The eastern Pacific Ocean has a current that is getting colder, contrary to climate models predicted by scientists.
The Mystery of the Pacific “Cold Tongue”
For many years, climate models have predicted that as greenhouse gas emissions increase, ocean waters, including those in the Pacific, will warm up.
However, in a certain region of the Pacific, the opposite is occurring. Stretching thousands of kilometers from the coast of Ecuador in the east flowing westward, there is a current that has been cooling for the past 30 years. This current is referred to by scientists as the “cold tongue.”
The pressing question is when will this cooling process stop, or will it suddenly shift to a warming state?
Pedro DiNezio from the University of Colorado Boulder states that this is the most crucial question that climate science has yet to answer.
The Pacific is the largest and deepest ocean on Earth. Its surface area is larger than all the landmasses combined. Consequently, scientists face significant challenges in understanding how it will respond to the increasing greenhouse gases in the atmosphere.
“The Cold Tongue” of the Pacific is a cold ocean current flowing from Ecuador – (Photo: SHUTTERSTOCK).
Richard Seager from Columbia University in New York was one of the first to warn in 1997 that the equatorial Pacific was cooling, a trend not observed in climate models.
Since then, data on sea surface temperatures have confirmed Seager’s suspicions.
The eastern Pacific (near the Americas) has always been colder on average compared to the western part of the ocean (near Asia) by 5 – 6°C. However, from 1980 to 2019, this temperature difference has increased by about 0.5°C.
Are Climate Models Misleading?
Today, more and more scientists share Seager’s concerns regarding the temperature of the “cold tongue.”
If climate models do not accurately reflect the “cold tongue,” they could lead to serious misunderstandings about climate dynamics.
Isla Simpson from the U.S. National Center for Atmospheric Research states: “We need to understand what it is.” This is truly important because the “cold tongue” will have significant impacts on the future climate of the Earth.
The warming waters in the western Pacific and the colder waters in the eastern Pacific result in more clouds over vast stretches of the eastern Pacific.
David Battisti from the University of Washington in Seattle explains that increased cloud cover means more sunlight is reflected. In other words, the cooling of the eastern Pacific will slow down the rate of global warming.
According to climate scientists, if the “cold tongue” continues to cool, it could reduce the expected rate of global warming by up to 30% compared to predictions from climate models.
This also means that the fundamental state of the climate will resemble La Niña, increasing the risk of drought in the Horn of Africa and the Southwestern United States—potentially leading to persistent extreme droughts in the U.S.
On the other hand, if climate models are accurate and the eastern Pacific warms, the rate of global warming will be higher, leading to various regional impacts.
In this scenario, the fundamental state of the climate will resemble El Niño, increasing coral bleaching events, causing the Amazon to become hotter and drier; leading to more droughts in Australia and Indonesia, while also resulting in severe heatwaves in India.
Meanwhile, regions in the Americas would experience more storms. Storms accompanied by heavy rainfall could lead to severe flooding and landslides in countries like Peru and Ecuador.
Researchers discovered the “cold tongue” for the first time in the 1990s, initially considering it an extreme natural variation of the region.
Any changes in this “cold tongue” have global significance. It could determine whether California faces persistent drought, or if deadly wildfires engulf Australia, or influence the intensity of the monsoon in India and the risk of famine in the Horn of Africa…
It may even alter the extent of global climate change amidst increasing greenhouse gas emissions.
