Water vapor released by volcano eruption near Tonga could warm Earth even further
It has now been more than 8 months since the volcano Hunga Tonga-Hunga Ha’apa near to Tonga erupted. Today, scientists continue to study the possible impacts of this event on our planetand lately they discovered that the water vapor released by the eruption could raise the Earth’s global temperature.
According to the calculations made by the researchers, the volcano released approximately 45 million tons of water vapor in the atmosphere in addition to ash and volcanic gases. This huge amount has increased the humidity of the global stratosphere by about 5% and could trigger a stratospheric cooling cycle accompanied by a surface-level warming. According to the scientists, these effects could persist in the coming months.
The eruption of the Hunga Tonga-Hunga Ha’apa volcano began on January 13, but the intensity of the phenomenon peaked two days later. The explosion spread over 260 km and sent ash, steam and gases up to an altitude of 20 km. It was the most powerful eruption on Earth in several decades.
The peculiarity of an underwater eruption
Generally, large volcanic eruptions tend to cool the planet by sending sulfur dioxide into the upper layers of the atmosphere. This substance filters solar radiation. Additionally, ash and rock particles can also lower the temperature temporarily by blocking the Sun’s rays. Millions of years ago, massive volcanic activity on Earth could have led to climate change and mass extinctions.
According to estimates, the volcano near Tonga ejected in the 400,000 tons of sulfur dioxidei.e. 2% of what the Mount Pinatubo in the Philippines ejected in 1991. But unlike Mount Pinatubo, whose eruption caused global temperatures to drop by around 0.5°C for a year, the Hunga Tonga-Hunga Ha’apa submarine volcano sent “substantial amounts of water” in the stratosphere. The latter is the layer of the atmosphere between altitudes 6 to 20 km and 50 km.
According to the scientists behind the new study, underwater eruptions can derive much of their explosive energy from the interaction between water and high-temperature magma. This propels large amounts of water and steam into the eruption column.
The effect of water vapor
The water vapor in the atmosphere absorbs solar radiation and returns it as heat. According to scientists, with tens of millions of tons of moisture coming from the Tonga volcano into the stratosphere, the surface of the earth will warm up. However, the study does not say by how many degrees Celsius.
Because water vapor is lighter than other volcanic aerosols, and also because it is less affected by the force of gravity, this warming effect will take time to dissipate. Surface warming could thus continue for several months.
Aside from the increase in surface temperature, the researchers behind the new study also determined that the huge amount of water in the stratosphere could alter the chemical cycles that control stratospheric ozone. However, other more detailed studies will be necessary to quantify the effect of the quantity of water on that of ozone.