. Rising heatwaves, humidity stress, erratic rainfall, and extreme weather events highlight the growing impact of climate change. Strengthening climate resilience through scientific forecasting, sustainable planning, and adaptive governance will be essential for protecting lives, livelihoods, and long-term development.
EXPECTED QUESTION FOR UPSC CSE
Prelims MCQ
Q. With reference to climate systems affecting India, consider the following statements:
- Western Disturbances originate in the Mediterranean region and influence winter rainfall in North India.
- El Niño conditions generally strengthen the Indian southwest monsoon.
- Wet bulb temperature reflects the combined effect of heat and humidity on the human body.
How many of the above statements are correct?
(a) Only one
(b) Only two
(c) All three
(d) None
Answer: (b)
MAINS PRACTICE QUESTION
Q. “Climate change is increasing the frequency and intensity of extreme weather events in India.” Discuss with reference to heatwaves, extreme rainfall, and monsoon variability. (250 words, 15 marks)