Climate change has generated an increase in marine heat waves in central Chile

Marine heat waves have increased in number and days in duration in the ocean off Central Chile due to climate changewhich will worsen if the El Niño phenomenon occurs, according to research associated with the Department of Geophysics of the University of Concepción.

These heat waves are extreme events in which the sea temperature rises above normal values ​​for at least 5 dayswhich can have direct impacts on marine ecosystems due to temperature increase or indirect ones, by modifying the exchange of gases and heat with the atmosphere, increasing the stratification of the layers of ocean water masses, which makes it difficult to mix of dissolved substances from the surface to deeper areas.

Specifically, the study by the UdeC geophysicist, David Carrascoreports that the largest event of this type, during the last 30 years, occurred from January 11, 1997 to March 8, 1998, lasting more than a year, with 4.5°C of heat above the average for the period (5.23 ° C maximum) and an extension of about 200 thousand square kilometers.

This marine heat wave is directly related to the great El Niño event of that year, the largest of the 20th century.

While, the second largest marine heat wave of the time occurred from October 22, 2016 to July 23, 2017, also above 4.5°C on average, with a duration of 275 days; it spread over an area of ​​170,000 square kilometers and the difference over the average temperature reached 3.46°C.

To the climatic event that triggered this heat wave It was called El Niño Costero.because it only affected the coasts of Peru and Chile.

According to the study developed together with the UdeC Geophysics oceanographer, Oscar Pizarrobetween 1982 and 2016 it has been detected that the number of days affected by marine heat waves has doubled and the forecasts for the end of this century indicate that the probability of generating these phenomena will be 16 times greater, considering the scenario “more optimistic” of warming by the end of the century of 1.5°C.

In addition, these heat waves will have a spatial extension that will be on average 21 times larger.

However, in a pessimistic scenario, that is, a 3.5°C increase by the end of the century, the number of marine heat waves would more than double.

While the spatial extension would be four times greater than in the case of an increase of 1.5°C. Likewise, these natural events would triple their duration and double their maximum intensity.

But in addition to climate change, the El Niño Phenomenon would also have an impact on the increase in these heat waves, by generating warmer years than the average. These warm temperature anomalies, which originally spread along the Equator Line once they reach the coast of South America, continue to travel along the coasts of Peru and Chile contributing to the generation of marine heat waves in these areas. zones.