EL Nino Effect
Context: In a new study, researchers have found that because of climate change, extreme El Niño events are likely to become more frequent.
Key findings:
- There is a shift in El Niño behaviour since the late 1970s.
- All events beginning in the eastern Pacific occurred prior to that time, while all events originating in the western-central Pacific happened since then.
- Therefore, climate change effects have shifted the El Niño onset location from the eastern Pacific to the western Pacific, and caused more frequent extreme El Niño events.
What is El Nino?
- El Nino is a climatic cycle characterised by high air pressure in the Western Pacific and low air pressure in the eastern.
- During this event, there is a warming of the sea surface temperature in the eastern and central equatorial Pacific Ocean.
- It is one phase of an alternating cycle known as El Niño Southern Oscillation (ENSO).
What causes El Nino?
El Nino sets in when there is anomaly in the pattern.
- The westward-blowing trade winds weaken along the Equator and due to changes in air pressure, the surface water moves eastwards to the coast of northern South America.
- The central and eastern Pacific regions warm up for over six months and result in an El Nino condition.
Impact:
- The temperature of the water could rise up to 10 degrees Fahrenheit above normal.
- Warmer surface waters increase precipitation and bring above-normal rainfall in South America, and droughts to Indonesia and Australia.
- Favours eastern Pacific hurricanes and tropical storms. Record and unusual rainfall in Peru, Chile and Ecuador are linked to the climate pattern.
- Reduces upwelling of cold water, decreasing the uplift of nutrients from the bottom of the ocean. This affects marine life and sea birds. The fishing industry is also affected.
- A recent WHO report on the health consequences of El Nino forecasts a rise in vector-borne diseases, including those spread by mosquitoes, in Central and South America. Cycles of malaria in India are also linked to El Nino.
