Pathways to sustainable land futures in Brazil: biodiversity, carbon, water, and local climate impacts

The future of the Brazilian biomes is crucial to achieving local, national, and global sustainability.This study presents the first set of qualitative and quantitative target-seeking environmental scenarios for Brazil as a whole, representing contrasting perspectives on pathways to sustainability: the Green Transition scenario (GreenTS) and the Lives in Balance scenario (LivesBS), compared with a current trends scenario (CurrentTS).The GreenTS emphasizes technological solutions and efficiency gains, while LivesBS prioritizes plural ways of living and producing in symbiosis with nature.Specific solutions and political choices differentiate the sustainability pathways, including the adoption of fast-growing planted forests for carbon capture, the protection and recovery of forest and non-forest vegetation, a focus on croplands and monocultures, or on a more diversified, less uniform, and unequal land structure.Each pathway's underlying choices drive divergent land-use projections for 2050, affecting various environmental indicators.Large-scale native forest recovery under both sustainable pathways contributes to a net-negative CO2 balance at the national level, of the same magnitude as the positive balance in CurrentTS, with marked differences across biomes.On the other hand, the protection of non-forest vegetation and more diversified land uses in LivesBS contribute to higher Mean species abundance across all biomes.Water pollution risk is significantly lower in both sustainable pathways, but a smaller cropland area further reduces it in LivesBS.Agricultural areas in the Amazon and Cerrado are projected to experience greater average rainfall reductions under CurrentTS (-38.6 mm/yr and -37.8 mm/yr, respectively).Both sustainable pathways reduce rainfall by a similar amount in the Amazon, but LivesBS outperforms GreenTS in the Cerrado, owing to the protection and recovery of non-forest vegetation.Beyond the threats posed by current trends, our results highlight the need to critically evaluate the multidimensional impacts of alternative sustainability-oriented solutions in order to inform decisions aimed at achieving sustainability goals.