The Pyrocene

1. We have entered the Pyrocene, a planetary Fire Age equivalent to the Ice Age

Add up all these fire influences—those directly through flame and those indirectly through smoke, removed fire, fire-enabled land use, and a warming climate—and you have the contours of a planetary fire age, the fire-informed equivalent of an ice age.

A new geological epoch. The Pyrocene represents a profound shift in Earth's history, where human fire manipulation has become the dominant force shaping the planet. Just as ice sheets sculpted the Pleistocene, fire is now the primary ecological signature reorganizing our climate, oceans, and biotas. This fire-centric perspective redefines the Anthropocene, illustrating how our cumulative fire practices have created a self-sustaining fire age.

The fire-ice analogy. The transition from the Pleistocene to the Pyrocene is a mirror image of planetary forces. While ice once locked up water, lowered sea levels, and drove extinctions through cold, fire is now melting that ice, raising sea levels, and driving a sixth mass extinction through heat. The ecological and physical disruptions of our current era match the scale of the ancient glaciations.

• Ice is exclusive and physical; fire is interactive and biological.
• Glaciers carved outwash plains; mega-fires cast global smoke palls.
• The Pleistocene stockpiled carbon; the Pyrocene is rapidly liberating it.

An autocatalytic future. Like propagating ice sheets that reinforced their own cold climates, our binge-burning of fossil fuels is creating a self-reinforcing cycle of heat and flame. We have constructed a world that actively encourages more fire, and we must now learn to inhabit it. The past remains our prologue, offering the only narrative and analogue to navigate this strange, no-analogue tomorrow.

2. Earth is uniquely a fire planet because fire is a creation of life

Among planets fire is as rare as life, and for the same reason: fire on Earth is a creation of the living world.

Life enables combustion. Fire is not merely a physical force imposed on the Earth; it is a biological phenomenon that coevolved with terrestrial life. For fire to exist, it requires oxygen and fuel, both of which were created and are continuously replenished by living organisms. Other planets may have sparks or methane, but only Earth possesses the biological matrix required to sustain free-burning fire.

The chemical feedback. The Earth's atmosphere is a highly volatile mixture primed to burn, maintained by a delicate balance between photosynthesis and respiration. Fire acts as a fast decomposer, taking apart what photosynthesis puts together and recycling nutrients back into the soil. This relationship is so deeply integrated that geologic eras with high oxygen levels correspond directly with abundant fossil charcoal.

• Oxygen must remain between 14% and 35% for fire to occur without consuming the planet.
• Fossil charcoal (fusain) proves that fire has been continuous for 420 million years.
• Plants have evolved specific traits, like thick bark and serotinous cones, to exploit fire.

A biological catalyst. Unlike hurricanes or earthquakes, fire is a biochemical reaction that feeds on its organic matrix. It behaves more like a fast-moving herbivore or a spreading contagion than an inert physical disturbance, acting as a broad-spectrum catalyst for evolutionary selection. Organisms do not just adapt to fire; they actively shape the fire regimes that govern their survival.

3. The history of fire is defined by three distinct phases: First, Second, and Third Fire

Where once there was one kind of fire on Earth, then two, there are now three.

The three-body problem. The history of planetary burning is an ecological three-body problem involving natural fire, human-managed fire, and industrial combustion. These three fires have competed, complemented, and colluded over time, ultimately flipping the Earth's fire system into a feral state. Understanding their interactions explains the paradoxes of our current global fire crisis.

First and Second Fire. First-fire is the fire of nature, sparked by lightning since plants first colonized land. Second-fire emerged when hominins domesticated the flame, using torches to cook food and manage living landscapes, thereby expanding fire's reach into wet-dry biomes. Together, they operated within the natural constraints of fuel, season, and weather.

• First-fire: Natural, ecological, bounded by fuel and weather.
• Second-fire: Anthropogenic, domesticating, used for hunting and agriculture.
• Third-fire: Industrial, mechanical, burning fossilized lithic biomass.

The unhinged Third Fire. Third-fire represents a qualitative break from ecological limits because its fuel source is virtually infinite. By burning fossilized biomass from the geologic past, humans have decoupled fire from seasonal rhythms, creating a crisis of too much combustion and too few sinks. This industrial fire has unhinged not only the climate but our ancient, domestic relationship with flame.

4. Cooking was the foundational pyrotechnology that domesticated both humans and fire

Thanks to cooking, a dependence on fire became coded into hominin DNA; thanks to favorable conditions at the end of the last ice age, second-fire steadily spread everywhere humans did.

Evolutionary tipping point. Cooking served as a process of external predigestion that fundamentally altered human biology. By chemically enriching carbohydrates and softening fibers, cooked food allowed early hominins to develop smaller guts and larger brains. This nutritional advantage became coded into our DNA, making humans the only species that cannot survive without fire.

The first domestication. Fire was not a tool that could be shelved; it was a living relationship that required constant feeding, housing, and tending. The campfire became the center of social organization, language transmission, and the physical structure of the human home (the domus). To keep the home fires burning became the ultimate emblem of human endurance and community.

• Cooking reduced the physical energy required for digestion.
• Tending fire forced hominins to organize labor and gather fuelwood.
• The hearth served as the evolutionary cradle for human culture and myth.

From hearth to landscape. The discipline learned at the campfire was eventually projected outward onto the wider world. Having domesticated fire in the hearth, humans used the torch to domesticate the surrounding landscape, turning wild ecosystems into habitable niches. This mutual assistance pact allowed both humans and fire to expand into realms otherwise inaccessible to life.

5. Aboriginal and agricultural fires shaped the Earth's "second nature"

The open forest lands nearest to Sydney yielded to thick forests of young trees, where, formerly, a man might gallop without impediment, and see whole miles before him.

Firestick farming. Indigenous peoples used fire systematically to manage ecosystems, a practice famously termed "firestick farming." By burning early, light, and often, they created open, mosaic landscapes that maximized biodiversity, facilitated travel, and prevented catastrophic wildfires. These fires were set in harmony with seasonal cues, replacing natural lightning fires with a predictable, human-guided regime.

Agricultural fire-fallow. Agriculture scaled up this pyric manipulation through swidden (slash-and-burn) cultivation and pastoral burning. Fallowing was not a waste of land but a deliberate method of growing fuel to be burned, using the ash to fertilize crops and clear weeds. This circulating system dappled the land with patches of various ages, creating a rich reservoir of biodiversity.

• Swiddening created a dappled, highly biodiverse forest mosaic.
• Pastoralists used fire to keep pastures open and stimulate fresh forage.
• Agricultural fire acted as a broad-spectrum ecological catalyst.

A soft ecological weld. These traditional practices operated within the natural constraints of weather, seasons, and fuel availability. Second-fire did not destroy first-nature but negotiated with it, creating a stable, fire-adapted "second nature" that persisted for millennia. The removal of these regular, low-intensity fires has led to ecological degradation and fuel accumulation.

6. The Pyric Transition shifted our fuel source from living to lithic landscapes

The shift required a suitable combustion chamber; this first emerged with the steam engine over the course of the eighteenth century.

Unbounding the fuel. The Industrial Revolution initiated a "pyric transition" by replacing living biomass (wood and peat) with fossilized lithic biomass (coal, oil, and gas). This transition liberated humanity from the ecological limits of the surface world, allowing us to burn fuel regardless of season, weather, or the rate of biological growth. It granted us unprecedented, concentrated power.

The machine age. By encasing fire within mechanical chambers like the steam engine, we transformed fire from an ecological process into a source of raw, concentrated power. This mechanical sublimation distanced humans from real flame, turning fire into an invisible, industrial utility. We traded the messiness of foraging and breathing smoke for the efficiency of the internal combustion engine.

• Anthracite coal contains more than twice the caloric value of dry wood.
• Lithic burning is limited only by our ability to extract and transport fuel.
• The transition replaced the search for fuel sources with a search for effluent sinks.

The intellectual dark age. As working fires disappeared from daily life, modern science deconstructed fire into its physical components—chemistry, thermodynamics, and electromagnetism. This reductionist approach caused a cultural amnesia, erasing fire's biological and historical role from our collective knowledge. Fire was removed from both our lived experience and our academic disciplines, treated as a hazard rather than an essential ecological process.

7. Fossil fuel combustion has unhinged the global climate and created a "third nature"

Taking fuels out of the geologic past, burning them in the present, and releasing their by-products to a geologic future—this is fire’s new narrative arc and one of the grand markers in Earthly history.

A geological transfer. Third-fire does not recycle carbon within the biosphere; instead, it performs a massive, one-way transfer of ancient carbon into the modern atmosphere. This industrial effluent has acidified the oceans, melted glaciers, and fundamentally disrupted the global climate. We are taking fuel from the geologic past, burning it in the present, and releasing it into the geologic future.

Creating a third nature. The power of fossil fuels allowed humans to construct a highly artificial "third nature" of steel, concrete, and electricity. We replaced the ecological work of fire with chemical fertilizers, synthetic pesticides, and heavy machinery, further simplifying and destabilizing ecosystems. This transition has removed working flames from our built environments while amplifying our indirect impact on the planet.

• Industrial agriculture uses oil-derived chemicals to bypass natural fire cycles.
• Urban centers are built of materials that have already passed through industrial flame.
• Global transport networks connect remote resources, accelerating land clearing.

The globalized plume. The consequences of third-fire are no longer local; they are globalized through the atmosphere. Emissions from coal plants and internal combustion engines act as global performance enhancers, drying out forests and intensifying wildfires thousands of miles away. The global climate has become a subnarrative of our industrial fire history.

8. The fire suppression paradox has created a dangerous deficit of good fire

The Earth’s fire crisis, that is, was not just about the bad burns that trash countryside and crash into towns. It was equally about the good fires that had vanished because they were actively extinguished or no longer lit.

The suppression paradox. For over a century, modern forestry agencies used fossil-fueled machinery to wage a war of total suppression against landscape fire. However, removing fire from fire-adapted ecosystems causes a massive buildup of flammable underbrush, ensuring that when fires do return, they are uncontrollably violent. The more we try to exclude fire, the more destructively it returns.

The combustion deficit. By outlawing traditional burning and aggressively extinguishing natural ignitions, industrial societies created a severe "combustion deficit." The loss of regular, low-intensity "good fires" has degraded biodiversity, choked forests, and set the stage for modern megafires. The Earth's biota is disintegrating as much by tame fire's absence as by feral fire's outbreaks.

• Fossil-fueled bulldozers, air tankers, and pumps enabled total fire exclusion.
• Suppressing 98% of fires ensures the remaining 2% burn under the worst possible conditions.
• The wildland-urban interface places vulnerable communities directly in these high-fuel zones.

Feral flames. When we attempt to banish fire from landscapes that coevolved with it, we do not eliminate combustion; we merely trade tame, predictable fires for feral, catastrophic conflagrations. The disasters in California, Portugal, and Australia are the direct blowback of this failed strategy. We have replaced a steady regime of small, beneficial fires with a chaotic cycle of megafires.

9. To survive the Pyrocene, we must learn to live with fire by reintroducing it

As we ratchet down fossil fuel burning, we’ll have to ratchet up our burning of living landscapes.

A necessary renegotiation. Surviving the Pyrocene requires a fundamental shift from fighting fire to managing it. We must drastically reduce our burning of lithic landscapes (fossil fuels) while simultaneously increasing our deliberate burning of living landscapes through prescribed and cultural fires. We cannot simply remove fire; we must choose what kind of fire we want to live with.

Pluralistic fire management. There is no single solution to the fire crisis; we must deploy a cocktail of strategies tailored to specific landscapes. This includes letting remote wilderness fires burn, executing controlled burns to protect communities, and restoring Indigenous fire stewardship. We must replace the engineered precision of industrial suppression with the ecological variability of natural fire.

• Prescribed burning reduces fuel loads and restores ecological health.
• Cultural burning revitalizes Indigenous heritage and land management.
• Hardening communities with fire-resistant materials protects lives without suppressing nature.

Fire as a partner. Fire is a self-sorting, integrating process that can restore ecological balance far more efficiently than human engineering. By treating fire as an ancient partner rather than an enemy, we can navigate the challenges of the Fire Age and find the sparks of a better world in the ashes. We must reclaim our role as the keeper of the planetary flame.