Huge swath of Atlantic Ocean cools at record speed, alarming scientists

Until March, the central Atlantic was experiencing its warmest weather event since 1982, with temperatures reaching 30 degrees Celsius. But this was followed by a major temperature swing, with surface water temperatures dropping below 25 degrees Celsius.

Currently, scientists are monitoring a strip of water that extends a few degrees on either side of the equator between Brazil and the coast of East Africa.

They explained that it is not only a matter of the decrease in temperature in this region, known as the central tropical Atlantic Ocean, but also the speed of change.

The central tropical Atlantic Ocean goes through its own temperature cycle each year, reaching its highest points in March and April before cooling in the summer.

But, starting in June, surface water temperatures began to drop at an unprecedented rate.

By mid-June, temperatures in that area were 0.5-1.0°C cooler than average for that time of year.

Now, water temperatures are starting to rise back towards normal levels.

In general, the cool summer waters in the Atlantic Ocean are associated with stronger trade winds blowing over the equator, which cause warm surface water to be swept into the cold deep waters, where it rises to the surface in a process called equatorial upwelling.

But winds in the region, which is experiencing rapid cooling, were weaker than usual this year.

Michael McFadden, of the National Oceanic and Atmospheric Administration (NOAA), said that while climate change cannot be ruled out as the cause, it is unlikely to be responsible.

Scientists have suggested that the event is likely linked to the onset of the Atlantic La Niña phenomenon. Like the El Niño and La Niña phenomena in the Pacific Ocean, the Atlantic La Niña represents extreme peaks and troughs in the warming and cooling cycles of the ocean.

If water temperatures remain below average for 3 months, this would be enough to classify the situation as a La Niña Atlantic, something that has not happened since 2013. This is a worrying issue, because La Niña Atlantic events can have wide-ranging impacts on nearby weather systems.

“The decrease in rainfall over the Sahel, the increase in rainfall over the Gulf of Guinea, and the seasonal shifts of the rainy season in northeastern South America are all attributed to La Niña Atlantic events,” said Dr. Franz Tuschen, a scientist at the National Oceanic and Atmospheric Administration.

In 2012, Brazil experienced severe drought in the northeast of the country, and floods in the Amazon region, coinciding with cold Atlantic waters.

The 2013 Atlantic La Niña event was followed by devastating flooding in large areas of Brazil, including Rio de Janeiro.

Source: Daily Mail