The world’s oldest evidence of wildfires can be found in a laboratory on the fourth floor of a brick building in Waterville, Maine. To the untrained eye, it looks like a black speck of fuzz, not much larger than the tip of a pin.For Colby College paleobotanist Ian J. Glasspool, it’s a Charcoal from 430 million years ago.
The specimen, which Dr Glasspool discovered in mudstone in south Wales, is one of many ancient charcoals studied in recent years to explore how fire burned in the past. Together, these remains help scientists understand how environmental changes over geological time have shaped and affected fires.
“They look boring,” Dr. Glasspool said, holding up the specimen embedded in a small resin dish. “But you can get a whole lot out of it.”
Dr. Glasspool said these ancient insights may not help us manage individual wildfires today. But they could provide a clearer understanding of the global fire phenomenon and how it affects Earth’s climate. This, in turn, could help modelers make more accurate predictions of future climate.
“The geological record shows that it’s more complex than ‘the weather gets hotter and there are going to be more fires,'” said Jennifer M. Galloway, a paleoecologist with the Geological Survey of Canada.Dr. Galloway recently published a paper in the journal Evolving Earth exist The merits of studying ancient wildfires as a way to understand today’s climate dynamics.
Fire is a fairly new phenomenon in Earth’s 4.54 billion year history. More than 90 percent of the time, Earth’s atmosphere and continents lack the oxygen and kindling needed to sustain a fire. A lightning strike may scorch the microbial mat here and there, but the burn is short-lived; the smoke and embers are all but gone. Sustained burning – and ultimately the geological record of fire – was not possible until plants appeared on land about 458 million years ago.
The earliest fires burned not forests, which would take millions of years to evolve, but simple plants like moss and liverworts. “We’re talking about things that by and large you could walk over and they wouldn’t even get your boots wet,” Dr. Glasspool said. At this time, a group of mysterious large plants called nematodes also dotted the landscape, and these may have also fueled the earliest flames, he added.
To study the remnants of these ancient fires, Dr. Glasspool first dissolved his rock samples in acid and then sifted out the tiny black specks that were left behind. To manipulate and position each spot for analysis, he used a wooden skewer with a whisker from his cat Bingo taped to the end.
“Low budget, do it yourself,” he said in the lab in February. If he used a store-bought paintbrush, his tiny swatches might get tangled in hair; Bingo’s beard gave him more control.
Examined with a simple light microscope, the charcoals revealed marble-like cell walls that had been originally preserved through the charring process. This process burns away all volatile organic matter, leaving only inert carbon that can remain unchanged for hundreds of millions of years.
Charcoal has a unique filamentous luster that helps distinguish it from coal (another form of carbon), which looks more matte under a microscope.
By tracking the abundance of charcoal at different intervals in the rock record, Dr Glasspool and his colleagues identified fire patterns that have emerged during past periods of global warming. He and his team found that charcoal content increased fivefold in 200-million-year-old sedimentary rocks collected in East Greenland. This period marked the end of the Triassic, when intense volcanic activity increased global temperatures by about 6 degrees Celsius and led to one of the worst mass extinctions in Earth’s history.
In 2010, Dr. Glasspool’s team reported that rising atmospheric temperatures Potential for increased wildfire activity In many ways. For example, warmth may produce thunderstorms and more frequent lightning strikes, a leading cause of wildfires throughout the ages.only Warming up by 1 degree Celsius According to a study by Imperial College London, it can increase the occurrence of lightning by about 40%. Dr Glasspool said this may partly explain why wildfires were so common at the end of the Triassic.
The fossil record also shows that as temperatures warmed, plants with small, narrow leaves became more common, while species with wider leaves largely disappeared from the landscape. This is likely a response to warmth, as smaller leaves dissipate heat more easily than larger leaves, his team reports.
Small-leafed plants create more intense fires, just like torn pieces of paper burn faster than intact pieces. “They dry faster and are more flammable,” Dr. Glasspool said.
More combustible vegetation, more smoke and more carbon dioxide in the atmosphere would further warm the planet, perhaps triggering more fires, more vegetation changes and more intense thunderstorms – a positive feedback loop , not much different from what it seems. Go out to play today.
The rock record gives us an idea of how long it might take for an ecosystem to recover after such a disturbance. Sediments left behind by the End-Permian mass extinction—a period of warming about 252 million years ago that marked the greatest loss of life in Earth’s history—suggest that charred wetlands took hundreds of years to dry out and burn. It will take thousands of years to recover.
“Hopefully we won’t have something like this happen again,” said Chris Mays, a paleontologist at University College Cork in Ireland. Research on these deposits 2022.
Modern global temperatures have increased much less than then—just 1.1 degrees Celsius since 1880, compared with about 10 degrees Celsius in the tens of thousands of years during the end-Permian extinction. But the pace of change today far exceeds that of the past. This rapid warming has already made wetlands more susceptible to fires: 42 million acres of tropical wetlands in the Pantanal region of South America are already burning. Seasonal burn rate is alarming. Sediments from the end of the Permian provide a sobering idea of what may happen if climate change continues unabated.
“There’s a lot we can do to prevent it from getting that bad,” Dr. Mays said. “But we’re looking at it as the absolute worst-case scenario.”
Sean Parks, a research ecologist with the U.S. Forest Service at the Rocky Mountain Research Station in Missoula, Montana, noted that the scope and severity of such fires are also a result of human behavior and land-use practices, not just climate. The result of change.
Still, Dr Parks said studies of the geological record and ancient climate patterns could help improve global climate models and inform land management decisions: “It’s interesting and excellent background information.”
Fernanda Santos, a scientist at Oak Ridge National Laboratory in Tennessee who studies modern fires in Alaska and works closely with climate modelers, agrees.
“I really value ancient data because they can give us new perspectives and new baselines,” Dr. Santos said.
