La Niña

News: January 2025 recorded the highest global temperatures for any January on record, with the global average surface air temperature rising 1.75°C above pre-industrial levels (1850-1900 average), according to Europe’s Copernicus Climate Change Service (C3S).

About La Niña

• La Niña is a climatic phenomenon and one of the three phases of the El Niño-Southern Oscillation (ENSO) cycle. 
• It is characterized by cooler-than-average sea surface temperatures in the central and eastern tropical Pacific Ocean.
• ENSO operates in three phases, each influencing global weather patterns differently:
  • Neutral Phase – Normal oceanic and atmospheric conditions prevail, with trade winds pushing warm waters towards the western Pacific.
  • El Niño (Warm Phase) – Trade winds weaken, causing warm water to spread across the central and eastern Pacific, leading to increased global temperatures.
  • La Niña (Cool Phase) – Trade winds strengthen, pushing warm waters further west, resulting in cooler oceanic temperatures and generally lower global temperatures.

Impact on Ocean and Atmosphere

• Trade winds strengthen, pushing more warm water towards Asia.
• Increased upwelling occurs off the west coast of the Americas, bringing cold, nutrient-rich water to the surface.
• The jet stream shifts northward, altering weather patterns significantly.

Impact on Weather Patterns

• Northward shift of the jet stream: It leads to drought in the southern U.S.A and heavy rains and flooding in the Pacific Northwest and Canada.
• Winter Temperature Effects: Warmer than normal in the southern U.S.A. and cooler than normal in the northern U.S. and Canada.
• Hurricane Season: La Niña can lead to a more intense and active hurricane season.

Impacts on Marine Life

• Colder Pacific waters during La Niña contain more nutrients.
• This attracts cold-water species like squid and salmon to coastal areas such as California.
• Marine ecosystems flourish due to the increased availability of nutrients.