Satellite‐derived isoprene emissions trace the spatiotemporal evolution of the 2015-2016 El Niño across terrestrial ecosystems

The El Niño event exerts a profound influence on the global carbon cycle by perturbing terrestrial photosynthesis through environmental stress. Plant isoprene emissions respond rapidly to such environmental stress, yet it remains unclear whether isoprene can capture the spatiotemporal evolution of El Niño. Here, we used satellite-derived global isoprene emissions for the first time to assess their dynamical response to the 2015–2016 El Niño. We observed that isoprene emissions increase by up to ~30% relative to the climatological mean, with pronounced anomalies emerging across tropical ecosystems. The spatiotemporal evolution of these anomalies closely aligns with the El Niño progression, as indicated by sea surface temperature anomalies in the equatorial Pacific. In contrast, commonly used satellite vegetation products, including leaf area index (LAI) and solar-induced chlorophyll fluorescence (SIF), exhibit weaker and spatially incoherent responses. These results demonstrate that satellite-derived isoprene provides a sensitive and mechanistically grounded tracer of ecosystem stress, offering a complementary perspective for monitoring the impacts and propagation of extreme climate events on terrestrial ecosystems.