Wildfires
The new fire regime of the Anthropocene
Description
On 7 February 2009, the air over Melbourne reached 46.4 degrees Celsius, the hottest temperature ever recorded in that part of Australia. Across Victoria, fires that had been smouldering since the previous week exploded into something different. By the end of what came to be called Black Saturday, 173 people had died, mostly in their homes or trying to flee. Some fires moved at speeds previously thought impossible fronts of flame travelling at 70 kilometres per hour, generating their own weather, throwing burning embers kilometres ahead of the main fire. The Royal Commission spent two years documenting what had happened.
Black Saturday was treated as a once-in-a-generation event. It was not. The 2018 Camp Fire in California killed 85 people and incinerated the town of Paradise in less than a day. The 2019-2020 Australian Black Summer burned an area larger than England. The 2023 Canadian wildfires emitted more carbon than the country's entire fossil fuel economy that year. The 2025 Los Angeles fires destroyed entire neighbourhoods. Together, these events form a pattern that an American fire historian named Stephen Pyne has called the Pyrocene — an age of fire as defining for the present as the Pleistocene was for the deep past.
Wildfires have always been part of forested ecosystems, and many forests evolved to depend on periodic burning. The fires of the last fifteen years are different in character — larger, hotter, more destructive of human settlements, and increasingly capable of behaviours that defy the experience of professional firefighters. The reasons interact: a warming climate, a century of fire suppression that built up unburned fuel, the spread of housing into fire-prone landscapes, and the loss of indigenous burning practices that maintained those landscapes for thousands of years.
The question we're asking: what has changed about how forests burn, and how do we read the disasters of the last fifteen years against the longer history of fire?
What we'll see: the Pyrocene framing, the four big fires, what fire suppression did, and what indigenous practice knew.
Table of contents
01Pyne's Pyrocene
Stephen Pyne is a fire historian who spent fifteen seasons on the North Rim of the Grand Canyon as a wildland firefighter before turning to scholarship. His books have traced the relationship between humans and fire across continents and centuries. The argument he has been developing since 2015 is that the planet has entered a new fire age comparable in significance to the ice ages. The Pleistocene was defined by oscillating glaciers; the Pyrocene, in his framing, is defined by humans burning fossil fuels and reshaping landscapes in ways that have remade fire's relationship with the rest of the biosphere.
Pyne's framing is not metaphorical. Burning fossil fuels has produced the climate change making fires worse. Forests dried by heat waves carry more flammable fuel. Atmospheric warming generates fire-weather conditions. The fires release carbon that further warms the atmosphere. The 2023 Canadian wildfires alone emitted roughly 1.5 billion tons of CO2, comparable to the annual emissions of a major industrial economy.
02Four fires
Black Saturday in 2009 became the canonical example. The Royal Commission documented behaviours fire researchers had read about but rarely seen. The Kilmore East fire generated a pyroconvective column — a fire that lifts so much hot air it produces its own thunderstorm extending into the stratosphere. Embers landed up to 35 kilometres downwind, starting new fires faster than they could be tracked. The Marysville fire moved through forest at speeds that gave residents minutes rather than hours to evacuate. The Commission concluded that the conventional advice — stay and defend or leave early — had broken down because the leave-early window had closed faster than anyone expected.
The 2018 Camp Fire in California was a different kind of disaster. The fire ignited on 8 November near Pulga, sparked by a Pacific Gas and Electric transmission line. By midday it had reached the town of Paradise, 11 kilometres away. The town's residents, mostly older, had limited routes out. Roughly 27,000 people tried to evacuate on roads designed for everyday traffic. The fire moved at one football field per second. By the time it slowed two days later, 85 people were dead and most of Paradise had been incinerated. PG&E was found criminally liable and pleaded guilty to manslaughter charges in 2020.
03A century of suppression
The American approach was set by the Great Fires of 1910 a series of August fires that burned three million acres of Idaho and Montana and killed 87 people. The young United States Forest Service took the disaster as evidence that wildfire was an enemy to be defeated. The 10 a.m. policy, adopted in 1935, committed the agency to extinguishing every fire by 10 a.m. the day after it was reported. Smokey Bear was launched in 1944. The infrastructure that supported this approach became one of the most capable emergency response networks in any country.
The policy worked, in its own terms, for decades. Annual area burned in the American West dropped from roughly 8-10 million hectares in the early 20th century to under 1 million by the 1960s. What it could not do was eliminate fire from forests that had evolved with frequent low-intensity burning. Ponderosa pine forests of the Southwest had historically experienced fires every five to fifteen years ground-level burns that consumed litter, shrubs and small trees while leaving large mature trees unharmed. Fire suppression interrupted this rhythm. The forests filled with the small trees and accumulated litter that previous fires would have consumed.
04What was forgotten
The pre-colonial fire regimes of North America, Australia, and many other regions involved deliberate burning by indigenous people. In Australia, Aboriginal fire practices had been used for tens of thousands of years cool fires set in early dry season conditions, mosaic burning that left some areas unburned as refugia, fires timed to particular ecological cues. European settlers disrupted these practices, both by displacing indigenous populations and by treating fire as an enemy. Bill Gammage's 2011 book The Biggest Estate on Earth documented how thoroughly Aboriginal Australians had managed the continent's vegetation through fire.
Similar practices existed across North America. The Karuk and Yurok of northern California, the Apache of the Southwest, the nations of the eastern woodlands, the prairie peoples all used fire as a primary tool of land management. The eastern North American forests that European settlers encountered in the 17th century were cultural landscapes maintained by burning. The decline of indigenous fire practice removed the dominant management regime for ecosystems that had evolved with it.
05Conclusion
The fires of the last fifteen years are not unprecedented in the geological record, but they are unprecedented for the lifespan of modern industrial societies. The 2009, 2018, 2019-2020, 2023 and 2025 events form a pattern that is not yet finished. Fire-weather conditions are becoming more frequent. Fuel loads built up by a century of suppression are still on the ground. Human settlement continues to expand into the wildland-urban interface where most of the loss occurs. The trajectory is not mysterious. It is documented across thousands of papers.