The research team turned to lake sediments preserved within Croajingolong National Park, one of the most repeatedly burnt landscapes in southeastern Australia, to read the region’s environmental past. Lake sediments accumulate in annual and seasonal layers, trapping charcoal particles, pollen grains and eroded soil that together form a continuous archive of what grew on the land, how hot fires burned and how severely the ground eroded across centuries. By extracting cores from the lakebed and analysing these preserved signals layer by layer, the scientists reconstructed the past 1000 years of ecological change with enough resolution to distinguish the pre-colonial period, when Gunaikurnai people actively managed the landscape, from the post-colonial era, when that management ceased. The technique allowed the researchers to separate the influence of climate variability from the influence of land use, a distinction that shorter records spanning only the industrial era cannot reliably make.

What the sediment record revealed was a cascading sequence of changes that began with fire itself. Infrared spectroscopy of charcoal fragments preserved in the sediments provided a proxy for past fire temperatures, distinguishing the cool, low-intensity burns characteristic of cultural fire practice from the hot wildfires that followed. The record shows that after colonisation, fire temperatures rose sharply. Those hotter fires came first in the sequence, and they drove a four-fold surge in eucalypt cover, transforming what had been maintained as open woodland for centuries into dense, closed forest. As the canopy thickened and fuel accumulated on the forest floor, soil erosion in the catchment increased, providing independent physical evidence that the landscape had crossed into a fundamentally more disturbed state.

Critically, the researchers demonstrated that this ecological transformation predates human-driven climate change. Dangerous fire weather is not new to East Gippsland: climate records show that seasons comparable to those that produced the Ash Wednesday fires of 1983 and the Black Saturday fires of 2009 occurred repeatedly in the region before colonisation. Yet during those earlier episodes of severe fire weather, the open woodland maintained by Gunaikurnai cultural burning did not produce catastrophic fire. The fuel loads were simply too low. It was only after colonisation ended that active management, allowing forests to expand and thicken across the region, that the same dangerous weather conditions began translating into landscape-scale disaster. In the authors’ framing, colonisation loaded the landscape with fuel, and it is that loaded landscape that has handed control of fire to the climate.

Lead author Professor Michael-Shawn Fletcher, of the School of Geography, Earth and Atmospheric Sciences at the University of Melbourne, said the work provides scientific evidence for the value of cultural burning and the need to integrate Indigenous knowledge into contemporary fire management. When Country is cared for, he noted, climate does not dictate wildfire. For thousands of years, Gunaikurnai people cared for Country in what is now Croajingolong National Park through cultural burning, keeping much of the landscape as open woodland. The study’s conclusion is that most discussion of Australia’s wildfire crisis stops at climate change, but the new evidence shows what actually set the stage for it: forest expansion and thickening that loaded the landscape with fuel long before the climate began to shift.

The findings carry significant weight for Gunaikurnai Traditional Owners, whose fire practice, known as towera, is understood within their culture as an interrelationship embedded in the practical daily life of the Old Peoples on Country. Uncle Russell Mullett, a Gunaikurnai elder from the Gunaikurnai Land and Waters Corporation, explained that Country not treated with towera becomes extremely dangerous for Gunaikurnai people, animals and plants alike. He welcomed the study as firm scientific evidence supporting towera land management initiatives, giving Traditional Owners a powerful empirical basis for reinstating practices that colonial displacement interrupted. The collaboration between the university researchers and the Gunaikurnai Land and Waters Corporation itself models the kind of partnership the paper argues is essential, combining Western palaeoecological methods with Indigenous ecological knowledge accumulated over millennia.

Beyond its immediate implications for fire policy, the study mounts a direct challenge to one of environmentalism’s most influential ideas: the concept of wilderness. Croajingolong National Park has long been treated as pristine wilderness, land largely untouched by human hands, and that framing has shaped how it is protected. Yet the sediment record shows the opposite. The forest now cherished as natural is, in Professor Fletcher’s words, a product of colonisation, and it is that legacy that now imperils the forest’s very survival. The park is today one of the most fire-prone and repeatedly burnt parts of southeastern Australia, a status the research attributes not to its natural condition but to the absence of the management that once sustained it. Protecting landscapes by excluding the people who shaped them, the study suggests, may be an ecological strategy that actively undermines the ecosystems it aims to preserve.

The technical strength of the work lies in its multi-proxy approach. By combining charcoal morphology to identify fire occurrence, infrared spectroscopy of charred material to reconstruct fire intensity, pollen analysis to track vegetation composition and sediment accumulation rates to quantify erosion, the researchers built a mutually reinforcing picture of cause and effect across a full millennium. The sequencing matters: because the rise in fire temperature precedes the eucalypt expansion in the record, the data support a causal chain in which hotter fires promoted denser forest, denser forest increased fuel loads, and increased fuel loads amplified subsequent fire behaviour. This feedback loop, once initiated by the cessation of cultural burning, converted a fire-resilient open woodland into a fire-vulnerable forest, and it did so before atmospheric greenhouse gas concentrations began their modern rise.

The paper concludes that restoring cultural burning and supporting Traditional Owners to care for Country is an essential component of mitigating wildfire risk, not a cultural gesture but a practical, evidence-based intervention. As southeastern Australian forests face intensifying fire weather under a warming climate, the research suggests that reducing the vulnerability of these landscapes requires addressing the colonial land-use legacies that made them combustible in the first place. The message from Croajingolong is stark and, for fire management agencies, potentially transformative: the current crisis is not solely a climate story, and the tools for rewriting it have been present on Country for thousands of years, waiting to be returned to use.

Subject of Research: Long-term palaeoecological reconstruction linking colonial cessation of Indigenous cultural burning to increased wildfire risk in southeastern Australian forests

Article Title: Australia's wildfire crisis linked to colonial land-use change

Article References: Australia's wildfire crisis linked to colonial land-use change. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: bushfires, cultural burning, Indigenous land management, Gunaikurnai, Croajingolong National Park, eucalypt forests, palaeoecology, lake sediments, colonisation, climate change, fire management, Nature

The research, led by Michele Salis and Liliana Del Giudice of Italy’s National Research Council Institute of BioEconomy, together with colleagues from Spain, Iran and other institutions, focused on two time windows: a historical baseline from 1985 to 2014 and a near-future period from 2035 to 2064. The team drew on three state-of-the-art climate models from the Coupled Model Intercomparison Project Phase 6, known as CMIP6, namely ACCESS-ESM1-5, EC-EARTH3 and MPI-ESM1-2-HR, each run under three Shared Socioeconomic Pathways spanning low to very high greenhouse gas emissions. What sets this study apart is the resolution: the raw climate model output, which arrives at a coarse scale of tens of kilometers, was statistically downscaled to a grid of just one square kilometer using a two-step technique combining parametric quantile mapping with geostatistical regression, before feeding into fire danger calculations and fire spread modeling.

To quantify fire danger, the researchers applied the Canadian Forest Fire Weather Index System, the same harmonized method used across Europe by the European Forest Fire Information System since 2007. The FWI integrates daily maximum temperature, minimum relative humidity, wind speed and cumulative precipitation into a single rating of potential fire intensity, and it depends on three fuel moisture codes that track the dryness of fine fuels, duff and deep organic layers. The team also calculated the Daily Severity Rating, a metric that amplifies the influence of extreme FWI values and estimates how difficult a fire burning that day would be to suppress. Both indices were computed for every pixel of the island on every day of the two study periods, for each climate model and each emissions scenario.

The signal that emerged was consistent across all three models, though its magnitude varied. Under the historical baseline, days with very high FWI values were rare, concentrated almost entirely in the May-to-October fire season, when high and very high danger conditions already accounted for roughly 43 to 46 percent of days. By the 2035-2064 period, the picture shifts dramatically. Under the highest emissions scenario, SSP5-8.5, the EC-EARTH3 model projected that very high FWI days would more than double during the fire season, climbing from about 4.6 percent to 10.8 percent of days, while the ACCESS model showed a rise from 4.0 to 10.1 percent. Even the more conservative MPI model projected a near doubling, from 4.5 to 8.2 percent. The Daily Severity Rating told a parallel story, with very high severity days under EC-EARTH3 rising from 8.4 percent to 17.1 percent of fire-season days under the worst-case pathway.

Underlying these danger trends is a straightforward climatic mechanism. All models project warmer and drier conditions for Sardinia, with maximum temperature increases reaching up to about 3.3 degrees Celsius annually and 3.9 degrees during the fire season under high emissions. Precipitation declines across the board, particularly in western and central sectors of the island, and the number of rainy days drops markedly, especially during the hottest months, pointing to longer and more frequent dry spells that desiccate fuels. Intriguingly, the analysis of wind conditions on extreme danger days showed that the projected increase in very high fire weather comes mostly from more days with low and moderate winds rather than stronger winds, suggesting that rising temperatures and reduced rainfall, not windier conditions, will be the dominant drivers of intensifying fire risk.

But the study went a crucial step beyond danger indices. Weather alone does not make a wildfire; fires need ignitions, flammable fuels and terrain that allows spread. To capture those interactions, the team built a probabilistic fire simulation framework using the Minimum Travel Time algorithm, which computes the fastest possible paths of fire growth across a landscape and calculates spread rates with the Rothermel surface fire model, while crown fire initiation follows the Van Wagner approach. The researchers ran tens of thousands of simulated fire footprints, 50,000 under baseline conditions alone, at a fine 150-meter resolution, randomly drawing weather streams, wind directions and fire durations from frequency distributions derived for three weather zones covering northern, central and southern Sardinia. Ignition points were placed according to probability grids built from two decades of historical fire records, and fuel moisture inputs were anchored in field measurements collected on the island, including live fuel moisture values between 65 and 100 percent depending on vegetation type.

The hazard outputs are striking. Under historical conditions, the models simulated an average annual burned area of roughly 11,700 to 15,400 hectares, consistent with the observed mean of about 14,700 hectares per year, or 0.65 percent of the island’s surface. In the future simulations, that figure nearly doubles or more. Under EC-EARTH3 and SSP5-8.5, the average annual area burned jumps to approximately 33,590 hectares, a 250 percent increase over the baseline, while ACCESS projects more than 30,000 hectares per year under the two higher-emission scenarios. Crown fire area, a measure of the most intense and dangerous fire behavior in forests, rises from between roughly 730 and 1,060 hectares per year historically to as much as about 2,020 hectares per year under the worst-case combination of model and scenario.

Perhaps most important is where these changes unfold. Historically, burn probability hotspots have been concentrated in southern Sardinia, with annual burn probabilities exceeding 4 hectares per square kilometer in localized zones. The future projections show those hotspots expanding in both magnitude and extent, pushing into western and interior regions of the island. Under SSP5-8.5, much of the island shifts toward higher burn probability classes, with localized increases above 10 hectares per square kilometer in the main southern hotspot zones. Crown fire probability rises in parallel, with the most pronounced gains in southern and western Sardinia, where some areas reach values exceeding 8.5 hectares per square kilometer. This westward and inland expansion matters because those regions, including areas hit by major fires such as the Montiferru blaze of 2021, are already among the most fire-affected parts of the island, and inland zones lack the moderating influence of the sea that cushions coastal areas.

One of the study’s most thought-provoking findings is a caveat about what fire danger indices can and cannot tell us. Despite the systematic rise in FWI values, the simulated average flame length and average fire size did not increase consistently from the historical to the future period, partly because the extra extreme-danger days occurred disproportionately under low and moderate winds. The authors stress that extreme fire weather is necessary but not sufficient for large wildfires: a blaze must also start, escape initial suppression and find continuous fuels to spread across. Simply equating projected FWI maps with future fire risk, as some earlier studies have done, therefore overstates the certainty of the picture. Probabilistic spread modeling, which integrates weather, ignitions, fuels and landscape connectivity, provides a far more realistic estimate of where fire exposure will actually grow.

The researchers acknowledge limitations, notably that fuel layers and ignition patterns were held constant to isolate the climate signal, an assumption that could either understate or overstate future hazard depending on how land abandonment, fuel accumulation and fire activity themselves evolve. Still, the message for the Mediterranean is unambiguous. The authors argue that suppression-oriented strategies alone cannot cope with the projected intensification, and they call for proactive, integrated risk management: landscape-scale fuel treatments, grazing, prescribed burning, fire-resilient land-use mosaics and spatial planning that accounts for expanding fire-prone zones. As record seasons sweep southern Europe, with more than one million hectares burned across the EU in 2025 alone, Sardinia’s high-resolution glimpse of the future offers both a warning and a practical roadmap for landscapes on the front line of a warming world.

Subject of Research: Projected effects of climate change on wildfire danger and hazard in Sardinia, Italy

Article Title: Climate change will reshape future wildfire danger and hazard in Sardinia, Italy

Article References: Climate change will reshape future wildfire danger and hazard in Sardinia, Italy. (n.d.). https://doi.org/10.1007/s11069-026-08320-5

Image Credits: AI Generated

DOI: 10.1007/s11069-026-08320-5

Keywords: wildfire, climate change, Sardinia, Mediterranean Basin, Fire Weather Index, burn probability, fire spread modeling, CMIP6, SSP scenarios, crown fire, Daily Severity Rating, fire management