fires

Afforestation reduces fire occurrence in Colombia’s tropical savannas
Changes in land use, climate, and socio-ecology drive altered fire regimes that in turn reshape global ecosystems. Rapid afforestation with commercial tree plantations is transforming fire-prone savannas and grasslands globally and particularly in tropical South America, yet its effects on fire dynamics remain poorly understood. Using hierarchical models, we analysed trends in annual burned area within concentric buffers (1 to 6 km) around each of 44 plantation and 52 grassland sites in Colombia’s Orinoquia region—a savanna grassland forest mosaic undergoing major land-use transitions from the expansion of commercial tree plantations. Plantations reduced burned areas in two ways: order-of-magnitude increases in plantation area reduced burnt area by 15% and plantation sites reduced their burnt area by 2% each year; both results consistent with trees replacing more inflammable grassland vegetation. While the mechanisms behind divergent savanna/plantation fire dynamics remain unresolved and could involve active fuel management and fire response, increased canopy cover or some combination thereof, this study provides spatially explicit, context-sensitive evidence on how land-use transitions interact with fire regimes with direct relevance for grasslands and savanna management and climate adaptation policy in South America.
Weather disasters and their underreported transboundary impacts on Amazonian communities
In the Amazon, climate and land use change are expected to intensify risks from weather disasters, posing major challenges to people and ecosystems. Yet, how weather disasters already affect the peoples of Amazonia remains understudied. To quantify regional impacts, we compiled and analyzed reports on weather disaster category, frequency, human, and economic impacts from 2013 to 2023 across five Amazonian countries. We counted 12,541 disaster reports, affecting up to >3 million Amazonians and >100,000 pieces of public infrastructure in a single year. There were disproportionate concentrations of landslides in the Amazon-Andes of Ecuador, and fires associated with agricultural management and sometimes land grabbing in the Orinoco-Amazon ecotone of Colombia and along the southern Arc of Deforestation of Bolivia and Brazil. We argue that weather disaster impacts in the Amazon are underreported because: 1) data from four Amazonian countries could not be obtained, 2) cross-country reporting was not standardized and 3) it varied such that virtually all heatwave and most drought data came from Brazil, despite published evidence that both disaster types are present throughout the region. Disaster impacts are already significant, underscoring the need for transboundary policies on land use, local adaptation strategies for communities and infrastructure, and coordinated regional efforts to share and update weather disaster management plans. Developing consistent, accessible, and interoperable datasets across the region is fundamental to building a comprehensive understanding of weather-related disasters in the Amazon and to informing effective public policies that strengthen prevention, response, and adaptation efforts.. These findings and recommendations provide a basis for discussing regional climate hazards at CoP30 in Belém do Pará, Brazil, in November.