The Hunga-Tonga-Hunga-Ha'apai volcano erupted without warning. Mere Taufa thought bombs were going off in the city of Nuku'alofa. The afternoon sky darkened as a cloud of smoke and ash rose 12 miles into the sky. "You could just hear screams everywhere," says Mere. "People screaming for safety, for everyone to get to higher ground."

Tongan people knew that volcanic eruptions can trigger tsunamis. Soon huge waves were hitting the coast. One woman, Angela Glover, was swept away and drowned. Her husband survived by clinging to a tree.

Hours later, waves flooded car parks on the coast of California. In Japan 230,000 people were told to leave their homes.

Warnings were also issued in New Zealand, Australia, Hawaii and Alaska. Shock waves were registered 10,000 miles away in Britain.

Last September an eruption in the Canary Islands destroyed 200 homes. On Wednesday the Wolf Volcano in the Galapagos Islands erupted. 

In 1815 Mount Tambora in Indonesia threw so much ash into the atmosphere that it in some places it blotted out the sun. Temperatures fell and crops failed. Some called 1816 "The Year Without a Summer". 

But now some scientists believe volcanoes could help us fight climate change.

In 1991, the eruption of Mount Pinatubo in the Philippines released millions of tons of sulphur dioxide into the atmosphere. These created tiny drops of moisture that scattered the sun's rays and reflected some of them back. As a result, the Earth's average temperature fell by 0.5C the following year.

It is possible that other volcanoes could have the same effect if we find ways to make them erupt. 

This could have a big impact. Brentan Alexander notes: "Geoengineering would allow mankind to avoid the worst impacts of climate change by adding planet-wide cooling technology to our toolset."

The drawback is that sulphur aerosols can damage the ozone layer, and return to the surface as acid rain. And if too many were released, we could experience another "Year Without a Summer".

But, says Brentan Alexander, as climate problems grow more severe, it could become our "least bad" option.

Yes: Climate change is a critical problem and anything that might halt it is worth trying. If one volcano can lower Earth's temperature by 1C, a few eruptions could solve all our problems.

No: Volcanoes are incredibly dangerous, in terms of both the lava and ash they produce and the tsunamis they can trigger. Causing an eruption could have terrible consequences across the world.

Or... We should try to mimic the effects of a volcanic explosion without actually causing one. We could disperse sulphur dioxide high up in the stratosphere just as Mount Pinatubo did.