The gathering firestorm in southern Amazonia

Abstract

Wildfires, exacerbated by extreme weather events and land use, threaten to change the Amazon from a net carbon sink to a net carbon source. Here, we develop and apply a coupled ecosystem-fire model to quantify how greenhouse gas-driven drying and warming would affect wildfires and associated CO 2 emissions in the southern Brazilian Amazon. Regional climate projections suggest that Amazon fire regimes will intensify under both low-and high-emission scenarios. Our results indicate that projected climatic changes will double the area burned by wildfires, affecting up to 16% of the region's forests by 2050. Although these fires could emit as much as 17.0 Pg of CO 2 equivalent to the atmosphere, avoiding new deforestation could cut total net fire emissions in half and help prevent fires from escaping into protected areas and indigenous lands. Aggressive efforts to eliminate ignition sources and suppress wildfires will be critical to conserve southern Amazon forests.

Implications of CMIP6 Projected Drying Trends for 21st Century Amazonian Drought Risk

“…The months of September-November mark the end of the dry season in southern Amazonia, and delays in the end of the dry season are associated with a prolonged fire season (Fu et al, 2013). Fire risk is associated with interactions among land use change and dry-air spells during the dry season (e.g., Brando et al, 2020;Morton et al, 2013), so future decreases in dry-season and end of dry-season rainfall ( Figure S1) and soil moisture ( Figure S2) along the forest edge in southern Amazonia could have consequences for southern Amazonia fire season.…”

When will the Amazon hit a tipping point?

“…This January, Brando and others published a paper suggesting that a warmer, drier climate could double the area of burnt forest in the southern Brazilian Amazon over the next three decades 8 . Their study indicates that, even without deforestation, climate change alone will inevitably cause a surge in the area burnt over the coming years.…”

Pathways to positive scenarios for the Amazon forest in Pará state, Brazil

“…Forest degradation is defined as a state of anthropogenically induced succession, where ecological processes that underlie forest dynamics are diminished (Ghazoul et al 2015). Among anthropogenic activities that cause degradation, fire and logging are significantly present in the Amazonian landscape and are extensively studied (Nepstad et al 1999, Gerwing 2002, Cochrane 2003, Aragão et al 2007, Silva Junior et al 2018, Brando et al 2020. Here, we considered forest degradation caused by fires and logging a direct driver of forest cover change.…”

“…Besides that, episodes of severe droughts (e.g. El Niño) tend to become more frequent over the years due to climate change, increasing tree mortality and, consequently, the vulnerability to fires (Nepstad et al 2007, Brando et al 2014, Brando et al 2020. Such processes, as forest degradation and climate change, set up a positive feedback, where degraded forests are increasingly under threat (Rosa et al 2013).…”