Changes in the aridity index across Brazilian biomes

Area of Science:

• Environmental Science
• Climate Science
• Geography

Background:

• Global aridity has increased in recent decades.
• Aridification trends are a growing concern worldwide.
• Understanding regional changes is crucial for adaptation.

Purpose of the Study:

• To analyze spatial and temporal changes in aridity in Brazil from 1961-2020.
• To assess aridity trends across Brazil's main biomes.
• To identify areas vulnerable to desertification and vegetation stress.

Main Methods:

• Utilized the aridity index recommended by the desertification convention.
• Applied the index to a high-resolution observational gridded dataset.
• Analyzed changes in spatial distribution and biome-specific trends.

Main Results:

• Drier conditions observed in central and northeastern Brazil; wetter in the south.
• Expansion of semi-arid areas at the expense of dry subhumid and humid regions.
• Intensified aridification from 1991-2020, with new arid and dry subhumid areas detected.
• Negative trends in vegetation health index (VHI) across all biomes.

Conclusions:

• Observed aridification trends are consistent with future climate change projections.
• Increasing aridity and vegetation stress pose significant risks to Brazil's economy, agriculture, and water resources.
• Prioritization of soil and vegetation recovery actions is recommended for vulnerable regions.