Hypercanes, supervolcanoes, and what Earth’s distant past can teach us about where we are now

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Artist depiction of the mass extinction at the end of the Permian Period. Image: Jose-Luis Olivares/MIT

HONOLULU (KHON) — Only five full months have gone by this year, and already it feels like an eternity separates the reality we live in now from the one we knew at the end of 2019.

You’d be forgiven for forgetting that 2020 started off with the assassination of a high-ranking Iranian general. A few weeks later Kobe Bryant died in a tragic helicopter crash alongside his daughter Gianna and 7 others. COVID-19 arrived in the islands mid-February and has remained a daily presence ever since, despite interruptions from presidential primaries, murder hornets and, more recently, nationwide protests.

On top of everything else, as of yesterday we are in hurricane season for the next six months, because apparently not enough has gone wrong this year. But if it seems like things can’t get any worse, just ask a geologist.

“There have been lots of crazy, chaotic events in Earth’s history that killed lots of species on the planet,” said award-winning science writer Peter Brannen, “but only 5 have been picked out that killed at least 75% of life on Earth.”

These five events are called mass extinctions, which Brannen detailed in his book The Ends of the World. Mass extinctions happened at the end of the Ordovician Period (445 million years ago); in the Late Devonian Period (374 and 359 million years ago); the End Permian Period (252 million years ago); the End Triassic Period (201 million years ago); and most infamously, at the End Cretaceous period (66 million years ago).

In the unfathomably long history of the planet, Earth has been a number of different worlds, many of which would seem like sci-fi nightmares to us — especially during mass extinction events.

“We think of Earth as having these guardrails that will always keep things Earth-like,” said Brannen. “But mass extinctions are times when Earth becomes un-Earthlike.”

Although the extinction of the dinosaurs gets most of the public’s attention, the planet has never been more ludicrously alien than it was during the end of the Permian Age. Referred to as “The Great Dying,” an estimated 96% of all life on Earth was extinguished in a Dantean congress of geological Grim Reapers. Brannen writes:

There was an ocean that was rapidly acidifying — one that, over huge swaths of the planet, was as hot as a Jacuzzi and completely bereft of oxygen. There were sickly tides suffused with so much carbon dioxide and hydrogen sulfide that either poison would have sufficed as a killer in its own right. There was a Russian landscape detonating and being smothered in lava several miles deep. There was a fog of neurotoxins and lethal smog streaming from these volcanoes and, high above, an ozone layer blasted apart by halocarbons, inviting a bath of lethal radiation at the planet’s surface. There was forest-destroying acid rain and a landscape so barren that rivers had stopped winding. There were carbon dioxide levels so high, and global warming so intense, that much of the earth had become too hot even for insects.

The Ends of the World

“Bad things happen all the time, but the worst things that have ever happened are a confluence of amazingly bad things happening at once,” Brannen said. “When you have a half billion years to play with, eventually you’ll have some really bad hands.”

Hypercanes and Supervolcanoes

Two phenomena from Earth’s worst hands felt particularly relevant to life in Hawaii: extreme hurricanes called hypercanes, and massive supervolcanic eruptions.

“Climate models on supercomputers show that if you make it hot enough, you have these unbelievably intense hurricanes of 500 mph winds — winds you’d only get from a nuclear bomb blast,” Brannen said.

Just how hot is “hypercane hot?”

Photo: MIT

“There’s a threshold where once you make the ocean warmer than 38 degrees celsius/100 degrees Fahrenheit — we’re talking hot tub temperatures — storms have this phase change where they go from hurricanes to hypercanes.”

Worse yet, it’s also believed that warming seas lead to slower atmospheric circulation in general. This suggests that the forward movement of hypercanes — how fast storms move across a surface area — could be slower, even if the windspeed is faster. This causes storms to linger for longer durations in the same places, pummeling landscapes into rubble. This dynamic has been observed in recent hurricanes.

Then there are supervolcanoes.

“People typically use the word ‘super eruption’ to refer to things like Yellowstone, which would be explosive and devastating to civilization. But they’re not that unusual in earth history. They go off pretty regularly and life doesn’t seem to mind much.

“Continental flood basalts are a totally different class of eruptions that put things like Yellowstone to shame. Where Yellowstone would cover a few states in a few inches of ash — totally disrupting agriculture and causing chaos — the largest continental flood basalts in Earth’s history, the one’s associated with mass extinctions, erupted with enough lava to cover the lower 48 United States over a kilometer deep.”

Photo: USGS

In Hawaii we’re intimately familiar with this, whether we know it or not. The Hawaiian islands were created by one of the most continually active basaltic volcanoes on Earth.

“Hawaii is made of basalt. It’s an ongoing hotspot that’s spewing basalt over millions of years. What happens in mass extinctions is, the eruptions happen under continental plates, under land that was already there. You can imagine it as all of Hawaii coming up at once in the middle of the continent. It’s not a mountain, it’s a whole area of a continent erupting continuously over hundreds of thousands of years in pulses.”

Fortunately, hypercanes only definitively exist on climate models — “I don’t think there’s any convincing physical evidence for apocalyptic hypercanes” — and while we know supervolcanic eruptions have occurred, they are exceedingly rare: “not once every few hundreds of thousands of years, but once every tens of millions of years,” said Brannen.

Lessons from the Dead

“Even things that happened a half billion years ago on an alien version of our planet tell us things today,” Brannen said.

Consider the hypercane:

“We’re not going to get to hypercanes any time soon but we will have to worry about more damaging hurricanes in the near future. The principal is the same: for every degree warmer we make the oceans, there will be more water vapor, more energy feeding into these storms, and then they become more powerful.”

Image: Stocktrek Images

Moreover, the dinosaur-destroying asteroid provided clues as to what really causes mass extinctions.

“In the last 30 years we’ve gone to older and bigger mass extinction events looking for asteroids and didn’t find any. Instead what we’ve found was climate change and carbon. It’s been a scary revelation,” Brannen continued. “The worst things that have happened in Earth’s history happened when lots of CO2 was in the air. In the past it came from volcanoes, but the planet doesn’t care if it’s volcanoes or power plants; it’s going to react the same way.”

Some previous mass extinctions were caused by the unfettered growth and preponderance of life itself — an eerie resemblance to the metastasis of the human species over the last 10,000 years.

“When plants and trees took over the planet, they disrupted the global geochemical cycle in ways that we’re also doing today. There was a lot of phosphorous in the Late Devonian that caused these huge algae blooms that robbed the seas of oxygen and killed sea life. We’re doing the same thing now when we mine phosphorous from rocks and it washes into seas.”

Photo: Albert J. Copley/Getty Images

There are other ways human activity is mimicking the otherwordly conditions the Earth has experienced during mass extinction events.

“During the first mass extinction you have an island world where life was stranded and couldn’t move. We’re reconstructing some of those conditions by breaking up habitats and not allowing animals to migrate. When climate changes in the next century — even if we do our best to mitigate it, it’s still going to change — we’re going to have to create space for animals to move around and migrate.”

This asks the question: are humans the next mass extinction event? So far the answer isn’t “no” so much as “not yet.”

“It’s hard to appreciate what that means to cause the destruction of a mass extinction,” said Brannen.
“Geology tells us how resilient life is. There have been 3 massive Yellowstone super eruptions in the last few million years. One would be devastating to things today, but geologically it’s just a hiccup. To cause a mass extinction, you have to be truly exceptional.”

Still, that’s not a get-out-of-apocalypse free card.

“Civilization pumping gigatons of carbon into the atmosphere is pretty exceptional. We’ve re-organized the biosphere in ways that are going to be visible on the fossil record for millions of years. Geology is very good at erasing stuff. We’re not going to leave much of a physical trace behind, but our legacy of extinctions and moving species around is what’s going to live on long after we’re gone.”

No matter how tortuously long this year has felt thus far, geologically speaking 2020 is indistinguishable from 2020 BC, during the middle of the Bronze Age. The history of humankind is a fraction of a fraction of the planet’s existence.

“We’re like an asteroid with a steering wheel,” said Brannen. “We don’t have to hit the planet, but there’s reason to be worried. Right now we’re the stewards of life on Earth. It would be incredibly tragic if we used this brief moment to trash the place. That’s the parting message.”

Trilobite fossils. Photo: Shutterstock

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