"We are creating the fiery equivalent of an ice age": humans have plunged the Earth into a "pyrocene"

Firefighters battle a fire in the Palisades, Los Angeles, January 11, 2025. (Photo credit: Peyman Fakhraei/Middle East Images/AFP via Getty Images)

Los Angeles is on fire, but it is not alone. In recent years, fire disasters have engulfed cities in Colorado, the southern Appalachians, and the islands of Maui, as well as Canada, Australia, Portugal, and Greece. What remains is smoky.

Is this yet more evidence of a future that is not only terrifying but also strange, with no connecting narrative between the past and the present, or is it a harbinger of what is to come?

I am a fire historian, and my answer is that we have both a narrative and an analog. The narrative is the ongoing history of humanity and fire, a partnership that spans our entire existence as a species. The analog is that humanity’s fire practices have become so extensive, especially in recent centuries, that we are creating the fire equivalent of an ice age.

Fire as an organizing principle

Humanity and fire have shaped the Earth since the end of the last ice age, about 11,500 years ago. Overall, these changes have made landscapes more susceptible to fire.

The scale is significant. Recent research suggests that massive depopulation, particularly in the Americas, which removed the torch and allowed forests to reoccupy the land, thereby trapping atmospheric carbon, may have even contributed to the planet’s Little Ice Age from the mid-16th to mid-19th centuries.

But there were still limits. Fire and life had co-evolved over 420 million years, and ecological constraints and balances limited how far humanity could spread fire within the constraints of natural landscapes.

The process has certainly accelerated and changed character with the massive burning of fossil fuels, or what we might call lithic landscapes. This burning transcends old boundaries: it can happen at any time and in any place, and its residues are difficult to fit into the old ecosystem. By heating the atmosphere, it is a major cause of climate change, which in turn generally creates more favorable conditions for wildfires.

Equally important, the transition to a fossil fuel-based civilization has had an impact on how people live on the land, how they design cities and suburbs, how they shape living landscapes through agriculture and nature reserves, how they generate and transmit energy, and what methods of fire they use.