Background Wildfire spread modeling is essential for understanding fire behavior and improving mitigation strategies. However, many existing models struggle to capture the irregular and scale-dependent nature of wildfire perimeters.Aims This study introduces a fractal-based simulation framework for modeling wildfire propagation, integrating terrain and weather-related environmental parameters.Methods We applied a modified twindragon fractal structure to simulate wildfire spread across geographic information system (GIS)-derived maps of slope, aspect, land use, Fire Weather Index (FWI) and wind direction. The model was tested on four recent wildfire events in Mediterranean landscapes.Key results The simulations reproduced observed wildfire scar shapes with good fidelity, capturing both interior and boundary complexity. The model dynamically responds to spatial variations in environmental conditions and is adaptable to different geographic contexts.Conclusions Fractal geometry provides a viable alternative for simulating wildfire spread, offering a scale-sensitive and flexible modeling approach.Implications This method may support scenario-based wildfire risk assessments and fuel management planning, and could be extended for real-time forecasting with further development.

Our previous studies have shown that fire weather conditions in the Mediterranean and specifically over Greece are expected to become more severe with climate change, impling potential increases in burnt area. Here, we employ the Joint UK Land Environment Simulator (JULES) coupled with the INFERNO fire model driven by future climate projections from the UKESM1 model to investigate the repercussions of climate change and future vegetation changes on burnt area over Greece. We validate modelled burnt area against the satellite-derived GFED5 dataset, and find the model's performance to be good, especially for the more fire-prone parts of the country in the south Greece. For future simulations, we use future climate data following three Shared Socioeconomic Pathways (SSPs), consisting of an optimistic climate change scenario where fossil fuel emissions peak and decline beyond 2020 (SSP126), a middle-of-the-road scenario (SSP370), and a pessimistic scenario where emissions continue to rise throughout the century (SSP8.5). Our results show increased burnt area in the future compared to the present-day period in response to overall hotter and drier climatological conditions. We use an additional JULES-INFERNO simulation in which dynamic vegetation was activated, and find that it features smaller future burned area increases compared to our simulation with static present-day vegetation. For this dynamically changing vegetation simulation the greatest burnt area increases are found for southern Greece, due to higher future availability of flammable and heat-resistant needleleaf trees and the smallest decreases in agricultural areas of northern Greece due to a reduction in the aforementioned tree category.

Our previous studies have shown that climatic conditions in the Mediterranean and specifically over Greece are expected to change, resulting in an increase in fire season length which implies increases in burnt area. Our research employs the Joint UK Land Environment Simulator (JULES) to investigate the repercussions of climate change and future land use land cover (LULC) on future burnt area using UKESM1-0-LL gridded data from the ISIMIP3b model run. In the present study, the modelled burnt area is validated against satellite observations from Copernicus. We use two representative concentration pathways (RCPs) consisting of an optimistic emissions scenario where emissions peak and decline beyond 2020 (RCP2.6) and a pessimistic scenario, in terms of mitigation where emissions continue to rise throughout the century (RCP8.5). Our results show increased burnt area in the distant future compared to the present period in response to higher future availability of heat resistant needle leaf trees.

Wildfires are significant contributors to atmospheric gases and aerosols, impacting air quality and composition. This pollution from fires also affects radiative forcing, influencing short-term weather patterns and climate dynamics. Our research employs the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) to investigate the repercussions of wildfires on aerosol abundances and associated immediate weather responses. We examine the summer season of 2021, a period marked by severe wildfire events in the country during a heatwave period. We conducted sensitivity experiments including and excluding wildfire emissions to measure their effects on aerosol optical depth (AOD), radiative forcing, and weather features such as temperature, humidity, clouds, and atmospheric circulation. Our findings demonstrate that the radiative impacts of wildfires negatively influence the local temperature over the fire smoke plume-affected areas. Conversely, neighbouring areas of continental Greece experience increases in temperature due to remote effects of wildfire emissions, caused by meteorological feedbacks that reduce atmospheric humidity. Crucially, including fire emissions significantly improves the simulated surface temperatures predicted by the model over the Greek domain. Our work demonstrates that wildfire-generated aerosols can significantly impact weather conditions and highlights the importance of including both local radiative effects and remote feedback for achieving more accurate weather prediction.

Wildfires stand as significant contributors to atmospheric aerosols, exerting a substantial influence on air quality and radiative forcing. In our research, we utilized the Weather Research and Forecasting model coupled with chemistry (WRF−Chem) to delve into the repercussions of wildfires on aerosol pollution and meteorological interactions. Our study centered on Greece, serving as a poignant test case. We focus on the summer of 2021, a period marked by intense wildfire occurrences within the nation.

Wildfires are a major source of atmospheric gases and aerosols, and can have significant impacts on atmospheric composition and air quality. Simultaneously, fire-generated pollution exerts radiative forcing and can therefore influence short-term weather and climate. In our work, we have utilized the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) to study the impact of wildfires on aerosol pollution and associated short-term meteorological feedbacks, focusing on the geographical area of Greece as a test case. We examine the summer season of 2021, during which intense wildfire activity occurred in the country during a heatwave period. We conducted sensitivity experiments with and without emissions from fires to quantify the impact of such emissions on surface particulate matter levels (focusing on PM2.5), aerosol optical depth (AOD), radiative forcing, and weather features such as temperature, humidity, clouds and atmospheric circulation. Our findings demonstrate that the impact of wildfires on AOD influences the local temperature over the fire affected areas negatively. Conversely, neighbouring areas of continental Greece experience increases in temperature when fire emissions are included in the simulation, due to meteorological feedbacks that reduce atmospheric humidity. Our work demonstrates that wildfire-generated aerosols can significantly impact weather conditions, and highlights the importance of including such feedbacks to achieve more accurate weather prediction.

Wildfires are a major source of atmospheric aerosols and can have significant impacts on air quality and radiative forcing. In our work, we have utilized the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) to study the impact of wildfires on aerosol pollution and meteorological feedbacks, focusing on the geographical area of Greece as a test case. We focus on the summer season of 2021, during which intense wildfire activity occurred in the country. We have performed sensitivity experiments with and without emissions from fires as a way to quantify the impact of such emissions on atmospheric pollutants, AOD, radiative forcing and weather variables (temperature, humidity, winds). Our results show that wildfires can have a significant impact on AOD, with the magnitude of the effect depending on the size and intensity of the wildfire and the meteorological conditions. Our recent work has shown that fire prone areas determined using the FWI index seem to link closely with the areas in Greece with the highest burnt area. Since the emitted aerosols are an important parameter, we test how well the emissions correlate to the FWI. Overall, our work demonstrates the potential role of wildfires in the evolution of short-term weather conditions via fire pollution radiative forcing, and provides new insights into the mechanisms leading to such effects.

The increased frequency and severity of wildfires in the Mediterranean region generates significant damages in ecosystems and landscapes while harming human populations. Institutional complexities, along with socioeconomic and demographic changes encouraging development into the wildland-urban interface, rural abandonment, and focus on fire suppression, are increasing the vulnerability and flammability of Mediterranean ecosystems. Developing effective strategies for managing wildfire incidence and its aftermath requires understanding of the public preferences for wildfire policy characteristics. Here we elicit public preferences for wildfire mitigation policies employing a stated choice experiment applied in Crete, Greece. A region with typical Mediterranean landscape experiencing significant development and rural-to-urban migration that disrupts existing fire regimes. We estimate conditional logit, mixed logit and latent class models to study the general public's preferences and willingness to pay for limiting wildfire frequency and agricultural land burnt, maintaining landscape features, and managing post-wildfire recovery. Results of our study show that measures to manage post-wildfire damage are consistently valued as the most positive amongst the sampled respondents, achieving values that range between €25.92 in conditional logit model to €46 in one of the latent classes identified. Improving the landscape quality follows in importance, although it shows more heterogeneity in the responses. The latent class approach allowed to identify that those associated with either the agricultural or the tourism sector of the sampled individuals, displayed significantly different preferences for the proposed attributes. Overall, our findings indicate that there is a strong preference amongst the general public to shift current policies based on suppression towards more integrated approaches dealing both with prevention and post-fire management. The outcomes of this study serve to guide decision makers on targeted management plans based on their audience.

Fire regimes form an integral part of terrestrial biomes in the Mediterranean region as they provide essential disturbances which change the structure and function of plants that favour Mediterranean type climates. Fire is inextricably linked to such ecosystems and cannot be excluded from them. However, the intensification of human activities in Greece, coupled with increasingly unpredictable wildfires has created huge imbalances and jeopardised the ecological integrity of ecosystems. Expansions into the wildland urban interface, rural abandonment, and the focus on fire suppression are increasing the vulnerability and flammability of the Greek environment. The duality of fire is delicate, both at local and national level, catastrophic wildfires singe deeply on landscapes and economies, social burns can take just as long to heal. In Greece, this is further exacerbated by the burgeoning socio-economic and political complexities that have catalysed the current ineffective and unsustainable fire management strategies. Damages from wildfires affect ecosystem services which can lead to a reduction in human wellbeing. Understanding the interactions between ecosystems and humans through environmental valuation is key to implementing effective policy. This study uses economic valuation methods in the form of a choice experiment to elicit public preference for a wildfire management policy in Crete. A survey was deployed around the island, with respondents asked about their preferences between different management strategies. The policies outlined in the survey are made up of the following attributes: risk of fire, agricultural production, landscape quality and post-wildfire damage mitigation. Results from this study indicate a positive preference by the public for a new proposed policy. The findings from this study can be used for decision making in Crete and other similar southern European environments by providing metrics for appropriate wildfire management.

Recent studies have shown that temperature and precipitation in the Mediterranean are expected to change, contributing to longer and more intense summer droughts that even extend out of season. In connection to this, the frequency of forest fire occurrence and intensity will likely increase. In the present study, the changes in future fire danger conditions are assessed for the different regions of Greece using the Canadian fire weather index (FWI). Gridded future climate output as estimated from three regional climate models from the Coordinated Regional Downscaling Experiment are utilized. We use three representative concentration pathways (RCPs) consisting of an optimistic emissions scenario where emissions peak and decline beyond 2020 (RCP2.6), a middle-of-the-road scenario (RCP4.5) and a pessimistic scenario, in terms of mitigation where emissions continue to rise throughout the century (RCP8.5). Based on established critical fire FWI threshold values for Greece, the future change in days with critical fire danger were calculated for different areas of Greece domains. The results show that fire danger is expected to progressively increase in the future especially in the high-end climate change scenario with southern and eastern regions of Greece expected to have up to 40 additional days of high fire danger relative to the late 20th century, on average. Crete, the Aegean Islands, the Attica region, as well as parts of Peloponnese are predicted to experience a stronger increase in fire danger.

<p>Wildfires are integral parts of ecosystems but at the same time they consist a threat for manmade and natural environments. Variability in the area burned by wildfires has been largely attributed to weather and climate drivers, hence fire danger indices such as the Canadian Fire Weather Index (FWI) uses solely climate variables. The FWI uses four climate variables (precipitation, temperature, wind and relative humidity), to estimate two sub-indices, one for the wildfire initial spread danger - the initial spread index, and one that accounts for the longer-term drought effects on the fire danger - the buildup index, from which the FWI is finally assessed. Here, we establish correlations between the individual climate variables, FWI and its subindices, with observed GFED monthly burned area, for each one of the 14 GFED pyrographic region, at a global scale. The correlations are established on aggregated by the size of burned area data, to reduce the effect of other smaller scale climate effects, as well as other socioeconomic factors such as fire suppression activities, etc. The established correlations are then used to estimate the relative sensitivity of the area burned, to each climate variable and FWI component. The analysis is repeated for different burned area land use types, i.e. forest areas, non-forest areas as well as their combination. Our results indicate the relative importance of the four climate variables, as well as the two sub-indices of FWI index, for each GFED region. The results highlight the significance of temperature and relative humidity to the variability of area burned, in many regions, globally. This work contributes to a better understanding of the climate drivers of global wildfire activity.</p><p> </p><p>This work is supported by CLIMPACT - National Research Network on Climate Change and its Impacts project, financed by the Public Investment Program of Greece and supervised by General Secretariat for Research and Technology (GSRT); and by the Leverhulme Centre for Wildfires, Environment, and Society through the Leverhulme Trust, grant number RC-2018-023.</p>

Wildfire is an integral part of the Earth system, but at the same time it can pose serious threats to human society and to certain types of terrestrial ecosystems. Meteorological conditions are a key driver of wildfire activity and extent, which led to the emergence of the use of fire danger indices that depend solely on weather conditions. The Canadian Fire Weather Index (FWI) is a widely used fire danger index of this kind. Here, we evaluate how well the FWI, its components, and the climate variables from which it is derived, correlate with observation-based burned area (BA) for a variety of world regions. We use a novel technique, according to which monthly BA are grouped by size for each Global Fire Emissions Database (GFED) pyrographic region. We find strong correlations of BA anomalies with the FWI anomalies, as well as with the underlying deviations from their climatologies for the four climate variables from which FWI is estimated, namely, temperature, relative humidity, precipitation, and wind. We quantify the relative sensitivity of the observed BA to each of the four climate variables, finding that this relationship strongly depends on the pyrographic region and land type. Our results indicate that the BA anomalies strongly correlate with FWI anomalies at a GFED region scale, compared to the strength of the correlation with individual climate variables. Additionally, among the individual climate variables that comprise the FWI, relative humidity and temperature are the most influential factors that affect the observed BA. Our results support the use of the composite fire danger index FWI, as well as its sub-indices, the Build-Up Index (BUI) and the Initial Spread Index (ISI), comparing to single climate variables, since they are found to correlate better with the observed forest or non-forest BA, for the most regions across the globe.

The Canadian Fire Weather Index (FWI) is a meteorologically based index designed initially to be used in Canada but it can also be used worldwide, including the Mediterranean, to estimate fire danger in a generalized fuel type based solely on weather observations. The four weather variables are measured and used as inputs to the FWI (rain accumulated over 24 h, temperature, relative humidity, and wind speed) are generally taken daily at noon local standard time. Recent studies have shown that temperature and precipitation in the Mediterranean, and more specifically in Greece are expected to change, indicating longer and more intense summer droughts that even extend out of season. In connection to this, the frequency of forest fire occurrence and intensity is on the rise. In the present study, the FWI index is used in order to assess changes in future fire danger conditions. To represent meteorological conditions, regional EURO-CORDEX climate model simulations over the Mediterranean and mainly Greece at a spatial resolution of 11 km, were utilized. In order to assess the impact of future climate change, we used two Representative Concentration Pathway (RCP) scenarios consisting of an optimistic emission scenario where emissions peak and decline beyond 2020 (RCP2.6) and a pessimistic scenario where emissions continue to rise throughout the century (RCP8.5). We compare the FWI projections for two future time periods, 2021-2050 and 2071-2100 with reference to the historical time period 1971-2000. Based on the critical fire risk threshold values that have been established in previous studies for the area of Greece, the days with critical fire risk were calculated for different Greek domains.