Pyrofutures 2025 [Part I]
Framing the future of wildfires now
Wildfire activity worldwide since 2018
Melissa Sterry January 19 2025
Several years since Panarchistic Architecture was first published, its projections on the near term future of wildfires in the contiguous United States, wider North America, and worldwide have come to pass. As had been anticipated, a confluence of factors culminated in a perfect fire storm propagated by both feedback loops within the Earth’s climate, hydrological, meteorological, and ecological systems, in concert with human activity, both intentional and otherwise. Now as throughout the period in which the data that informed the thesis was aggregated and analysed, the matter that multiple metrics and approaches are used across wildfire science to assess wildfire activity has led to conflicted positions within the wider scientific community, as different conclusions are drawn in response to different data sets. Though press and media reporting on wildfire activity has increased, again, now as then, all too many articles rely on assumptions informed by partial perspectives on this highly complex phenomena. Understanding how wildfire’s behaviour is changing requires analysis of diverse data, and both contemporary and historical. Contextualisation is critical, because wrong assumptions can easily be drawn from short-term trends, and especially whereupon the complexity of fire regimes is not accommodated in analysis. While awareness of fire ecology and wildfire’s role in the ecosystems of the regions to which it is native has increased, mis-information continues to abound, as Clements linear succession overshadows later studies that disproved the validity of the climax community model.
Globally, the causations of wildfire ignition have remained consistent with those of the preceding period, with lightning the primary ignition source in boreal forests (Janssen, T, A, J., et al, 2023), which accounted for 70% of tree loss cover from wildfires between 2001 - 2023, human action, including land clearance for agricultural expansion the primary ignition source in tropical forests (MacCarthy, J., et al, 2024) and in areas within and adjacent to the wildland-urban-interface (NIFC, 2024). Now, as then, the shift in wildfire activity is highly heterogeneous, both in terms of the annual acres burned, and the shifts in wildfire intensity, severity, and behaviour across the different biome types and geographic regions. We continue to see some fire-adapted areas experience less wildfire activity than typical of their historical fire regime, such as in Africa’s grasslands (Jones et al., 2024), while others experience markedly greater activity, be that by frequency, intensity, or both. Nonetheless, data shows that between 2001 and 2023 tree cover loss in boreal forests averaged an increase of roughly 3.6% annually (MacCarthy, J., et al, 2024), and between 2001 - 2019 the overall area burned globally by forest fires increased by around 5.4% per year (Tyukavina, A., et al, 2022). Furthermore, the period was punctuated by several record breaking wildfires across forests and shrublands in the circumpolar region, and in Temperature, and Mediterranean type climate regions. Throughout, annual fire extent and tree mortality remained inconsistent due to factors including seasonal instability in precipitation, temperature, and humidity levels.
In line with predictions (Sterry, M, 2018, 2019), climate feedbacks that contributed to extreme wildfires in the last several years included higher than average annual temperatures, drought conditions, and resultant reduction in moisture-levels in biomass, thus lower resilience to wildfire and higher tree mortality rates, as exemplified by the underlying causations of the fire complexes that engulfed Canada in 2023, where nearly 7.8 million hectares of trees burned, releasing nearly 3 billion tones of CO2 in the process (MacCarthy, J., et al, 2024). These fires significantly contributed to 16% jump in fire carbon emissions in the 2023 - 2024 fire season, despite a slight dip in overall acres burned (Jones et al, 2024).
Current annual CO2 emissions from wildfire averaging around 5-8 billion tonnes globally (Our World in Data, 2024), the increases in CO2 emissions from wildfires suggests the vicious circle of fire and climate feedbacks is well underway. While some mainstream press and media have now started to reference climate whiplash, the wider wildfire and climate feedback loops have been largely overlooked, from the link between insect and disease infestations, drought, and tree mortality to ash fallout’s impact on the albedo of glaciers and ice sheets, to the agency of wildfire to impact on meteorological and thus hydrological systems. Additionally, press and media narratives, and with them, wider dialogue around wildfires typically over-simply their nature, tending towards politicised and polarised perspectives which focus on whichsoever interpretation of events suits the agenda of the author. Meanwhile, wide-ranging data evidences signals historically tied to the destabilisation of the climate system and the advent of a new fire age that sees wildfire become the primary factor in discerning our environmental futures at scales both local and global. As had been anticipated (Sterry, 2018), changes in the fire regimes of some regions now brings into question whether some forests that currently serve as carbon sinks will rapidly shift to becoming carbon sources, while also experiencing such scale of change in their biomass assemblies - and both in terms of species type and population size - as heralds the early onset of a new ecological era.
Current carbon sinks turning into near-future carbon sources presents a policy as well as practical problem, given that forests are specified as central to delivering on national net zero targets of many nations (Smith et al., 2023). While estimates vary, framing the extent to which extreme wildfire activity could increase annual carbon emissions, Jones et al estimated in 2024 that, ‘by the end of the century, events of similar magnitude to 2023 in Canada are projected to occur 6.3–10.8 times more frequently under a medium–high emission scenario (SSP370).’ Wildfire’s influence spanning myriad aspects of Earth’s biotic and abiotic systems, and both local and global in extent, while humanity may have the means to contain some individual fires, we are far from having the ability to contain fire’s impacts more generally. The innate complexity of wildfire’s causations and effects, and the fact that though it is vital to the reproductive and wider processes of fire-adapted ecosystems, yet destructive to the economic and wider systems upon which many communities are built, underpins a culture in which wildfire remains largely perceived as foe not friend. Here, as in the 2018 thesis, the qualitatively distinct nature of wildfire in the wildlands to which it is indigenous, and in the built settlements to which it is not, undermines the decision to dis-entangle these wildfire types. While wildfire frequencies and intensities - and thus severities - are changing in wildlands, and these changes are significantly influenced by humans factors including but not limited to anthropogenic climate change, spread of invasive species, fire suppression, human ignitions - both accidental and arson, the some 420 million year history of fire on Earth, and that of the plants that have evolved to live with it - the pyrophytes - makes evident that though species distribution may change, and some landscapes transform from one biome type to another, Life will persist. In the years, decades, centuries, and millennia ahead, for so long as Earth remains inhabitable by carbon-based life forms, those life forms will live on, just not necessarily in the same form as they do now.
Both the above referenced, and with it wider data on climate and wildfire trends, suggest that human settlements both within and beyond fire-prone habitats will come under increasing threats from wildfires including both those within the immediate vicinity of the fires, and those that spread far futher afield - from heighten risk of loss of lives, property, and livelihoods from combustion, debris flows and other geological failures caused by factors including but not limited to soil erosion, to issues of pollution including air pollution, nano and micro plastics pollution, and other displacement of chemicals toxic to human and other life due to the combustion of man-made materials during wildfires that spread to buildings and other built structure. These issues are discussed in a separate Pyrofutures 2025 piece, which as in the 2018 thesis, discusses the wide-ranging factors driving changes in wildfire frequencies, intensities, and behaviours in and adjacent to the wildland-urban-interface. Though fire in the wildlands and peri-urban and urban landscape are intimately related, there are nonetheless distinct variances in the threats they pose to both human and non-human life.
The Future of Fire in the USA
A walk around the forests of California makes evident that factors including multi-year droughts and bark beetle infestations have left ample fuel for future wildfires to burn and burn intensely. In Southern California, no field study is required to gage the sheer scale of the die-off of older oaks in particular. While studies have shown that climate change and insect infestation are a primary cause of tree mortality (Hood and Reed, 2024), further factors are in play, including the fact that some trees, and in particular some older oaks, have come to the end of their natural life, and in some areas bark beetles have been inadvertently spread as infested timber is moved, be it for fire wood harvesting, thinning or more. Satellite and other surveys of biomass state, including field observations, have made evident that tree mortality across both California and the wider Western United States in tandem with the increase in mean average temperatures, as exemplified by 2024, in which they exceeded pre-industrial temperatures by 1.6°C (WMO, 2025), will contribute to more frequent and intense wildfires, and changes in historical fire regimes. These changes in wildfire’s expression in the landscape will cause ecological regime shifts, which will influence future wildfire activity. As with changes in water cycles, these changes in fire cycles will in turn cataylse other feedbacks in the Earth systems.
“The global average surface temperature was 1.55 °C (with a margin of uncertainty of ± 0.13 °C) above the 1850-1900 average, according to WMO’s consolidated analysis of the six datasets. This means that we have likely just experienced the first calendar year with a global mean temperature of more than 1.5°C above the 1850-1900 average.” WMO, 2025
As in the earlier part of the 21st century and, before it, the 20th century, wildfire activity in the U.S. has been heavily influenced by human activity. The legacy of wildfire suppression lives on, as does the problem of conflicts of commercial, political, societal, and environmental interests and the inability of some communities to work to collective not individual gain. While mis-information has plagued wildfire policy and the debates that shape it since the 1800s, the sheer speed and scale at which misleading content can be produced, widely distributed, and presented in ways that can seem convincing has undermined efforts to educate the wider populous on the workings of wildfire and the ways in which its behaviours are changing. Now, as of past, public interest in wildfire fluctuates depending on its visibility in the press and media, becoming prominent when fire complexes are spreading in and in close proximity to the wildland-urban-interface, such as in Los Angeles firebelt suburbs, where a fire complex continues to burn having ignited on January 7th 2025. While the nature of wildfire in the built environment is qualitatively distinct from that of wildfire in the wildlands, these latest fires have shown how the two can be confused both within the minds of the press and media, and the readers that rely on their content as a point of reference.
In 2024, California remained the most fire-prone state in the U.S. (Dillion, G, K., et al, 2023). Human encroachment on wildlands in both California and the wider U.S., having continued apace since 2018, development in the wildland-urban-interface has continued at a rate of around 2 million acres a year, with nearly 99 million people living in the WUI nationally (ICC, 2025). Now, as in 2018, that’s around one-third of the U.S., population, but, while events such as the January 2025 Los Angeles wildfire complex has raised awareness of the risk this creates for humans and their property, awareness of the risk continued expansion into wildlands presents to pyrophytes - plants that evolved to live with wildfire, and to other members of the Kingdoms of Life that have done likewise, remains low. As common since the Yellowstone fires of 1988, copious press and now commonly social media posts wrongly suggest that wildfire ought not burn through the very landscapes to which it is native, and a catalyst for regrowth and renewal. However, given the scale and extent of the damage to lives, property, and livelihoods caused by the Los Angeles fire complex - an event akin to the Great Fire of London, or of Rome or Chicago, it is probable that the complex will catalyse changes to land management in the district, if not across the state of California, which, for better or worse, will have both a quantitive and qualitative impact on the frequency, intensity, and behaviour of wildfire. In theory, the event could lead to policies that seek to reduce accidental ignitions in wildlands, such as mandating earlier interventions during fire weather to reduce the likelihoods of ignition from power lines or other infrastructure in fire-prone areas. In practice it may lead to policies that seek to increase fire suppression, which could lead to a build up of biomass that increases the intensity of wildfires when they ignite. Alternatively, it could lead to an increase in prescribed fire, which may reduce the threat of extreme wildfire in some areas, but which can have limited effect given the speed at which some biomass grows, including invasive grasses (McGranahan, D, A., et al, 2012), and which can escape the intended burn area, and become a hindrance not a help (Wier, J, R., et al, 2017). In any event, history suggests that the road ahead will be littered with heated debates, predictable biases, and a general inability to accommodate for the complexity of the challenge in hand.
However, as in 2018, the fire future of the U.S. sits within a range of possibilities. In the event there are no major disruptions to the global climate, such as a significant increase in the amount of volcanic activity, i.e. a number of large VEI 6 eruptions, or a VEI 7, and the Atlantic Meridional Overturning Circulation (AMOC) continues to circulate, we might reasonably assume that we’re entered the era that Stephen Pyne has described as the Pyrocene. Within this scenario, wildfire activity in the U.S. will continue to increase in wide-ranging regions, and particularly in boreal forests and other biomes with high density of biomass. As discussed in the thesis, within this scenario Southern California sees a rise in wildfire frequencies and intensities and its fire regimes start to shift. Some plant and animals species would become more populous in some places, and vice versa, and we would start to see ecological transitions underway by around mid-century - evolution would unfold before our eyes, and doubtless bring some surprises as we saw some species adapt in potentially unpredicted ways, both physiologically and behaviourally. Northern California would see a significant increase to wildfire activity and some carbon sinks turning to sources. Oregon would likewise see a significant shift, as would some other densely forested states, and particularly those on the Western side, as further up the continent, Canada experiences the same. This scenario would likely be met by sharply divided public opinion, as some choose to accept the changes, and others seek to try and conserve the environmental parameters of the latter part of the Holocene, and more specifically those of living memory.
As discussed in the thesis, the impacts of climate change on plant productivity are non-linear, with some members of some species in some contexts having enhanced photosynthesis in response to higher temperatures, and others vice versa. While a study published in 2021 stated that combined remote sensing, machine learning, and terrestrial biosphere models found that plants photosynthesised at a 12% higher rate from 1982 - 2020 in response to global CO2 concentrations in the atmosphere growing from 360 parts per million (ppm) to 420 ppm, the article was retracted, and the picture of plant productivity in response to climate change remains patchy. Arguably, that’s to be expected. Life responds to disruption in diverse ways and the impacts of climate change are uneven. Added to that, the evolutionary pressures upon species populations also vary from place to place, impacted by factors including but not limited to land-use change, wider issues of pollution including air, light, noise, plastic, and other threats, invasive species spread, poaching, and more. Put another way, Life might try to ‘find a way’ to quote one of the world’s most famous fictitious mathematicians (Crichton, 1990), but some life has more obstacles in that way than others. Consequently, just as occurs more generally with wildfires, how ecosystems response will likely be mosaical and non-linear.
Whatsoever the fire future of the U.S., many, if not all of its pyrophyte species will likely persist, just not necessarily in the same distribution as today. From lineages that evolved during periods many times more combustible that today, in addition to the functional traits we affiliate with them, it’s possible that some may have the capacity for rapid evolution in the face of abrupt climatic and wider environmental change. They, like all life, have the capacity for variety in their genetic expression and they may well present higher levels of resilience than has been evident in this most recent of geological epochs. While invasive species are influencing many fire regimes in and beyond California, plants that evolved to live with wildfire are not merely resilient to fire, but are more resilient to environmental conditions with which it’s coupled, including aridity and heat, than are species from cooler climates. In any event, though some areas of California and the Western U.S. are likely to experience higher average temperatures, lower average humidity, and greater variance in precipitation, the matter that the high diversity of terrain creates microclimates renders it unlikely that wide regions will experience desertification of the kind that is too hostile to support biodiversity in the state which, presently, has the highest level of biodiversity of any in the contiguous United States.
Wildfire Statistics USA 2018 onwards
Tree cover loss, tree mortality, acres burned
The statistical data on wildfire frequency and firespread in the United States since 2018 illustrates the sometimes high variance between wildfire activity from year to year. However, the scale and extent of tree cover loss and mortality indicate that even accounting for old growth die off, tree mortality rates are high enough that in tandem with the increase to mean average global tempertures, the shift from seasonal to sometimes year-round fire weather, and the instability in seasonal precipitation, suggest an upward trend in fire frequencies and/or intensity in some regions is likely in the years and decades ahead.
Between 2001 - 2023, the United States lost 12.7 million hectares of tree cover from wildfires (MacCarthy, J., et al, 2024)
Between 2020 - 2021, California lost over 700,000 hectares (1.73 million acres) of tree cover due to fire (Global Forest Watch)
Between 2010 - 2023, an estimated 237 million trees died in California due to water and heat stress, and insect and disease infestation (OEHHA, 2024)
Between 2012 - 2016 an estimated 147 million trees died in California due to multi-year drought and bark beetles outbreaks (Hood, S, M., and Reed, C, 2024)
In 2018, 58,083 wildfires burned across the U.S., consuming approx. 8,767,492 (NIFC, 2024)
In 2019, 50,477 wildfires burned across the U.S., consuming approx. 4,664,364 acres (NIFC, 2024)
In 2020, 58,950 wildfires burned across the U.S., consuming approx. 10,122,336 acres (NIFC, 2024)
In 2021, 58,985 wildfires burned across the U.S., consuming approx. 7,125,643 acres (NIFC, 2024)
In 2022, 68,988 wildfires burned across the U.S., consuming approx. 7,577,183 acres (NIFC, 2024)
In 2023, 56,580 wildfires burned in the U.S., consuming approx. 2,693,910 acres (NIFC, 2024)
In 2024, 61,685 wildfires burned in the U.S., consuming approx. 8,851,142 acres (NOAA, 2024)
In January 2025, 197 wildfires have burned in California, consuming 40,602 so far (CALFIRE, 2024)
References
CALFIRE (2025) https://www.fire.ca.gov/incidents/2025
Crichton, M (1990) Jurassic Park. Alfred A. Knopf, U.S.
Dillon, G. K., et al (2023) Spatial datasets of probabilistic wildfire risk components for the United States (270m) (3nd Edition)
Global Forest Watch (2024) https://www.globalforestwatch.org/dashboards/country/USA
Hood, S, M., and Reed, C (2024) Trees dying, dangers rising: Major tree mortality events rapidly increase forest fuels and snag hazards, USDA, Forest Service
Jones, M, W., et al (2024) State of Wildfire 2023 - 2024, Earth System Science Data
Janssen, T, A, J., et al (2023) Extratropical forests increasingly at risk due to lightning fires, Nature Geoscience volume 16, pages1136–1144
Keenan, T. F., et al. (2021) A constraint on historic growth in global photosynthesis due to increasing CO2, 8 December 2021, Nature.
MacCarthy, J., et al (2024) The Latest Data Confirms: Forests Fires are Getting Worse, World Resources Institute
McGranahan, D, A., et al (2012) An Invsaive Cool-season Grass Complicated Prescribed Fire Management in Native Warm-season grassland, Natural Areas Journal, Volume 32(2) 2012
National Interagency Fire Centre (2025) Wildfires and Acres: Total Wildland Fires and Acres (1983 - 2022)
NOAA National Centers for Environmental Information, Monthly Wildfires Report for January 2025
OEHHA State of California (2024) Forest tree mortality https://oehha.ca.gov
Our World in Data (2024) Annual CO2 emissions, ourworldindata.org
Smith, S (2023) State of Carbon Dioxide Removal, 1st Edition, DOI 10.17605/OSF.IO/W3B4Z
Sterry, M, L (2018) Panarchistic Architecture: Building Wildland-Urban Interface Resilience to Wildfire through Design Thinking, Practice and Building Codes Modelled on Ecological Systems Theory, PhD thesis, University of Greenwich
Sterry, M, L (2019) [Re]Generation[s]: Once in Many Lifetimes Opportunities, Closing Keynote, Canadian Institute of Planners centenary conference, Ottawa, July 6th 2019
Tyukavina, A., et al (2022) Global Trends of Forest Loss Due to Fire from 2001 - 2019, Front. Remote Sensing., 15 March 2022, Volume 3 - 2022
Weir, J, R., et al (2017) Prescribed Burning: Spotfires and Escapes. Oklahoma State Univerity fact sheet, August 2017.
World Meteorological Organization (2025) WMO confirms 2024 as warmest year on record at about 1.55°C above pre-industrial level. https://wmo.int
Citation
Sterry, M, L (2025) Pyrofutures 2025 [Part I]: Framing the future of wildfires now - wildfire activity worldwide since 2018, PanarchicCodex.com
