Spike in water temperatures evidence of ‘irreversible’ El Nino

by Alicia Villegas on 27 Jun 2014 Water temperatures in the equatorial Pacific Ocean rose drastically last week, prompting expectations of an upward warming trend that would confirm the development of El Nino.

Sea surface temperature (STT) anomalies in the Nino 3.4 region (see image below) showed the highest value of the year at +0.9ºC on June 20, according to data from NOAA seen by Undercurrent News.

This is important to define the event as El Nino since scientists classify the intensity of the weather phenomenon based on STT anomalies exceeding a pre-selected threshold in a certain region of the equatorial Pacific.

The most commonly used region is the Nino 3.4, and the most commonly used threshold is a positive STT departure from normal, greater than, or equal to +0.5°C.

Thus, NOAA defines El Nino as five consecutive overlapping 3-month periods at or above the +0.5°C anomaly in the Niño 3.4 region.

The growth of temperature anomalies from +0.4°C in mid-April to +0.9°C now has encouraged projections of an upward warming trend confirming the development of El Nino.

'This is a big jump in temperature, from now on waters will hardly be cooled, the event is irreversible,' oceanic scientist Luis Icochea told Undercurrent.

Icochea, who in April said that abnormally high temperatures were reminiscent of 1997-98 – when took place one of the strongest El Nino’s ever – is confident El Nino will develop this year.

'Everything suggests El Nino will be very strong, without ruling out the possibility of an extraordinary event,' Icochea said.

Abnormalities of sea surface temperature in Peru have been noticed already in May, as anchovy has moved to the south, near the shore, where industrial fleet is not allowed to operate.

In the north-center area — with a first anchovy season’s TAC of 2.53 millon metric tons — industrial fleet is seen poor catches so far.

By June 11, industry players said only 36% of the anchovy’s total allowable catch had been caught.

'Fishmeal players in Peru will be the most harmed by El Nino, as anchovy is the resource most affected by the weather event,' Icochea said.

To avoid the increased temperatures, pelagic fish such as anchovy will have to move to cooler, deeper waters where feed is available and there are suitable oceanographic conditions.

On the other hand, the phenomenon could mean higher catches of other species for human consumption such as hake — which is showing already a biomass improvement — tuna, mahi mahi, swordfish or shark, Icochea said.