Large Igneous Provinces: The Volcanic Eruptions That Make Yellowstone Look Like A Hiccup

“The area well beyond Missoula, into Canada, and down into Colorado and Utah, would all see extremely devastating effects of ash fall,” Van Eaton explained, “to the point where it would be dark in the middle of the day.” 

Crops would fail; famine would be inevitable; even just breathing would be difficult. And “there’s rarely just a single event,” Van Eaton added. “Imagine dealing with the aftermath of this size eruption, and then having another one happen a couple weeks later.”

It would be nothing short of a nightmare scape. So when we tell you that there’s something out there that’s much, much more potentially destructive, you’ll understand just how bad things could get.

What are large igneous provinces?

Siberia, India, Southwest China, Ethiopia, and Yemen – dotted around the globe, there are areas that stand out, geologically speaking, from the rest of the world. Why? Because they’re large igneous provinces (LIPs): massive, sprawling regions of igneous rocks, formed tens or even hundreds of millions of years ago in volcanic eruptions so huge that they changed the face of the planet itself.

“You have the potential for truly enormous eruptions, possibly up to 10,000 cubic kilometers erupted in a single event,” Leif Karlstrom, an Earth scientist at the University of Oregon, told PBS. “And that will happen repeatedly over the course of a large igneous province event.”

“These lava flows blanket the earth, and they travel for hundreds of kilometers,” he explained. “The flow rate is so high that they are not cooling – [they’re] flooding the landscape, filling in topography, and forming a stack of basaltic rocks that can be kilometers thick.”

So, what would an LIP eruption look like? Well, think of the biggest volcanic eruption you know. Krakatoa, maybe, which, when it erupted in 1883, was responsible for more than 35,000 deaths and could be heard as far away as Australia; perhaps Mount Tambora, whose eruption in 1815 was the largest in recorded history, sending ash raining down over thousands of kilometers in every direction and producing the so-called “Year Without a Summer” in 1816. Anything like that will do.

Now scale that up by a factor of, oh, let’s say 10,000, and you have an idea of what a large igneous province event might look like. “A LIP is not a single dramatic event like Mount Pinatubo, or the explosive Mount Tambora eruption in 1815,” explained Stephen Grasby and David Bond, geologists at the Geological Survey of Canada and the University of Hull respectively, in a 2023 article for Elements magazine.

Instead, radiometric dating “indicates that LIPs extruded lava flows over tens if not hundreds of thousands of years,” the pair wrote. “As such, LIP events are better thought of as a long series of many thousands of seemingly mild Laki-like eruptions, rather than a single massive explosive eruption.”

“Mild” may be understating it. Laki, they acknowledge, is a volcanic fissure in Iceland which, when it erupted in 1783 and 1784, “decimated Iceland’s livestock and crops, leading to a famine that killed approximately a quarter of the island’s human population,” as well as “cool[ing] the Northern Hemisphere so much that crops failed and livestock across Europe was poisoned, leading to – according to some historians – the French Revolution.”

In other words: an LIP event is akin to some of the biggest, most impactful volcanic eruptions – but if they simply never stopped erupting.

And after a while, the world just can’t cope with such an onslaught.

Living through a LIP

Not all LIP events are deadly. As with volcanoes in general, most of them are underwater in any case, which highly reduces the impact they can have. Even on land, an LIP event that happened to occur in the right place, with the right rate of eruption and gas emissions, could still fall short of fully overwhelming the planet and its species.

That said, we’ve never directly seen one in action. So, let’s say an LIP starts waking up tomorrow. What should we expect?

Well, if it’s similar to the Siberian Traps LIP from 250 million years ago, we’re in trouble. This is the LIP that drove the “Great Dying” – the greatest mass extinction event in Earth’s history, which saw something like 90 percent of all species on Earth die off.

Death for these ancient animals came in the form of two million years of eruptions; four million cubic kilometers (960,000 cubic miles) of nickel-rich lava and gases being spewed out from the bowels of the Earth, burning the land and boiling the sea. The minerals released provided ample fuel for methanogens – microorganisms that generated huge amounts of methane gas, suffocating life in the oceans and trapping vast amounts of heat in the atmosphere. Virtually nothing survived.

It’s perhaps surprising, then, that – at least at first – the event may not have seemed all that dramatic. The amount of molten rock ejected over the period sounds like a lot – it’s about the same as all of the contiguous US minus California, Montana, and Michigan, filled to the depth of the CN Tower, if that helps at all – but averaged over two million years, it’s hardly anything: just 0.5 cubic kilometers per year, or to put it another way, less than two-thirds of the amount released in the 2018 Kīlauea eruption in Hawaii. 

But sheer volume really isn’t everything. The “constant and highly productive magmatism” assumed by taking a raw mean of volume over time is “an unlikely modern eruption scenario,” pointed out Grasby and Bond. “Instead, LIP eruptions are a stochastic process, with lava extrusion occurring as a series of sequential eruptions that can be modeled as a multifractal time series.”

In other words, every little individual eruption and explosion builds on its predecessor, resulting in an unpredictable chain of endless reactions. Eventually, too many tipping points are reached, and then, perhaps very suddenly, it’s the end of the world. 

“Some individual eruptions may not be significant on their own,” explained Grasby and Bond, “but at high enough frequency, they could build atmospheric contaminants at rates faster than they are removed, generating increasing stress on biological systems.” 

“This itself could be enough to drive a mass extinction,” they wrote, “or it could weaken the normal buffering capacity of organisms, making ecosystems more vulnerable to rarer, more extreme eruptions.”

Whether destructive enough to kill off masses of life on their own, or just to kick off a series of events that leads to the same outcome, the conclusion is clear: large igneous provinces are bad news. And the record bears that out to a spooky degree: “Several decades of research effort have generated sufficient evidence for a close temporal link between LIP events and multiple mass extinctions,” noted Grasby and Bond. 

“While this does not prove causation,” they admit, “the frequency of the link suggests that it is more than a coincidence.”

No need for the LIP

Theoretically, there’s no real reason an LIP event couldn’t happen today. It is, however, unlikely. 

While it’s an open question as to whether LIP events turn up with any kind of pattern, there is, on average, something like 10 million years between each one – giving us around 3 million years of breathing room until the next one is “due”. 

Besides, we’d have a few warning signs. Even just at Yellowstone, “prior to any eruption […] we would be seeing really dramatic changes,” pointed out Michael Poland, Scientist-in-Charge at the Yellowstone Volcano Observatory, for PBS. “We would see huge numbers of earthquakes; the ground would be swelling possibly by many, many feet; there’d be parkwide changes in […] the amount of heat that was coming out of the ground; changes in the amount and the composition of the gases were coming out.”

So, we don’t need to worry unduly about LIP events – but the truth is, there’s a much more concerning lesson we can draw from LIPs and mass extinctions.

Around 55 million years ago, an LIP event caused what’s now known as the Paleocene-Eocene Thermal Maximum (PETM). It triggered a rapid emission of greenhouse gases, particularly carbon dioxide, and the planet’s climate swung wildly: temperatures rose by 4-6 °C (7.2-10.8 °F) worldwide, and rainfall increased dramatically, transforming the planet into essentially one giant rainforest.

Meanwhile, the oceans became all but dead. Sea levels rose dramatically; circulation patterns were disrupted; the water lost oxygen and became acidic. Entire ecosystems collapsed; among those who survived, major changes in their bodies were needed to cope with the global soaring temperatures.

But here’s the thing: the volume of CO₂ being released during that time was far, far less than the amount we’re emitting right now.

“The PETM […] is thought to be the best ancient analog for future climate change caused by fossil fuel burning,” said Lee Kump, professor of geosciences at Penn State, back in 2011. He had just helped lead a study investigating just how long the carbon release took during this cataclysmic period of Earth’s history, finding that the whole thing lasted around 20,000 years.

But “rather than the 20,000 years of the PETM which is long enough for ecological systems to adapt, carbon is now being released into the atmosphere at a rate 10 times faster,” said Kump. “It is possible that this is faster than ecosystems can adapt.”

The upshot is that, as devastating as the PETM was, we don’t need an LIP event for it to reoccur. In fact, we don’t need to do anything at all – because, unless we drastically change how much carbon we pump out into the atmosphere, it looks like we’ll equal the levels seen during the PETM in less than 150 years.

After that? Who knows what will happen. The world will probably recover – after all, it’s still here and thriving long after the PETM – but it won’t be quick, and it won’t be easy.

“If we combust all known fossil fuel reserves, that’s about 4,500 billion tons of carbon,” pointed out James Zachos, professor of Earth sciences at the University of California, Santa Cruz, back in 2005. “The recovery time for a comparable release of carbon [during the PETM] was about 100,000 years.”

“Even after humans stop burning fossil fuels, the impacts will be long-lasting,” he said.