Tonga and Toba eruption

Summary

The provided content discusses the Tonga volcanic eruption in January 2022 and compares it with the Toba supervolcano eruption approximately 74,000 years ago, highlighting their impacts and the implications of the latter on human evolution.

Abstract

The recent eruption of a volcano on Tonga Island on January 15th, 2022, was a significant event heard as far away as Fiji, causing widespread concern due to the dramatic images of smoke and ash clouds before the island's communication cable was severed. This event is juxtaposed with the ancient Toba eruption, which occurred around 74,000 years ago in present-day Indonesia. The Toba event was monumental, releasing 1,700 cubic miles of rocks and covering the region with volcanic debris, leading to a volcanic winter that caused a global temperature drop. Climate simulations suggest varying degrees of cooling across the hemispheres, with the Northern hemisphere experiencing more severe effects. These findings are particularly relevant to Stanley Ambrose's theory, which posits that the Toba eruption led to a bottleneck in human populations, resulting in low genetic variability among modern humans, who are believed to have descended from a small group of survivors in Africa.

Opinions

The Tonga eruption was a major event, with its effects felt over a large distance, and it captured global attention before communication was lost.
The Toba eruption is considered the largest in the last 28 million years, with its impact on the climate and environment being severe and far-reaching.
Researchers believe that the Toba eruption could have caused a significant decline in global temperatures, with varying effects across different regions.
Stanley Ambrose's theory suggests that the Toba eruption may have been responsible for a population bottleneck in human ancestors, supporting the idea of a common ancestor for modern humans and their relatively low genetic diversity.
Despite the severe climatic effects of the Toba eruption, it is argued that the event did not significantly impact the development of hominid species in Africa, contradicting the notion that it led to near-extinction events for humans outside of Africa.

Two eruptions in different times

A volcano erupted on Toga Island on 15th January after being active — minor explosions — in the days before the January 15th explosion. The explosion was heard as far as Fiji (400 miles away). The earth rumbled as magma, smoke, ash came out of the volcano, and the explosion thrust plumes of smoke and ash into the atmosphere.

Early images of the eruption showed clouds of smoke rising from the volcano. The whole world gawked at the eruption before the lone cable connecting Tonga to the world snapped. It only left people to speculate the fate of the islands circling the volcano.

Early reports showed rocks showering on the island; what goes up will come down, says the gravity. Rocks would have been hurled up into the atmosphere: thanks to the force of the eruption, but then at some point, gravity overcame the eruption force and hence, the shower.

Toba eruption

Around 74,000 years ago, another volcano erupted: the Toba eruption. A volcano erupted on the island of what we now call Sumatra (Indonesia). The Toba eruption was the biggest in 28 million years.

The eruption covered parts of Indonesia, India and the Indian Ocean with 15 centimetres (6 inches) of volcanic debris. Researchers opine that 1,700 cubic miles of rocks equal to 3 million Empire State buildings were emitted from the volcano.

The ash and volcanic gases released by the eruption led to a volcanic winter: it partially blocked sunlight. Temperatures globally dopped by 3 to 5 degrees.

Research through climate simulation has assessed how the Toba explosion affected the climate globally. Researchers came out with 42 climate model simulations, varying parameters in each simulation: magnitude of volcanic emissions, time of year of explosion.

Stanley Ambrose theory

And these simulations were important in the context of Stanley Ambrose theory. The theory links Toba explosion and low genetic variability.

Around 74,000 years ago human population declined. The theory states around 74,000 years ago humans, in Asia and Europe didn’t survive, but a few small groups of humanoids in Africa did survive. Therefore, humans have a common ancestor and have low genetic variability.

But the climate simulation estimated cooling in the northern hemisphere of at least 4 degrees, with a few places seeing 10 degrees fall in temperature.

In contrast, the Southern hemisphere was relatively less affected. Even considering the worst eruption scenario, cooling in the Southern hemisphere didn’t exceed 4 degrees. However, parts of Southern Africa and India would have received less rainfall.

Researchers have concluded that the Toba eruption didn’t have a significant impact on the development of hominid species in Africa.