Climate Change, Aerosols Drive Persistent Southwest US Drought

Recent studies reveal that the persistent drought in the American Southwest is primarily driven by human-induced climate change and air pollution, which have reduced precipitation and altered atmospheric circulation patterns since around 1980. This decline is linked to La Niña-like cooling trends in the tropical Pacific and a warming trend in the North Pacific, which together create circulation patterns that prevent increased rainfall even under El Niño-like conditions. Researchers found that these factors have caused the fastest soil drying in the region's history and made drought conditions inevitable as the planet continues to warm. Innovative climate models incorporating satellite data and paleoclimate reconstructions further confirm that moderate hemispheric warming excites Pacific Decadal Oscillation-like states, suppressing precipitation and deepening drought severity. This complex interaction of ocean-atmosphere dynamics and aerosols underscores the challenges for water resource management and ecosystem preservation in the Southwest. Overall, the drought is not a temporary weather anomaly but a long-term climate trend exacerbated by human activity.