Blown into an El Niño year… What does it mean?
El Niño, as defined by the National Oceanic and Atmospheric Association, is “a naturally occurring climate pattern associated with warming of the ocean surface temperatures in the central and eastern tropical Pacific Ocean,” and its impacts as a weather cycle expand far beyond the Pacific, impacting weather patterns and ocean life worldwide.
El Niño, which translates to “the little boy” in Spanish, was first observed by indigenous Peruvian fisherman who noticed a change in the water’s temperature in a cyclical manner; the weather pattern was granted its formal name by Spanish Conquistadors, and “El Niño” has stuck ever since.
El Niño is caused by a shift in wind patterns. Usually, a westward-blowing wind (known as a trade wind) will cause warmer water to be blown away from the northern South American coast towards Indonesia. During El Niño, these winds weaken, and the changes in air pressure causes the warmer water to flow back across the Pacific towards South America. As a result, convection (transfer of heat through liquids or gasses) above the abnormally warm surface water causes a sharp increase in precipitation, and changes the regular weather pattern.
What makes El Niño so interesting is that it is not a predictable cycle, meaning it comes and goes at inconsistent intervals. However, generally it is present for two to seven years at a time. Furthermore, El Niño is so impactful because it disrupts the global atmospheric circulation. Global atmospheric circulation is the large-scale movement of air that distributes thermal energy in the form of heat across the surface of Earth. As a result, colder longer winters strike the Pacific Northwest, monsoons in India weaken, and Sub-Saharan Africa experiences drastic increases in precipitation.
According to National Geographic, “El Niño events are indicated by sea surface temperature increases of more than 0.9° Fahrenheit for at least five successive three-month seasons. The intensity of El Niño events varies from weak temperature increases (about 4–5° F) with only moderate local effects on weather and climate to very strong increases (14–18° F) associated with worldwide climatic changes.” These impacts are felt varyingly far and wide, as precipitation will drastically increase on the western South American coast, while dry seasons strike down on most of Indonesia and Australia.
As observable as El Niño is now in our lives, climate records of it have dated back millions of years. Embedded within ice cores, sediment samples buried deep within the sea, chemical compositions of cave rocks, and tree rings, paleoclimatologists (scientists who study the climate from thousands of years ago) have been able to extract an extensive record proving El Niño’s existence as an established weather pattern.
El Niño has started this year in 2023, and its impacts on the globe will range from new record temperatures (as overall global temperatures are higher during El Niño years), extreme rainy seasons in the American West (which will prompt flash floods, given the past decade of drought-like conditions have decreased the water retention rates of the ground), and cause the East to face drier weather (exacerbating already harmful wildfires raging across Central and Eastern Canada).
This incredible weather pattern has impacts reaching far and wide, and having a better understanding of how weather patterns shift is the first step for climatologists to understand how they can change and impact humanity as climate change escalates.
Justin
Cover Image: NOAA