The dramatic eruptions of southern Pacific volcano Hunga Tonga–Hunga Haʻapai in mid-January reminded us that the Earth is a very dynamic place, where sudden events can create incredibly hostile environments and major damage.
While this event took many people by surprise, the volcano has been sporadically active since 2009, when eruptions first created a small island as the volcanic cone emerged from the sea. Satellite imagery has traced Hunga Tonga–Hunga Haʻapai’s history since then, but most of us paid little attention until late December, when explosive volcanic events known as Surtseyan eruptions blew volcanic ash and gases into the atmosphere and began to reshape the island. On Jan. 15, massive explosions generated huge ash plumes, atmospheric shock waves, and small tsunamis that crossed the Pacific Ocean.
This was all very impressive, but it was quickly apparent that Hunga Tonga–Hunga Haʻapai’s eruption was not all that large compared to many other events that have occurred during human history. In his excellent book Krakatoa, Simon Winchester traced the history of this massive Indonesian volcano dating back to an enormous eruption about 60,000 years ago. It is thought that there were three major eruptions since then, culminating in the well-documented event of Aug. 27, 1883 – “The Day the World Exploded”. Winchester tells us:
“… the eruption changed the world in more ways than could possibly be imagined. Dust swirled round the planet for years, causing temperatures to plummet and sunsets to turn vivid with lurid and unsettling displays of light. The effects of the immense waves were felt as far away as France. Barometers in Bogota and Washington, D.C., went haywire. Bodies were washed up in Zanzibar. The sound of the island’s destruction was heard in Australia and India, and on islands thousands of miles away.”
While nobody alive today remembers that Krakatoa eruption, many of us remember more recent, if less spectacular, events. The island of Surtsey emerged from the sea off southern Iceland in 1963 in a series of eruptions like those at Hunga Tonga–Hunga Haʻapai. In 2010, eruptions at Eyjafjallajökull in Iceland sent a massive plume of volcanic ash into the atmosphere, disrupting European air travel for more than a month.
Closer to home, the spectacular 1980 eruption of Mount St. Helens in the state of Washington rocked the northwestern United States and adjacent Canada. It literally blew the top off the mountain. As a graduate student, I had the opportunity to visit the site only a year later, and the devastation was incredible – whole forests simply blown down, roads buried and bridges washed downstream as rivers were choked by massive sediment flows.
As spectacular as these events are, most of the effects are confined in time and space to regions nearby, during and for years after the eruption. But clouds of volcanic ash can cause far more widespread and profound global events. Geologists can trace the eruption of Mount Mazama, which formed Crater Lake in Oregon about 7,600 years ago, by mapping the Mazama ash bed across much of northern North America, as far northeast as Greenland. Anthropologists believe that indigenous peoples of the Cypress Hills area in southeastern Alberta were driven away for up to 200 years by choking ash that killed vegetation and clogged rivers and streams.
Perhaps more important, volcanic ash and associated sulfur-rich aerosols blown high into the stratosphere can reflect sunlight and affect cloud formation, causing global cooling for up to several years – sometimes termed a “volcanic winter”. Mount Tambora in Indonesia erupted in 1815, resulting in global cooling and worldwide harvest failures in the “Year Without a Summer” in 1816.
So what does all of this have to do with future energy production?
To minimize humanity’s influence on the climate, we are planning to rely more and more on alternative energy sources that do not produce greenhouse gas emissions – particularly solar and wind power. The disappointing performance of wind power in Europe in 2021 highlights that when we generate electricity from sources that we don’t control, we are at the mercy of unplanned and untimely power shortages (Analysis: Weak winds worsened Europe’s power crunch; utilities need better storage). While we can look back at wind speeds in 2021 and interpret why they were relatively low, we cannot predict when that will happen again. Energy planners are now rethinking long-term power generation and storage plans with the realization that we cannot always count on the wind to be blowing as much as we would like.
We might think that we do not have to worry about such untimely fluctuations in solar energy. But perhaps we should. The eruptions of Tambora, Krakatoa, Mount St. Helens, and Mount Pinatubo in the Philippines (1991) all produced globe-spanning aerosols that produced measurable cooling and reduction of sunlight to Earth’s surface. I haven’t seen anybody speculate on how much effect such an event would have on modern solar power generation, but the reduction would be global, not confined to a single region. A large event on the scale of the Mount Mazama eruption would definitely cause profound reductions in solar energy over larger regions for longer periods of time. With less solar energy reaching the ground, would we see a concomitant reduction in winds?
So, what can we do? We can’t stop volcanos from erupting. But we can think about their potential influence on solar power generation when we are planning future energy systems. Some people, including Mark Jacobson of Stanford University, propose that humanity can meet all its future energy needs using only wind, water, and solar power (100% Clean, Renewable Energy and Storage for Everything). If we decide to go that route, what will happen if a massive volcanic eruption causes one of the global linchpins of energy to suddenly and unpredictably underperform for a year or more – particularly while causing crop failures and other disasters at the same time?
It is not highly likely that we’ll see a major volcanic event or something even more rare that would reduce solar input, such as an asteroid strike, any time soon. But it is inevitable on the scale of hundreds of years before humanity harnesses antimatter with dilithium crystals, or creates some other miraculous energy source. Perhaps we should take this line of thought as one more good reason to develop a diverse and robust set of energy sources and storage mechanisms during the 21st century energy transition.
In fact, we can take this thinking a step further. Just as human diversity contributes to the fabric and quality of our civilization, diversity of energy sources – not only wind, solar, and water, but nuclear, fossil fuels, and geothermal – can provide us with more robust energy systems and greater resilience in forging a bright future.