Tonga eruption may be causing this unexpected ozone hole

According to #CopernicusAtmosphere data, the 2023 ozone hole is starting to form earlier than in 2021 and 2022, in line with the forecast.

Read more & stay tuned for more #OzoneInsights in the coming days
👉https://t.co/ImkHEP5yMI pic.twitter.com/xD0ch4ud4Q

— Copernicus ECMWF (@CopernicusECMWF) August 4, 2023

Typically, the ozone hole begins forming towards the end of September, peaks in October and closes by November or December.

The Antarctic ozone hole is a recurring thinning of the ozone layer in the stratosphere, comprised of ozone molecules that absorb harmful ultraviolet radiation from the sun. 

Over time, the ozone hole has gradually recovered due to international efforts, including the 1989 Montreal Protocol that significantly reduced ozone-depleting chemicals.

However, the eruption of the Hunga Tonga-Hunga Ha'apai volcano on January 15, 2022, released an extraordinary amount of water vapor into the stratosphere, disrupting the natural ozone-regulating processes. 

The authors explained in their paper that this influx of water vapor resulted in ice clouds forming, facilitating the accumulation of ozone-depleting molecules.

They highlighted their concern about the potential impact of the ozone hole on Antarctic sea ice, which has reached record lows in recent years. 

The increased penetration of UV radiation through the weakened ozone layer could contribute to ice melt and further warming of the Southern Ocean.

Jucker noted that increased UV radiation reaching Antarctica and the Southern Ocean has more energy for ice melting. The ocean turns dark blue instead of reflective white with reduced sea ice. 

“There is a risk that the Southern Ocean would then heat up even more and then indirectly melt more ice because the water next to the ice is warmer," he said. 

The Tonga Volcano

The eruption of the Tonga volcano is expected to have lasting impacts, including higher surface temperatures in various regions of the world.

While this effect is temporary compared to the long-lasting impact of greenhouse gas emissions, the study highlights the interconnectedness of natural events and climate change.

As scientists monitor these developments closely, the early formation of the ozone hole serves as a reminder of the delicate balance between various atmospheric factors and their influence on the environment and climate.

The complete study was published in ESS Open Archive on August 4 and can be found here.

Study abstract:

The amount of water vapor injected into the stratosphere after the eruption of Hunga Tonga-Hunga Ha'apai (HTHH) was unprecedented, and it is therefore unclear what it might mean for surface climate. We use climate model simulations to assess the long-term surface impacts of stratospheric water vapor (SWV) anomalies caused by volcanic eruptions. The simulations show that the SWV anomalies lead to strong and persistent warming of Northern Hemisphere landmasses in boreal winter, and austral winter cooling over Australia. Thus, SWV forcing from volcanic eruptions like the one from Hunga Tonga-Hunga Ha'apai can have surface impacts on a decadal timescale. We also emphasize that the surface response to SWV anomalies is more complex than simple warming due to greenhouse forcing and is influenced by factors such as regional circulation patterns and cloud feedbacks. Further research is needed to fully understand the multi-year effects of SWV anomalies and their relationship with climate phenomena like El Niño Southern Oscillation.