Reacción a "The global population exposed to fires has increased by 40% in twenty years"

The article presents high-quality work carried out by renowned authors in the field of large-scale fire analysis. The study uses global fire and population density data with moderate spatial resolution, which is common in this type of global approach. The research question is relevant, as it seeks to demonstrate how the population's exposure to fires evolves and is spatially distributed. Although there are previous studies on the relationship between burned area and population, the approach is novel in that it focuses on fire exposure and differentiates between the role played by population dynamics on the one hand and changes in fires on the other in the evolution of this exposure between 2002 and 2021. Overall, the article offers robust and well-founded results, considering the limitations inherent in the use of moderate spatial resolution data. 

When it comes to global fire analysis, Africa is the main determinant of what happens, as it is the largest contributor to the area burned worldwide (around 70%).  In this case, the results show that population exposure to fires is increasing globally, driven mainly by changes in Africa (39.6%), where population dynamics (rather than burned area) explain this pattern. Less robust increases in exposure are also observed in South America and North America, in line with previous studies indicating an expansion of urban-forest interfaces in the US. In contrast, no increases in exposure are detected in Europe and Oceania.  

The main novelty of the study lies in demonstrating that there is a global increase in fire exposure and that this increase is mainly due to population growth and redistribution in fire-prone areas. This conclusion has important implications: the risk associated with fires could be increasing even when fire activity is not. If this increase in exposure is associated with an increase in fire-related impacts, this would reinforce the need for preventive measures, primarily landscape management.

The authors themselves acknowledge several limitations of their study. First, they only count the population within the perimeter of the fire as exposed, although the impacts may extend to people nearby or even at great distances (e.g., due to smoke). In addition, it should be noted that the level of impact is not the same for all burned areas. To partially address this issue, the authors include an analysis of more intense fires. This approach also has limitations associated with the spatial and temporal resolution of the data.  

Looking ahead, the availability of higher-resolution burned area and severity products (e.g., from the Sentinel-2 satellite) will allow for more accurate estimates of population exposure to fire, especially in regions with small fires or complex fire behavior. Likewise, incorporating more specific metrics, such as damage to homes or pollutant concentration in smoke, could offer a more practical view of whether the impacts of fires on the population are increasing".