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Name: Tony
Status: student
Age: 12
Location: N/A
Country: N/A
Date: 2000-2001

I would like to know the difference between El Nino and La Nina, what would the world weather patterns be like if El Nino and La Nina were not present. Also, what is Upwelling? Does it have something to do with warm water combining with cold water? Thank you.


El Nino is the condition when the atmosphere and ocean currents cause a movement of warmer water to the eastern Pacific. There is kind of a snowball effect when the process begins that can result in severe warming of the ocean off the northern west coast of South America. This prevents water from deeper in the ocean from upwelling to the surface. Nutrients and food for fish do not get to the upper layer of ocean for food fish to eat. This causes fish to migrate further south, disrupting the South American fishing industry and causing severe drought in western South America. This also, usually, causes drought in the southwestern part and plains of North America.

La Nina is the opposite condition, when warm water builds up in the western Pacific Ocean, often causing drought conditions there and leaving northern South America with floods and northern North America with mild, wet summers and drought in the southeastern United States.

In between El Nino and La Nina are "normal" conditions. So, if the El Nino and LA Nina did not occur, we would have less variable weather conditions. This would be better for agriculture and the fishing industry, at least.

David Cook
Argonne National Laboratory

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