Huge volcanic eruptions for decades on end spurred a set of “mega El Niños” that played a big role in the Great Dying. Photo: Unsplash
Somewhere around 252 million years ago, there was a huge spike in global temperatures. That was the foundation for the largest mass extinction event in Earth’s history, resulting in the deaths of around 90 percent of all ocean species and 75 percent of those on land. According to a recently published study, a series of “mega El Niños” played a big part.
“[Researchers] found that a combination of extreme El Niño events and mean state warming led to deforestation, reef demise, and a plankton crisis, all of which resulted in a positive feedback cycle that led to an even warmer mean climate and still stronger El Niño events,” said Jesse Smith, an editor at Science.
Way back then, a few million years of huge volcanic eruptions in what we now call Siberia spewed piles and piles of gasses into the atmosphere. Much like we’re seeing today, those gasses drastically changed the planet’s climate and kicked off the El Niño events. The Earth was hammered by years of droughts, flooding, and wildfires which took their toll on pretty much every living thing. But the exact reasons behind the so-called “Great Dying” have been a little murky.
Researchers knew that there was that temperature spike. They knew it likely had something to do with the immense amount of volcanic activity. But what wasn’t all that clear was what kind of knock-on effects that activity had.
“[The findings] really build into an emerging picture that it’s a bit more nuanced of an extinction than we previously had appreciated,” said Erik Gulbranson, a sedimentary geochemist at Gustavus Adolphus College in Saint Peter, Minn., who was not involved with the new study.
The Great Dying has always been a mystery because it wasn’t the only point in time where there was global warming. But this particular period of time, which sat on the cusp of the Triassic, was far more deadly.
“We’ve got this intense global warming,” said paleontologist David Bond, “but we have other episodes of global warming in the geological record that don’t do anything nearly as bad to ecosystems as this.”
As you (hopefully) know by now, weather and climate are different things. The weather is what you see out your window right now. Climate refers to weather patterns averaged out over longterm periods. When someone holds up a snowball as an example of something that refutes the proven fact that on average, our planet is heating up, they’re either uninformed or willingly attempting to confuse the uninformed. Both weather and climate, however, are important for life.
“Species care about climate, but what they also really care about is weather,” said Alexander Farnsworth, a paleoclimate modeler at the University of Bristol in England. El Niño is an example of a “climate wobble,” wherein the weather changes for long periods of time in a relatively predictable manner. Today, an El Niño year means that much of North America will be hotter and drier, but also induces droughts and floods elsewhere.
Researchers studying the Great Dying looked into the Earth’s climate patterns from way back then. Using seawater temperatures — which are discerned using the amount of oxygen found in fossilized fish teeth, they were able to create simulations of what the Earth’s atmospheric and ocean circulation patterns might’ve looked like. This, according to Science News, allowed them to produced “a more cohesive picture of climate during the Great Dying.”
If the simulation is correct, much of the planet was seeing temperatures of upwards of 104°F for most of the year.
“When carbon dioxide levels initially doubled from about 410 to 860 parts per million and global temperatures rose,” Science News explained, “the El Niño–like warming spells originating mostly over the late Permian’s giant ocean, Panthalassia, grew more intense, the team found. (In comparison, current CO₂ levels are hovering around 422 ppm.) Over time, the swings lengthened too, sometimes stretching for nearly a decade.”
After a few decades of the “mega El Niños, forests would have withered up and died, which in turn would see less greenhouse gasses pulled from the air. As the volcanoes continued to erupt, the problem became a self-fulfilling prophecy and the world became uninhabitable for many creatures.
“You get more warming, more vegetation die-off, stronger El Niños, higher temperatures globally, higher weather extremes again, leading to more die-off,” Farnsworth explained.
With any luck, researchers are hoping that the information they’ve put together can help us solve or prepare for the rapidly approaching future.
