Q&A: Seasons Turned Upside Down, What is the El Niño Effect?

On the east coast, flowers could be seen blooming in December.

If you are celebrating the warmer temperatures and uncharacteristic winters, thank El Niño. If you’re complaining about the cancellation of your skiing and snow tubing trips, blame El Niño. The force behind the odd weather, El Niño is an aberration of ocean currents that affects atmospheric patterns, causing unexpected climatic changes.

As you might notice at the beach, the world’s ocean waters are in constant motion. In fact, they follow systematic, predictable trajectories in the form of currents, which are caused by wind forces and differences in water density at different locations. Normally, ocean currents in the Pacific Ocean carry warm water from the west coast of Latin America towards Australia and Southeast Asia. These currents are driven by trade winds – a pattern of surface winds that follow constant trajectories – and they make the Asian and Australian side warmer and wetter while keeping the Latin American side cooler and drier.

During El Niño years, trade winds weaken, and the warm water accumulated near Southeast Asia and Australia swamps east. The Latin American and Californian coasts become wetter and warmer. Around the world, El Niño has been associated with dry forest fires in Indonesia, droughts in southern Africa, mitigation of the Indian monsoon, and flooding in the tropics.

The 2015 El Niño is arguably the strongest recorded in human history, and although it is a natural phenomenon, the science behind it is not completely clear. Thus, the recent increased frequency of Super El Niño events and their possible association with global warming have become the basis for future research.