The ingredients needed for another huge El Niño event are already in the pot for this coming summer. It will reach its climax throughout the winter, and possibly not end until spring 2015. Weather experts, such as meteorologist Eric Holthaus, have already been keen to start building awareness. Recently, Eric wrote an informative article that brings attention to how El Niño affects us on an individual level, jumpstarting the internet’s interest on the topic once again.
Simply put, El Niño (as well as its counterpart, La Niña) create weather extremes that hurt our ecosystem and economy. For the West coasts of North and South America, this means increased precipitation, and during the winter, more storms. Though no one can refute that the state of California is in dire need of more rainfall, this increase is not in balance. An excess of rain after a drought can lead to flooding, mudslides, loss of crops and lives. For the majority of the world El Niño will cause drought (refer to fig. 1). This will lead to devastating wildfires, extreme heat, and again, the loss of crops and lives. Most unfortunate, many developing nations are in the areas that get the worst of it.
As important as it is to hear about the devastation El Niño causes, it’s also vital to understand the following: what exactly this phenomenon is; what causes it to occur; how we can better predict its coming; and what we can do to help put the brakes on its growing frequency and intensity. During my research I garnered a deeper knowledge that is part enlightening, very unsettling, and of great importance to share.
A Brief History
The El Niño phenomenon was first discovered in the 17th century, though we don’t know how long before then it had already been occurring. The name El Niño, “The Christ Child”, originates from South American fishermen who first discovered the event at its peak, around Christmas. El Niño is the name given to the warmer than average sea surface temperature, which occurs in the equatorial region of the Pacific ocean, spanning from the coast of Ecuador and Peru, to about Tahiti. This is a huge distance, wider than North America!
The tracking of El Niño became more methodical by the beginning of the 20th century. In the 1920s, British scientist Sir Gilbert Walker first discovered that atmospheric pressure and wind circulation changed drastically around the world every few years. He invented terms for those climate oscillations, and for the region between Tahiti and Darwin, Australia it is called the Southern Oscillation. The term ENSO refers to the combination of El Niño and the Southern Oscillation.
How El Niño Functions
In normal conditions, the thermocline in the equatorial Eastern Pacific is closer to the surface of the ocean. This allows for the upwelling of cold water, which is crucial for replacing the nutrient-depleted warm water at the surface. During an El Niño event, a giant underwater wave of warm water crosses the ocean and pushes the thermocline in the Eastern Pacific much deeper than it should be. Ocean life stagnates, and the fishing industry (a large part of the South American economy) takes a huge hit.
The trade winds are also affected by El Niño, which in turn worsen El Niño’s state. The above average heat that transfers into the atmosphere disperses the barometric pressure, weakening the trade winds. Precipitation that should be carried across the Pacific gets stuck in the centre, sometimes even reversing, if the westerly winds overpower. Warm water piles in the East, sinking the thermocline even further down.
Detection and Prediction Systems for El Niño
Observation systems for ENSO have only been in place since 1985. ENSO observations cover four regions in the equatorial Pacific. An El Niño event is confirmed when the Niño 3.4 region (in the central Pacific) has five consecutive SST anomalies happen in a 3 month period. The ONI tracks this standard of measurement.
The TOGA program and its buoy array, the TAO project, collect information in a plethora of ways. Scientific research ships track the tropical ocean atmosphere and upper oceanic layer, while radiosondes monitor the atmosphere and weather patterns worldwide. Satellites track tropical rainfall, wind, and ocean temperatures. Lastly, different types of buoys (drifting, moored, and expandable) observe upper ocean and sea surface temperatures. Supercomputers process these data-sets to allow for real-time monitoring.
There is a lack of density in the atmospheric pressure data being collected. Subtle variations in pressure, even up to a year before an El Niño event occurs, could aid in creating more solid prediction models. Currently, there are three types of prediction models: Hydrodynamic coupled ocean-atmosphere models, statistical models, and a hybrid of the two. One of the factors limiting predictability, though, is the effects of high-frequency atmospheric variability. Small miscalculations in the initial conditions may cause big changes in the results of an El Niño forecast.
Increasing the density of atmospheric pressure data through more sensors would be a game changer. Not only would the increased data be valuable to detect big weather events such as El Niño, but can also act as an early warning system for hurricanes and typhoons.
Our Effect on El Niño
El Niño has been occurring for centuries, taking approximately 3-7 years for the ocean to be ready for it to occur once again. Considering we don't know when it originated, this weather phenomenon seems to be a natural part of the ocean’s cycle. However, the effect that the industrial revolution (and subsequently increased global warming) is having on El Niño is yet to be fully determined, but the combination isn’t looking promising for our future.
Some scientists believe that the warming ocean temperatures, brought on by the spike in heat-trapping CO2 (and other greenhouse gases) in our atmosphere, will only intensify and increase the frequency of El Niño. The rise of greenhouse gases means that more long-wave radiation is getting trapped in our atmosphere than should be, further feeding an El Niño event. Kent Trenberth, a climatologist at the Colorado-based National Center for Atmospheric Research theorizes that El Niño is becoming the coping mechanism that the Southern Oscillation has resorted to in order to release the rising amount of excess heat from the tropics.
The state we have put our precious earth in is inexcusably and embarrassingly dire. We all need to take responsibility, on every level from personal to government to corporate. The poisonous soup that El Niño and global warming are cooking up is just one of the huge threats we have thoughtlessly and greedily concocted in a mere two centuries. Take action! Be a part of the solution, else we have already lost.