Global warming has reduced the world's oceans' ability to limit volcanic winter. Now it can give a much greater "killer effect" than before.
Researchers from the United States have found that our planet is becoming increasingly vulnerable to major volcanic eruptions. Global warming is increasing the difference in temperatures between different layers of the ocean, and it can no longer effectively act as a "heat storage". A related article was published in Nature Communications.
The authors of the new work simulated the eruption of the Indonesian volcano Tambora (1815) in the conditions of 2085. Such eruptions occur approximately once every 270 years, which determined the choice of 2085 as the date of the next event. It turned out that due to warming, the upper layers of the ocean in our time have become so much warmer than the lower ones that the former mechanisms of inhibition of the volcanic winter no longer work.
In 1815, Tambora threw out a huge amount of sulfur into the stratosphere, which formed sulfur aerosols there. They increased the amount of sunlight reflected by the Earth into space, significantly cooling the planet. This caused a "year without summer" - heavy snowfalls were in New York and Canada even in June.
However, in the 19th century, the ocean partially compensated for the cooling of the planet caused by the volcano. When the upper layers of sea water cooled, they sank down, and from there, less cold water masses rose. In the 21st century, as modeling has shown, this will not work. The upper layers of the seas are so warm that they will cool much longer before they have to sink down. Therefore, the eruption of the Tambora class will drop the average annual temperatures on the planet by 1.1 degrees Celsius.
At first glance, this does not seem like a big problem. Warmer sea waters will prevent temperatures from dropping below normal for the 20th century. But in fact, this will feel extremely painful in 2085: because of global warming, everyone has long been unaccustomed to harsh winters. In addition, a volcanic winter from a new major eruption stronger than in 1815 will reduce the evaporation of water from the sea surface. This will lead to drought in many regions of the world at once, because rain is formed precisely from water evaporating from the seas. Such a drought will significantly reduce harvests across the planet and lead to hunger.
IVAN ORTEGA