The Hunga Tonga-Hunga Ha’apai volcano erupted in January causing towering ash clouds and tsunami waves across the islands of Tonga.
The event was the volcanic equivalent of a ‘near miss’ asteroid whizzing by the Earth, the largest since Mount Pinatubo in the Philippines blew in 1991, and the biggest explosion ever recorded by instruments.
According to scientists, there is a one in six chance that an eruption of a similar magnitude could happen again this century — and we are not ready for it.
Writing in the journal Nature, British researchers say the world is ‘woefully unprepared for such an event’, which could have ‘repercussions for supply chains, climate and food resources worldwide’.
The giant undersea volcano eruption resulted in a tsunami warning being issued by the Pacific nation of Tonga. The 11-hour-long blast created tsunamis that reached Japan and North and South America.
Ash fell over hundreds of kilometres, affecting infrastructure and agriculture. The damage caused amounted to 18.5% of Tonga’s gross domestic product. Submarine cables were severed, cutting off Tonga’s communications with the outside world for several days.
Researchers have said that the Tongan eruption should be a wake-up call as data from ice cores suggest that the probability of an eruption with a magnitude of 7 (10 or 100 times larger than Tonga) or greater this century is 1 in 6.
‘Eruptions of this size have, in the past, caused abrupt climate change and the collapse of civilizations, and have been associated with the rise of pandemics,’ said the study.
Over the next century, large-scale volcanic eruptions are hundreds of times more likely to occur than asteroid and comet impacts, put together. The climatic impact of these events is comparable, yet the response is vastly different.
The impact of such events would disrupt transport, food, water, trade, energy, finance, and communication.
The study criticised the funding into ‘Planetary defence’ mechanisms like Nasa’s Double Asteroid Redirection Test (DART) mission to protect us against future asteroids.
‘By contrast, there is no coordinated action, nor large-scale investment, to mitigate the global effects of large-magnitude eruptions. This needs to change,’ said the researchers.
The last magnitude-7 event was in Tambora, Indonesia, in 1815, resulting in the death of around 100,000 people due to volcanic flows, tsunamis, the deposition of heavy rocks and ash on crops and houses, and subsequent effects.
Globally, temperatures dropped about 1 °C on average, causing the ‘year without a summer’. The eastern United States and much of Europe endured mass crop failures, and the resulting famines led to violent uprisings and disease epidemics.
Scientists have warned that due to changes in ocean and atmospheric circulation caused by climate change, a large-magnitude eruption in the tropics could cause 60% more cooling in the next century compared with today.
For context, the world is already around 1.1 °C warmer than in the pre-industrial era. So, the impact of a large volcanic eruption would be abrupt and immense, with uneven effects on weather, rainfall and temperature.
The financial losses will be massive, running into the multi-trillions. Given the estimated recurrence rate for a magnitude-7 event, this equates to more than US$1 billion per year.
The study called for increased attention to research aimed at forecasting, preparedness and mitigation of volcanic events.
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