“Understanding El Niño and La Niña: How These Climate Phenomena Impact Global Weather Patterns”

The India Meteorological Department (IMD) recently forecasted above-normal rain in the upcoming monsoon season in India, with favorable La Nina conditions expected to set in by August-September. This news has sparked interest and curiosity among many, as the onset and withdrawal of conditions related to El Nino or La Nina can have significant impacts on different parts of the world.

El Nino and La Nina are climate phenomena that result from ocean-atmosphere interactions, affecting the temperature of waters in the central and eastern tropical Pacific Ocean. These phenomena have a global impact on weather patterns. Under normal ocean conditions, trade winds blow westwards along the equator, resulting in upwelling where cold water rises and displaces warm surface waters. However, during El Nino, weak trade winds get pushed back towards South America, leading to warmer sea surface temperatures along the equatorial Pacific Ocean. On the other hand, during La Nina, strong trade winds push warm water towards Asia, resulting in colder and nutrient-rich water towards South America.

The ongoing El Nino event, which began in June last year, has weakened significantly, and neutral ENSO conditions are likely to be established by June. La Nina conditions are expected to emerge thereafter, with impacts expected from August onwards. The IMD has forecasted above-normal rainfall for the upcoming monsoon season in India, with the seasonal rainfall expected to be 106 percent of the Long Period Average (LPA).

During La Nina years, east and northeast India typically receive below-average seasonal rainfall, leading to potential water shortages in those regions. Thunderstorms and lightning activity also tend to increase during La Nina years, posing risks to farming activities and human safety. Other regions around the world, such as Indonesia, the Philippines, Malaysia, and southern Africa, may experience varying impacts from La Nina, including floods, droughts, and changes in hurricane activity over the Atlantic Ocean.

Climate change is also expected to impact the ENSO cycle, with studies suggesting that global warming may trigger more El Nino events in the future. The World Meteorological Organization (WMO) has warned that climate change could affect the intensity and frequency of extreme weather events linked to El Nino and La Nina.

Overall, the onset of La Nina conditions and the potential impacts on global weather patterns are significant factors to monitor and understand, as they can have far-reaching consequences on agriculture, water resources, and natural disasters in various regions around the world.