Long ago, carbon was a stone buried in the ground as securely as a secret. Then an ecological catastrophe of unprecedented proportions began. The stones burned, and the atoms inside them decayed into carbon dioxide and other greenhouse gases.
Temperatures have risen, and wildfires – always a natural part of the ecosystem – have become more frequent and violent. The forests vanished into flames. The carbon once stored in countless leaves was blasted back into the atmosphere, which got hotter and drier, and fires flared even faster.
Without trees to hold them back, nutrients leached from the bare soil into lakes and streams. These nutrients fed the algae, which bloomed in poisonous amounts while other species starved.
By the time it ended, most of the living things on Earth—up to 95% of the species in the ocean and more than 70% on land—were dead.
New research suggests that the accelerating fires of this apocalyptic period 252 million years ago were not just a symptom of a warming planet, but were themselves the driving force behind the extinction. Increasingly frequent fires overwhelmed the ability of plants to adapt and set off chains of events that threatened life in habitats untouched by flames, as did the scientists. afraid of what they do today.
These events took place in an event known as end of the Permian extinction, or the Great Death. Over tens of thousands of years, between the birth of the supercontinent Pangea in the Permian and the appearance of the first dinosaurs in the Triassic, a series of interconnected climate disasters wiped out much of the planet’s life.
Although millions of years separate the events of the Great Dying from the wildfires that threaten the forests of the modern world, the new study highlights eerie parallels between that ancient period of global warming and our own.
“There is a kind of interaction between the present and the past,” he said. Chris Mayspaleontologist at University College Cork in Ireland and lead author of a study published last week in the journal PALAOIS.
Today’s vicious cycle of warmer temperatures, less rainfall and more fires repeats the sequence of climate shifts that wiped out life at the end of the Permian, Mays said.
While these long-standing disasters have likely been in place for thousands of years, the harsh end result offers a sobering warning about what uncontrolled warming looks like.
“We are warming the world on a scale of hundreds of years, and there is a good chance that with the temperature rising and the environment changing at such a rapid rate, ecosystems will collapse,” Mays said. “The pace of change is actually very important. And this is where we actually see a rather disturbing picture today.”
Frequent forest fires caused by lightning and other natural events were a normal part of life during the Permian era, long before species began to die out en masse. During their research in eastern Australia and Antarctica, Mays and his co-authors at the Swedish Museum of Natural History found shiny black shards of petrified charcoal among fossilized plants from that era, a sign of a prehistoric wildfire. The fossil record has shown that, just like today, plants in fire-prone areas have evolved adaptations to protect themselves from fire and regenerate more quickly after an accidental fire.
The situation changed after the start of a massive volcanic eruption on the territory of modern Siberia in Russia. Lava and greenhouse gases have been erupting from the volcano for about 2 million years, which is less like Vesuvius and more like Hawaii Volcanoes National Park.
Huge volumes of greenhouse gases emitted during this time have catastrophically heated the Earth. The average global temperature is likely to have risen 6 to 12 degrees Celsius (about 11 to 22 degrees Fahrenheit) at the Earth’s equator and 10 to 14 degrees Celsius (18 to 25 degrees Fahrenheit) at the poles. (For reference, climate scientists have warned that a 2-degree Celsius rise in global mean temperatures today could kill 99% of the planet’s coral reefs and endanger the collapse of the polar ice sheets.)
In this hotter, drier climate, the frequency of fires grew faster than the plants could adapt. They could no longer sustain the forests, and the most important source of carbon storage disappeared.
“Severe climate change and peak fire activity during the extinction seem to have pushed even these fire-adapted plants to a tipping point from which the entire ecosystem could not recover for millions of years,” Mays and co-author Stephen McLaughlin. wrote.
Understanding the largest extinction that took place on this planet provides valuable information about later environmental disasters. Mays’ team found that even forests acclimated to fire eventually gave way to hotter, drier climates.
“Even ecosystems that are in more protected areas – wetter areas, coastal areas that this article is about – even those ecosystems are under stress from rising temperatures and a drier environment,” he said. Regan Dunn, a paleobotanist not involved in the new study. “Then one spark can really change the ecosystem.”
Dunn explores the important role of wildfires in the quarterly extinction approximately 15,000 years ago. This climate change (and the emergence of humans as predators) ended the reign of the saber-toothed cat, the American camel, the mastodon, and other species later discovered in the La Brea Tar quarries, where Dunn is assistant curator.
Life recovered after the Great Dying, of course. A study of fossils in southern China has shown that marine species capable of burrowing into the seafloor were among the first to recover from the long silence at the end of the Permian extinction. BUT paper Published last week in the journal Science Advances, adds to the evidence that animals that can escape underground are best equipped to survive the chaos.
“By studying the Great Dying, we find that it has affected everything, as you can imagine,” said David Botger, a USC paleoecologist who has worked on seafloor research. “Of course we see him recovering. But this recovery takes a long time, like a million years or more.”
The anthropogenic warming that the Earth will face in the foreseeable future is not yet as extreme as the temperature fluctuations of the Permian period. But these anthropogenic changes are occurring faster than those caused by nature alone.
“Nature has already done the experiment,” Botger said. “It’s not a pretty sight.”