The Pacific “cold tongue” is a cold ocean current flowing off Ecuador – Photo: shutterstock
Mystery of the Pacific Ocean “Cold Tongue”
For years, climate models have predicted that as greenhouse gas emissions increase, the oceans, including the Pacific Ocean, will warm.
However, the opposite is happening in one part of the Pacific Ocean. There is a stream of water extending thousands of kilometers from the coast of Ecuador in the east to the west which has cooled down for the last 30 years. Scientists call this stream of water a “cold tongue”.
The question is, will the cooling of this water ever stop, or will it suddenly turn into a hot state?
This is the most important question yet to be answered by climate science, said Pedro DiNizio of the University of Colorado Boulder (USA).
The Pacific Ocean is the largest, deepest ocean on Earth. Its surface area is more than the total land. Because of this, science is having a hard time understanding how it will respond to increasing greenhouse gases in the atmosphere.
Richard Seager of Columbia University in New York was one of the first to warn in 1997: The equatorial Pacific is cooling, a trend not observed in climate models.
Since then, data on sea surface temperatures have confirmed Mr Seager’s suspicions.
The eastern Pacific Ocean (closer to the Americas) is consistently 5–6 °C cooler on average than the western part of the ocean (closer to Asia). But between 1980 and 2019, this temperature difference increased by about 0.5 degree Celsius.
Wrong climate model?
Today, more and more scientists share Mr. Seager’s skepticism about the “cold tongue” temperature.
If climate models fail to reflect the “cold tongue”, they can be seriously misleading about climate.
“We need to figure out what that is,” said Isla Simpson at the US National Center for Atmospheric Research. This is really important because “cold tongues” will have a huge impact on Earth’s climate future.
Warm water in the western Pacific and cooler water in the east lead to more clouds over large parts of the eastern Pacific.
David Battisti of the University of Washington in Seattle says that more cloud strength means more sunlight is reflected. In other words, cooling of the eastern Pacific Ocean would slow down the rate of global warming.
According to climatologists, if the “cold tongue” continues to cool, it could reduce the level of projected global warming by up to 30% compared to what climate models predict.
It also means that the climate base state will be more like La Niña, increasing the risk of drought in the Horn of Africa and the American southwest – which also means permanent super-drought in the region. America.
On the other hand, if climate models do well and the eastern Pacific warms, the rate of global warming will be higher and there will be different regional effects.
At this point, the climate baseline will be El Niño-like, causing an increase in coral reef bleaching, making the Amazon hotter and drier; Australia and Indonesia are experiencing more droughts. Due to this, severe heat waves also occurred in India.
Meanwhile, more storms will hit parts of the US. In countries such as Peru and Ecuador, storms accompanied by heavy rains cause severe flooding and landslides.
Researchers first discovered the “cold tongue” in the 1990s, when they believed it to be a natural extreme diversity of the region.
Every change in this “cold tongue” has global implications. It could determine whether California suffers a long-term drought, or whether deadly wildfires engulf Australia, or the intensity of monsoons in India and the threat of famine in the Horn of Africa…
It may also alter the extent of climate change on a global scale with increased greenhouse gas emissions.
(Tagstotranslate) Pacific
