Our directory of things of interest

University Directory

Sulphur breath: tracking the emissions of volcanoes

The sulphur fumes of Mount Ijen in East Java, Indonesia The sulphur fumes of Mount Ijen in East Java, Indonesia Shutterstock
12 Apr
2017
In a new report, researchers have calculated the global emissions of sulphur dioxide caused by volcanic activity

Sulphur dioxide (SO2) is an aerosol that cools the atmosphere, can cause acid rain, and, at low altitudes, causes respiratory problems in humans. Volcanoes are natural sources of the gas and often we associate these emissions with dramatic eruptions. In reality, however, most of the gas is emitted when they are not erupting – through their everyday puffing and steaming.

‘Daily volcanic emissions are a constant input to the Earth’s atmosphere,’ says Simon Carn, lead author of a new report on global volcano emissions and associate professor at Michigan Tech in Houghton, Michigan. ‘These can impact climate in more subtle ways than a big eruption.’

Mount Erebus in AntarcticaMount Erebus in Antarctica was monitored from space for the first time (Image: Pagnanelli)

In order to get a good idea of how much SO2 is being regularly released, Carn and his team have used satellite data look at the respiration of 91 active volcanoes across the globe from 2005 to 2016.

They found that 20 to 25 million tons of SO2 are being emitted annually, considerably higher than a previous estimate of made in the 1990s of 13.4 million tons. However, Carn believes that this doesn’t mean that volcanoes are emitting more, only that measurements are becoming more accurate:

‘The satellite measurements we used cover the entire globe, and so we were able to measure emissions from many more volcanoes than any previous study.’

The global range of the satellite data also brought some surprises. Strong SO2 pulses were detected from volcanoes that had been completely off the radar to most volcanogists. ‘Many volcanoes were known to be strong emitters of gas,’ he says, ‘but a few in remote parts of countries like Indonesia and Tonga were new discoveries.’

newnewgifThe wax and wane of volcano emissions on the coast of Central America (Image: Carn et al)

While the collective SO2 has stayed the same, changes can be seen at an individual level. This is because emissions of SO2 are mainly related to the supply of fresh magma. ‘A volcano’s variable magma supply would cause its emissions to wax and wane over time,’ says Carn. ‘Meanwhile, volcanoes with a continuous supply of magma have roughly constant emissions.’ Because of the gas and magma relationship, changes in SO2 can also be used to forecast potential eruptions.

AsoMount Aso, Japan showed an increase in SO2 emissions before eruptions in 2014 and 2016 (Image: Shutterstock)

Human activity produces twice the amount of SO2 as volcano emissions, mostly by the burning of fossil fuels – particularly solid fuels such as coal. Over the past few decades, however, stricter policies and changes to industry have brought about a steady decline of human emissions of the gas. As this continues, volcano monitoring will continue to demonstrate the natural background levels of SO2.

Related items

NEVER MISS A STORY - Follow Geographical on Social

Want to stay up to date with breaking Geographical stories? Join the thousands following us on Twitter, Facebook and Instagram and stay informed about the world.

More articles in NATURE...

Oceans

Steps to regulate fisheries and protect marine reserves can be…

Wildlife

Government proposals to change conservation legislation could see vulnerable mammals…

Wildlife

New research confirms that sharks navigate using the Earth's magnetic…

Nature

The field of bioremediation involves cleaning up toxic waste products…

Wildlife

A new analysis tots up the cost of invasive species…

Climate

It’s surprisingly difficult to know why trees die, but understanding…

Nature

By the late 1980s, almost all mature specimens of the…

Oceans

Scientists are discovering that narwhal tusks reveal a great deal about…

Climate

Climate change is bringing earlier, dangerous 'false springs', longer summers…

Wildlife

A victory for conservation, South Africa has announced plans to…

Energy

The UK has made little progress decarbonising heating, but a significant source…

Nature

The concept of 'natural capital', where the value of nature…

Geophoto

Prestigious photography competition returns for a fourth year

Climate

Founded in the USA by Denis Hayes, Earth Day became…

Geophoto

Tom Goldner's project Do Brumbies Dream in Red? is an intimate portrayal…

Wildlife

Not your usual tune: translating spider's silk into sound could…

Oceans

Millions of oysters have been rescued from the struggling shellfish…

Climate

History is littered with examples of fungi helping to digest…