Get ready: El Niño is coming! It makes earth hotter and changes global climate.
NOAA’s Climate Prediction Center this month issued an ENSO El Niño alert for later this year. It could be the most intense on record.
(A) Kelvin wave that was initiated in January greatly increased the oceanic heat content to the largest March value in the historical record back to 1979
- NOAA Climate Prediction Center, 4/8/2014
ENSO stands for El Niño/Southern Oscillation. The easiest way to describe it is the Pacific Ocean is sloshing around back and forth like in a bathtub. It’s a natural phenomena occurring near the equator every few years in reaction to the coriolis effect.
Technically, El Niño occurs anytime the ocean near the equator is more than 0.5°C higher than normal. Right now from 180°-100°W longitude it’s nearly 6°C above normal.
A related opposite phenomena occurs when the equatorial Pacific drops more than 0.5°C below normal. It’s called La Niña.
El Niño/La Niña affect earth’s temperature
El Niño was first discovered by Peruvian fishermen in the 19th century. They noticed that fishing got bad when the ocean got hotter. But the rains also came and brought bountiful harvests to parched lands. Since it usually came in December they named it ‘El Niño’ after the Christ Child.
Increases in earth’s temperature in the 1980s and 1990s were dominated by El Niño events that culminated in the great El Niño of 1998. La Niña has dominated since then; earth’s surface temperature has stopped rising.
How does the Pacific Ocean ‘slosh’ around?
Most of the time, due to the rotation of the Earth, the prevailing equatorial Pacific trade winds blow west to east. Couple that with the coriolis effect and it piles the Pacific Ocean fully 18 inches higher in the tropics near Indonesia than it is in South American.
The movement of water from west to east draws cold water up from the deep ocean off the South American coast. In the tropics, though, the Pacific is compressed and warmed. Normally, the west Pacific Ocean at the equator is 30°C while South America is only 22°C.
At irregular intervals every few years the western Pacific forms a giant, slow-moving wave that washes back across the Pacific headed toward South America.
The wave is called a Kelvin wave. It’s like a mini, slow-moving tsunami that takes six months to cross the Pacific. It can’t be seen or felt at sea level, but can be measured by satellite.
The trade winds reverse direction, blowing now from west to east, when temperature and pressure gradients are strong enough. This alters climate patterns.
The Kelvin waves pushe all the warm water from the tropics eastward until it splashes up against Central and South America months later.
Then El Niño dissipates and the trade winds return back to normal to complete the cycle.
Climate Impacts of El Niño
An El Niño, like the one coming this winter, produce numerous global climate effects.
Heat invades Asia, southern Australia, Nova Scotia, southeastern Brazil and stretches from the U.S. Pacific Northwest all the way to the Aleutian islands. Drought hits southeastern Africa, Madagascar, Indonesia, Northern Australia and the eastern Amazon.
Wet weather, along with possible floods, could plague the region around Rio De Janeiro, central Africa and the American southwest. The U.S. Gulf coast gets both wet and cold.
As show above, the climate effects of El Niño in summer are very different.
The El Niño of 2014 is shaping up to be the most intense of the satellite era. NOAA reports a Kelvin wave has already formed and the trade winds, in fits and starts, have reversed direction. March produced the highest El Niño heat content ever measured so early in an ENSO event.
If things continue as they have been then global climate effects will be felt around the world by December.
The good news is an early result may be that the Atlantic hurricane season is milder than normal. As is, there hasn’t been a major hurricane stronger than Category 2 strike the United States mainland since 2005. That’s a record.
More good news. Texas and California may finally get relief from their devastating droughts. Unfortunately, it will come at the cost of droughts starting in other parts of the world.
2014 and/or 2015 may set records for warmest years yet. As a result, some will claim El Niño is caused by human activity. It isn’t.
‘Chicken Little’ environmental activists will loudly cry out that human-caused global warming has returned. They best beware. Strong El Niños are usually followed quickly by strong La Niñas, like happened after 1998 when earth’s temperature stopped rising.
Cry wolf to many times and people stop listening.