We now know why La Niña lasted 3 years

The La Niña climate phenomenon is currently coming to an end after an exceptional three-year period. A triple La Niña is not unprecedented in the history of weather, but such a duration remains surprising in this context of global warming. La Niña is characterized by a cooling of part of the waters of the Pacific, a phenomenon which then impacts the global climate in different ways, by mitigating the global heat. THE National Center for Atmospheric Research (NCAR) thinks they’ve found the reason La Niña lasted so long. Posted in Science Advancesthe study explains that the smoke from the 2019-2020 Australian fires managed to cool the waters of the Pacific located several thousand kilometers from the flames.

Fires can cool the climate, like volcanic eruptions

The fact that a major geological event, such as a volcanic eruption, could cool the climate was already well known to scientists. But it would also seem that the largest forest fires in the world, such as those in Australia, can have the same impact, and thus cool certain areas of the globe. Recall that the fires of 2019-2020 had burned 18 million hectares.

The smoke from the fires had surrounded the entire southern hemisphere, without reaching the upper atmosphere, unlike volcanic ash. The smoke from the fires, on the other hand, succeeded in influencing the weather by modifying the circulation of the winds. And it is precisely the direction of the winds that modifies the ocean currents and then allows the waters of the Pacific to cool, leading to the La Niña phenomenon.