El Niño Builds in Pacific Ocean

As delegations converge on Bonn, Germany ahead of the latest round of UNFCCC climate talks, another strong El Niño has been forecast. Research suggests global warming could strengthen the event, which has significant implications for fish distribution and rainfall across the Pacific basin and may even be linked to the record flooding now seen in Texas and Oklahoma.

US National Oceanic and Atmospheric Administration data show that combined land and sea surface temperatures in April alone were 0.74 degrees above the 20th century average, while sea-surface temps in the same period stand out as the warmest since 1880, surpassing the previous high set in 1998 during a so-called “super El Nino” event.

The phenomenon is characterized by unusually warm temperatures (La Niña event means unusually cool temperatures) and was first described by fishermen off Peru as the arrival of unusually warm water. El Niño, means “little boy” in Spanish—so named because the even often began around Christmas.

During an El Niño event, westward-blowing trade winds weaken along the Equator. A resulting differentiation in pressure and wind speed causes warm surface water to shift eastward from the western Pacific and toward South America.

As warm water builds along Ecuador, Peru, and Chile it prevents the upwelling of nutrient-rich colder water that is critical to a productive marine ecosystem. Fish populations tend to die or migrate, further harming stocks already under pressure from overfishing and leaving the catch out of reach for many island communities.

El Niño can also produce severe changes precipitation—inundating areas that are typically arid with rainfall and causing droughts in places that depend on seasonal monsoons for agriculture and drinking water.



Sources: NOAA, National Geographic, WikiCommons

Fisherman photo: ABC.net