Global biogenic isoprene emissions modulated by intensifying warm temperature extremes

Biogenic isoprene, the most abundant non-methane volatile organic compound, plays a critical role in air quality and climate. While its emissions are known to be temperature-dependent, the specific causal link to the intensification of warm temperature extremes observed in recent decades remains understudied. This study provides causal evidence connecting the rising intensity of warm temperature extremes to trends in biogenic isoprene emissions from 2000 to 2019. We integrated high-resolution CAMS-GLOB-BIOv3.1 emission data with ERA5 reanalysis products and applied the Information Flow (IF) framework to quantify the causal influence of extreme temperature on isoprene emission trends. Our results reveal a significant increase in isoprene emissions (>1.2 Tg yr -1 ) in tropical hotspots, which were significantly correlated with the intensity of extreme temperature (r > 0.8, p < 0.05). Importantly, causal analysis quantified a persistent, unidirectional IF from extreme temperatures to isoprene emissions, while the reverse pathway was negligible. This establishes extreme temperature as among the drivers of rising biogenic isoprene emissions, revealing a critical positive climate feedback loop under warming climate extremes. These findings highlight the need to incorporate extreme temperature–driven biogenic isoprene emission feedbacks into climate and air quality models to improve atmospheric composition and inform effective mitigation strategies for public health and climate stability. • First causal evidence: extreme heat drives global isoprene emissions (2000–2019). • Tropical hotspots exhibit the strongest isoprene rise associated with temperature extremes. • Unidirectional causality from heat to isoprene confirms climate-biosphere feedback. • Rising isoprene levels worsen air quality through the formation of ozone and secondary organic aerosols. • Urgent need to include temp-sensitive BVOCs in climate and air quality models.