For snow lovers, El Niño is either a blessing bestowed from heaven or a curse issued by the satan himself– all depending on your north/south orientation. And while meteorologists continue to track this natural phenomenon and its effects on the global climate system– few have any real idea what actually triggers these “ENSO“ events.
A newly published study, which combines research from a global team of climate and chemistry scientists, indicates that El Niño events are likely triggered by especially large volcanic eruptions located in tropical latitudes such as the 1991 eruption of Mount Pinatubo in the Philipines.
“Stratospheric aerosols from large tropical explosive volcanic eruptions backscatter shortwave radiation and reduce the global mean surface temperature. Observations suggest that they also favor an El Niño within 2 years following the eruption.”
2-3 years after such an eruption, the chances of an El Niño event sky-rockets. But why? Shouldn’t the earth cool as high altitude aerosol’s block out more of the sun’s rays? Yes, the reasearchers all conclude that a cooler global temp is usually a direct result of such Volcanic eruptions but it’s what happens in the second year that counts.
4 out of the last 5 major tropical volcanic eruptions have led to a El Nino event two years later.
Ultimately, such volcanic eruptions are known to change the direction of dominant winds from Africa to central America. These particular winds largely dictate the global climate and after eruptions like Pinatubo, the winds near the equator become predominantly westerly. Ultimately, those warm minds sticking around the equator translate into warmer sea surface temperatures– thus triggering an El Niño event.
The findings are groundbreaking for long term climate forecasting. Instead of having a 6 month outlook on ENSO conditions, meteorologists and climate scientists might be able to predict El Niño up to two years out and for skiers/riders who will do anything for pow– knowledge is power.
Find the entire study here: Tropical explosive volcanic eruptions can trigger El Niño by cooling tropical Africa