El-Nino
Why in news:
- On June 20 Australia’s Bureau of Meteorology said sea surface temperatures (SSTs) across the equatorial Pacific Ocean have warmed to El Nino threshold and are likely to rise by 3.2 degrees Celsius by November, well above the Indian Met’s forecast.
- The formation of Elnino is likely to affect the production of key crops and could even alter the trade routes for their markets.
What is El Nino ?
- El Nino is the warming of sea water in the central-east Equatorial Pacific that occurs every few years.
- Normally, easterly trade winds blow from the Americas towards Asia.
- Due to El Nino, they falter and change direction to turn into westerlies, bringing warm water from the western pacific towards the Americas.
- During El Nino, surface temperatures in the equatorial pacific rise, and trade winds that blow near the Equator weaken.
- El Nino impacts on marine life :
- The phenomena of upwelling (nutrient-rich waters rise towards the surface) is reduced under El Nino.
- Due to reduced upwelling, phytoplankton are reduced. This will automatically reduce the fishes that are dependent on the phytoplankton.
- Warm water from tropical areas carry tropical species towards colder areas, disrupting multiple ecosystems.
- Impact on climate :
- El Nino causes dry warm winter in Northern U.S. and Canada.
- It increases the risk of flooding in the U.S. gulf coast and southeastern U.S.
- It also brings drought to Indonesia and Australia.
- Impact on India :
- El Nino causes weak rainfall and more heat.
- It may cause severe drought conditions in some parts of India.
Syllabus: Prelims
