Biophysic and socioeconomic drivers of burned area and carbon emissions from fires in the Pantropical tropical dry forests

The global burned area declined by nearly one-quarter between 1998 and
2015. Drylands contain a large proportion of these global fires but there
are important differences within the drylands, e.g., savannas and tropical
dry forests (TDF). Savannas, a biome fire-prone and fire-adapted, have
reduced the burned area, while the fire in the TDF is one of the most
critical factors impacting biodiversity and carbon emissions. Moreover,
under climate change scenarios TDF is expected to increase its current
extent and raise the risk of fires. Despite regional and global scale
effects, and the influence of this ecosystem on the global carbon cycle,
little effort has been dedicated to studying the influence of climate
(seasonality and extreme events) and socioeconomic conditions of fire
regimen in TDF. Here we use the Global Fire Emissions Database and,
climate and socioeconomic metrics to better understand long-term factors
explaining the variation in burned area and biomass in TDF at the
Pantropical scale. On average, fires affected 1.4% of the total TDF’ area
(60,208 km2) and burned 24.4% (259.6 Tg) of the global burned biomass
annually at Pantropical scales. Climate modulators largely influence local
and regional fire regimes. Inter-annual variation in fire regime is shaped
by El Niño and La Niña. During El Niño and the forthcoming year of La
Niña, there is an increment in extension (35.2 and 10.3%) and carbon
emissions (42.9 and 10.6%). Socioeconomic indicators such as land
management and population were modulators of the size of both, burned area
and carbon emissions. Moreover, fires may reduce the capability to reach
the target of “half protected species” in the globe, i.e., high-severity
fires are recorded in ecoregions classified as nature could reach half
protected. These observations may contribute to improving fire management.