Michael Kile

In an age of increasing hyperbole about natural phenomena it had to appear sooner or later: an alarmist claim that “climate change” (CC) was, could, can or is causing more intense volcanic activity on planet Earth.

So it was no surprise that a BBC WS CrowdScience team – presenter Caroline Steel, producer Emily Bird and editor Cathy Edwards – attempted last month to answer this question: “Could climate change lead to more volcanic eruptions? How will a heating planet affect volcanic activity?”

We spend a lot of our time thinking about climate change, but listener Paul [from near Blackpool, United Kingdom] has a question that isn’t usually part of the conversation. He wants to know whether a hotter atmosphere will affect how often volcanoes erupt, or make them more explosive when they do. (CrowdScience audio, 3 min.)

They were probably inspired by this article: Climate change could be triggering more earthquakes and volcanic eruptions. Here’s how.  It was posted on the World Economic Forum website on 14 August last year, “in collaboration with The Conversation”. The author, Matthew Blackett, a Reader in Physical Geography and Natural Hazards at Coventry University, suggested that:

• Climate change could cause more earthquakes and volcanic eruptions by increasing the weight of water on the Earth’s crust.
• When glaciers melt, the water can seep into cracks in the Earth’s crust, causing them to widen and weaken.
• This can lead to earthquakes, especially in areas that are already seismically active.
• Climate change can also cause more volcanic eruptions by increasing the amount of magma in the Earth’s mantle.

Consider, for example, his fourth claim. The only evidence given for it is a GSA research article published on November 16, 2017. Yet the summary stresses the uncertainties:

Over glacial-interglacial time scales changes in surface loading exerted by large variations in glacier size affect the rates of volcanic activity. Numerical models suggest that smaller changes in ice volume over shorter time scales may also influence rates of mantle melt generation. However, this effect has not been verified in the geological record. Furthermore, the time lag between climatic forcing and a resultant change in the frequency of volcanic eruptions is unknown.

Its ten authors claim their modelling reveals “an apparent time lag of about 600 years” between a past climate event and a “change in eruption frequency” in Iceland. Hence any “increase in volcanic eruptions due to ongoing deglaciation since the end of the Little Ice Age may not become apparent for hundreds of years.”

We shall have to wait a while, dear reader, before we know whether this hypothesis is more than model-driven academic speculation. How jolly convenient.

Whatever the case, CrowdScience went off to New Zealand to find an answer to listener Paul’s question, and to check out traditional Maori knowledge about volcanoes.

Presenter Caroline Steel had a chat with two volcanologists, Geoff Kilgour from Geological and Nuclear Sciences (GNS), Taupo, New Zealand; Heather Handley, Associate Professor of volcanic hazards and geoscience communication with the University of Twente, The Netherlands; and  Pouroto Ngaropo, historian and Matauranga Māori expert in Rotorua, New Zealand.  (A 27 minute podcast is available at CrowdScience.)

Once again there was more speculation than fact, more sizzle than sausage.

 Dr Kilgour speculated that CC could affect ash distribution after an eruption by causing a “slight change in wind patterns”. His conclusion: “We need to do a lot more work to understand the impacts of CC on volcanic behaviour.” (Audio: 11.0min.)

Dr Handley was more emphatic. She referred to the 2021 Mount Semeru eruption in East Java. She suggested it began after several days of heavy rain from December 4^thcaused the collapse of its lava dome. Yet major eruptions occur here so frequently it is hard to accept bad weather is a significant causal factor, at least for me.

Ms Steel: It’s kind of mind-blowing that heavy rain could cause a series of volcanic eruptions. In my head volcanoes are so strong and steady that the fact they can be affected by rain, or even CC, just feels really surprising.

Dr Handley: It’s definitely an area where we’re starting to think along these lines. What are the other externals – factors outside normal volcanic behaviour – that can influence volcanoes?

Ms Steel: What about the melting glaciers you mentioned earlier, whose effects we might only start seeing at some time in the future? What time scales are we talking about there?

Dr Handley: So far they think it’s about 1,000 years. But being prepared for events in the future that might happen on longer time scales are something we should still be understanding and preparing for. It’s not today, but future generations have to be prepared to deal with it. And so I think it’s very important as a scientist to have a more holistic view of a system to better understand what the impacts and implications might be of change. (Audio: 19.0min.)

Pouroto Ngaropo quoted a Maori prayer. It was, he said, all about connecting people to the land and to the “geothermal energy that bubbles beneath their feet.” This ancient energy enables me to connect to the beginning of time, and to the Creator.” From a Maori perspective, mountains are a living and breathing entities. “We have a saying: ‘I am the mountain and the mountain is me’. As for Maori knowledge, it is “similar to scientific knowledge.”

Ms Steel: Pouroto works closely with geologist Geoff and his colleagues at the GNS. They share their knowledge so they can better understand the changing landscape. Knowledge of the land has been passed down through generations, an aural record of how volcanoes have behaved in the past, how they have been affected by changing seasons and weather patterns, which is a key part of understanding how they might respond to a warming planet in the future. (Audio: 22min.)

Pouroto: Our ancestors were a lot more attune to the natural world around them. When you are living deep within the heart of your natural environment you can sense and feel things.

Ms Steel: This wisdom, passed down in song through the ages is culturally and scientifically invaluable; and by combining deep knowledge with cutting-edge scientific research, Pouroto and Geoff are learning even more about the land, with the aim of forecasting eruptions and saving lives. (Audio: 25min.)

Addressing listener Paul, however, Ms Steel admitted defeat. She ended the episode with this comment:

Ms Steel: When it comes to volcanic activity, it’s not so much the warming Earth we need to worry about, but the melting glaciers, changing winds and extreme weather events. This probably sounds all too familiar. Geoff, Heather and Pouroto are doing their best to build a clearer picture, but the impacts of man-made climate change on the planet – volcanoes included – are very unpredictable. (Audio: 27min.)

Just as well too. For some reason the CrowdScience episode did not mention the elephant, if not in the room, then in the Bay of Plenty. Neither Maori traditional knowledge – nor scientific knowledge from real-time monitoring by New Zealand’s GNS Science – predicted or prevented this tragedy: the explosive eruption of the active Whakaari / White Island volcano on December 9, 2019. Perhaps it did not fit the program’s CC narrative.

It is difficult today to comprehend how NZ agencies allowed its most active volcano to be promoted as a tourist destination, especially after a similar eruption there in 2016, fortunately at night.

There were 47 people on Whakaari at the time of the 2019 eruption: 42 paying tourists and five tour guides employed by commercial tour operators. They were all on the crater floor, at different locations along a circular route used by the operator. (Photo: webcam image below).

Anyone caught in a pyroclastic density current (fast-moving cloud of hot ash), is in deep trouble. Twenty-two people died, either in the explosion or from injuries. Twenty-five were injured, most needing intensive care for severe burns. Two bodies were never found. Recovery efforts were delayed due to seismic and volcanic activity, heavy rain and the presence of toxic gases.

A webcam image showing hikers walking inside the crater of the Whakaari/White Island volcano, a minute before the 9 December, 2019 Whakaari/White Island eruption. Source: GNS Science (formerly the Institute of Geological and Nuclear Sciences)

WorkSafe NZ later investigated the tragedy. It charged 13 defendants under s 37 of the Health and Safety at Work Act 2015. Six pleaded guilty and six had their charges dismissed either prior to or during a criminal trial in the District  Court, Auckland. The remaining defendant Whakaari Management Limited (WML) was convicted on October 31, 2023.

One of the defendants was the NZ Crown Research Institute, GNS Science. It pleaded guilty to an amended charge in May 2023. GNS had been contracting Whakaari tour helicopter companies to fly its scientists to the island. GNS was sentenced by WorkSafe NZ for its failure to consult pilots about the risks of what they were doing between 2016 and 2019.

The most revealing expert witness was GNS Science principal scientist, Dr Gillian Jolly, also Chief Science Advisor for the NZ Ministry of Business, Innovation and Employment.

Dr Jolly told the courtroom on July 19 last year that Whakaari / White Island was showing signs of higher activity in the days before the disaster, but “volcanoes are inherently unpredictable”.

“We can never definitely say when an eruption might happen,” she said. “We never talk about volcanic activity being predictable. Prediction implies you know what is going to happen and when. We prefer to talk about forecasting and probability.” There was no mention of CC as a causal factor.

GNS Science had been monitoring Whakaari closely, Dr Jolly told prosecutor Kristy McDonald KC. GNS experts had visited the island five days before the eruption.

Whakaari, being a frequently active volcano, we used the full suite of monitoring [equipment]. On the island, we had two seismometers permanently providing real-time data, we had two global position system instruments, we had two differential optical absorption spectrometers looking at the gas coming out [of the volcano], and we had three cameras pointing at the active vent. (Dr Gillian Jolly, principal scientist, GNS.)

Whakaari was showing “heightened activity” just before the eruption. “For the period towards the end of 2019, we saw a number of parameters that were showing elevated signs. The more unrest indicators, the more likely an eruption.”

However, GNS could not use that data to determine when, or if, an eruption would occur: “Monitoring and forecasting volcanoes is like forecasting weather [or climate change], except you’ve got your eyes closed.”

It would have been impossible for GNS Science to provide an accurate warning with its current technology and understanding of volcanic activity. Even if it could, GNS had “no power” to stop tours from going ahead: “We’re not a regulator.”

A week before the tragedy, the GNS volcanic alert bulletin reported that volcanic unrest continued with “substantial gas, steam and mud bursts” at the vent at the back of the crater. The bulletin stated there was no direct hazard to visitors, but warned that eruptions could occur without warning.

GNS staff were advised to stay further than 520 metres from the vent. Dr Jolly said its experts considered the island “may be entering a period when eruptive activity is more likely than normal”.

According to Amy Williams, a RNZ reporter, the court was shown a draft volcanic alert bulletin, prepared on the day of the eruption, but not sent to tour operators.

GNS had kept the alert level at two – meaning there was moderate to heightened volcanic unrest. The bulletin described how Whakaari was “throwing mud and debris 20 to 30 metres into the air above the vent”.

“Overall this level of activity remains within the range of expected from moderate to heightened volcanic unrest,” the draft alert stated. “The current level of activity does not pose a clear hazard to island visitors.”

GNS estimated the chance of an eruption outside of the Whakaari crater rim in the next 28 days was one in seven.

A year later, Pouroto Ngaropo was interviewed by SBS Dateline. ’I still ask myself’, he said, ‘why did Whakaari take life? It was like the heart was ripped out of us all.”

I was on Whakaari the week before it exploded. I felt like something was not normal and I could already feel her crying with pain.

There was going to be a risk taking people to the island. As humans we always think we have control but we don’t: we are subservient to Whakaari because she can blow at any time.

Was it a message to us, to address our continual abuse of the Earth? I believe it was a reminder of how we need to look after the environment and look after one another.

Michael Kile

This essay was posted in Australia at Quadrant Online on April 13, 2024, with the title: “Volcanoes – The Climateers’ Latest Silly Scare Story.”