Fears of volcanic winter as Earth erupts

Apocalyptic scenes: Villagers flee nature’s fury © PA

This weekend saw tragedy unfold as Indonesia was devastated by a volcanic eruption. An isolated disaster or worse to come? Scientists remain uncertain.

Terror struck Sumatra on Saturday as Mount Sinabung spewed forth lava and drowned the sky with choking ash. As many as 14 lives have been lost so far and many are fearful that more casualties will follow. Around 5,000 locals have been evacuated.

This is the most recent in a spate of eruptions since the volcano awoke in 2010 after 400 years of dormancy. Scientists had neglected it because they had long assumed it was safe. Now, they say they ‘cannot predict’ when it might strike again. On the same evening on the other side of the world, panic spread as Ecuador’s Tungurahua roared to life. The recent frequency in volcanic activity across the globe is leading many experts to caution that worse will come.

Sinabung is connected to a fearsome family. It sits atop the lethal ‘Ring of Fire’, a 40,000km horseshoe of volcanoes which accounts for 80% of the planet’s eruptions. It includes Krakatoa, which devastated Indonesia in 1883, and the Toba supervolcano, which created a ten year global volcanic winter when it erupted 74,000 years ago.

Scientists disagree over what causes such eruptions but many believe they can profoundly alter the Earth’s climate. Storms of ash and sulphuric acid block out the sun, causing plummeting temperatures. Krakatoa’s eruption brought four years of exceptionally cold winters and fierce blizzards. They also wreak havoc on the ozone as CO₂ levels soar. Toba is thought to have accelerated the last glacial ice age, which resulted in 1,000 years of cooling.

Yet an increasingly prominent theory argues that the relationship is the other way round and climatic changes affect volcanic activity. Proponents see a clear connection between the weather-altering 41,000 year cycle of the Earth’s tilt and the timing of the grand eruptions that have shaken the planet. As the climate cools, the sea freezes into glaciers, which changes the pressure on the planet’s plates, allowing magma to squeeze its way to the surface.

Peak Panic

Some say this eruption is an isolated tragedy and we should not read too much into Sinabung’s recent outburst. A leading volcano expert has said ‘it’s almost at the end of its activity,’ and the dangerous lava dome that had started to form in November has now collapsed. The hysteria shows how quickly we start predicting Armageddon whenever something unexpected happens.

Others warn that these are signs of another supervolcanic eruption. Ten of the ring of fire’s major volcanoes have erupted in ten months. Sinabung is just 25 miles from Toba and it might waken the sleeping giant. In a volcanic winter, harvests would fail, and atmospheric changes would lead to tidal waves and cyclones hurtling across the surface of the Earth. We need to take note.

You Decide

  1. Is it worth worrying about natural disasters?
  2. Should people living in areas at risk from natural disasters be forced to relocate?


  1. Split into groups of four. You live near an active volcano. Discuss five ways you need to be prepared in case of an emergency. Report your findings to the class.
  2. Research and produce a short report on what you think are the top three global concerns for mankind.

Some People Say...

“Men argue. Nature acts.’Voltaire”

What do you think?

Q & A

There are no volcanoes in the UK, so I won’t be affected, right?
Wrong! A volcanic winter would not just affect the regions near the volcanoes, but the entire atmosphere of the Earth. There are also live volcanoes closer to home, such as Mount Etna in Sicily and Eyjafjallajökull in Iceland. When the latter erupted in 2010, it brought much of European air traffic to a standstill for weeks after.
So, is there any way to stop a volcano?
Not completely, but its damage can be ameliorated. In 1973, Icelandic citizens slowed flowing lava by pouring cold water onto it. On Mount Etna, engineers prevented lava flowing onto villages by using explosives to blast holes and create a channel.

Word Watch

Active volcanoes are those which have erupted in the last 10,000 years. Dormant volcanoes have not erupted in the last 10,000 years but are expected to erupt again in the future, whereas extinct volcanoes are expected never to erupt again. There are approximately 1,500 active volcanoes in the world and 75% of them are located on the Ring of Fire.
Glacial ice age
Often confused with an ice age, a glacial ice age is a colder phase within the longer period of an ice age. During the last of these, the whole of modern day Canada was covered in a sheet of ice, as well as much of the US and the British Isles.
Earth’s tilt
Every 41,000 years the Earth tilts 2.4 degrees then back again. Summers become much longer for one period, then winters longer for the next. Currently the Earth is halfway between the extremes of its tilt.


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