19 Dec La Niña: The Blessing in Disguise for India’s Weather Patterns
SYLLABUS MAPPING:
GS-1-Geography-La Niña: The Blessing in Disguise for India’s Weather Patterns
FOR PRELIMS:
What is La Niña its formation mechanism, and its impacts on global climate and conditions related to La Niña?
FOR MAINS:
Why in the news?
What is La Niña?
La Niña is the cold phase of the El Niño/Southern Oscillation (ENSO) cycle, which represents a periodic fluctuation in sea surface temperatures and atmospheric pressures in the equatorial Pacific Ocean. During La Niña, cooler-than-average sea surface temperatures occur in the central and eastern Pacific, leading to significant shifts in global weather patterns.
Features of La Niña:
1. Cooler Sea Surface Temperatures: La Niña is characterized by below-average sea surface temperatures in the central and eastern Pacific Ocean.
2. Atmospheric Changes: The cooling of the ocean leads to stronger-than-normal trade winds that push warm water toward the western Pacific, leading to higher-than-usual sea surface temperatures in the western Pacific and around Indonesia.
3. Global Weather Impacts: Warmer and drier conditions in parts of the southern United States, the southern tier of the U.S., and parts of the Gulf Coast. Increased rainfall in countries like Indonesia, the Philippines, and northern Australia. Colder winters in the northern U.S. and Canada. Drier conditions in parts of South America, especially the western coast, like Peru and Ecuador.
4. Tropical Cyclone Disruption: La Niña increases hurricane activity in the Atlantic while reducing storms in the Pacific.
5. Agricultural Impact: La Niña causes droughts in South America (e.g., Argentina, Brazil) and floods in Southeast Asia, disrupting crop yields.
Impacts of La Niña on global climate:
1. Stronger Trade Winds: During La Niña, trade winds strengthen, pushing more warm water toward Asia. Results in cooler-than-average sea surface temperatures in the central and eastern Pacific.
2. Upwelling and Ocean Conditions: The cooler waters caused by La Niña increase upwelling off the west coast of the Americas. Nutrient-rich, cold water rises, impacting marine ecosystems and fisheries.
3. Jet Stream Shift: Cold Pacific waters push the jet stream northward. Alters weather patterns, with drier conditions in the southern U.S. and wetter conditions in the Pacific Northwest and Canada.
4. Regional Temperature Variations: Shifts in the jet stream and atmospheric patterns. Warmer-than-normal winter temperatures in the southern U.S. and cooler-than-normal temperatures in the northern U.S. and Canada.
5. Droughts and Flooding: La Niña causes abnormal rainfall patterns.
Drought in the southern U.S., with heavy rains and flooding in the Pacific Northwest and parts of Canada.
Impacts of La Niña on Indian climate:
| Impact | Description |
|---|---|
| Rainfall | La Niña often brings above-normal rainfall during the southwest monsoon, benefiting agriculture by providing water for crops, but excessive rainfall can cause flooding. |
| Temperature | Colder-than-usual winters in northern India, with slightly warmer daytime temperatures, which may affect energy consumption and agricultural cycles. |
| Summer | Reduced intensity of summer heat, providing relief from heatwaves, especially in northern and central India, mitigating heat stress on people and crops. |
| Air Quality | Higher wind speeds help disperse air pollution, improving air quality, particularly in urban areas like Delhi, which face chronic pollution issues. |
| Agriculture | Increased rainfall can support crop growth, but excessive rainfall in flood-prone areas may damage crops, reducing yields and causing losses for farmers. |
| Fisheries | Cooling of ocean waters supports marine life, improving fishing conditions off India’s coasts, but may also affect fish species diversity. |
| Wildfires | Reduced heat and increased rainfall lower the risk of wildfires in regions like the Western Ghats, though flooding could still cause landslides and erosion. |
| Economy | Above-normal rainfall and flooding can impact crop production, food supply, and exports. The fishing sector may benefit from improved conditions, supporting the coastal economy. |
| Flooding | Excessive rainfall can lead to flooding in low-lying areas and river basins, disrupting transportation, displacing people, and causing economic damage. |
Significance of La Niña:
1. Enhanced Rainfall: Above-normal monsoon rains boost agriculture, especially in water-scarce regions, leading to higher crop yields.
2. Reduced Summer Heat: La Niña helps lower the intensity of heatwaves, offering relief to both people and crops.
3. Improved Air Quality: Stronger winds disperse air pollution, improving air quality, particularly in urban areas like Delhi.
4. Boost to Fisheries: Cooler ocean waters support marine life, benefiting coastal fisheries with better fishing conditions.
5. Lower Wildfire Risk: Increased rainfall and cooler temperatures reduce the chances of wildfires in vulnerable regions.
6. Drought Mitigation: Extra rainfall helps mitigate drought conditions, supporting agriculture and water supplies.
Conclusion:
La Niña, forecasted to occur in late 2024 or early 2025, brings both challenges and benefits to India. It can enhance monsoon rainfall, support agriculture in water-scarce regions, and reduce summer heat, offering relief from heat waves. Cooler ocean temperatures benefit fisheries, while stronger winds improve air quality in urban areas like Delhi. Additionally, lower wildfire risk and drought mitigation are key advantages. However, the potential for flooding requires careful management to minimize disruptions. Overall, La Niña presents opportunities for agriculture, energy, and the environment but also demands proactive planning.
Download Plutus IAS Current Affairs (ENG) 19th Dec 2024
Prelims Question:
Q. Which of the following statements regarding La Niña are correct?
1. La Niña is characterized by cooler-than-average sea surface temperatures in the central and eastern Pacific Oceans.
2. La Niña tends to cause drought in Southeast Asia and flooding in South America.
3. During La Niña, the jet stream shifts northward, bringing drier conditions to the southern United States and wetter conditions to the Pacific Northwest.
4. La Niña has no significant impact on India’s monsoon season.
Select the correct answer using the code below:
A. 1, 3 only
B. 1, 2, 3 only
C. 2, 4 only
D. 1, 3, 4 only
Answer: A
Mains Question:
Q. Briefly explain the significant effects of La Niña on global and regional weather patterns. Discuss the impacts of La Niña on India’s climate, agriculture, and economy.
(250 words, 15 marks)
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