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Aerial measurements using unoccupied aerial systems (UAS) transform our ability to measure and monitor volcanic plumes., Volcanic emissions are a critical pathway in Earth’s carbon cycle. Here, we show that aerial measurements of volcanic gases using unoccupied aerial systems (UAS) transform our ability to measure and monitor plumes remotely and to constrain global volatile fluxes from volcanoes. Combining multi-scale measurements from ground-based remote sensing, long-range aerial sampling, and satellites, we present comprehensive gas fluxes—3760 ± [600, 310] tons day−1 CO2 and 5150 ± [730, 340] tons day−1 SO2—for a strong yet previously uncharacterized volcanic emitter: Manam, Papua New Guinea. The CO2/ST ratio of 1.07 ± 0.06 suggests a modest slab sediment contribution to the sub-arc mantle. We find that aerial strategies reduce uncertainties associated with ground-based remote sensing of SO2 flux and enable near–real-time measurements of plume chemistry and carbon isotope composition. Our data emphasize the need to account for time averaging of temporal variability in volcanic gas emissions in global flux estimates.

Bagana, an andesite lava cone on Bougainville Island, Papua New Guinea, is\ud thought to be a very young central volcano. We have tested this idea by estimating\ud the volumes of lava extruded over different time intervals (1-, 2-, 3-, 9-, 15-, 70-\ud years) using digital elevation models (DEMs), mainly created from satellite data. Our\ud results show that the long-term extrusion rate at Bagana, measured over years to\ud decades, has remained at about 1.0 m3s-1. We present models of the total edifice\ud volume, and show that, if our measured extrusion rates are representative, the\ud volcano could have been built in only ~300 years. It could also possibly have been\ud built at a slower rate during a longer, earlier period of growth. Six kilometres NNW of\ud Bagana, an andesite-dacite volcano, Billy Mitchell, had a large, caldera-forming\ud plinian eruption 437 years ago. We consider the possibility that, as a result of this\ud eruption, the magma supply was diverted from Billy Mitchell to Bagana. It seems that\ud Bagana is a rare example of a very youthful, polygenetic, andesite volcano. The\ud characteristics of such a volcano, based on the example of Bagana, are: a\ud preponderance of lava products over pyroclastic products, a high rate of lava\ud extrusion maintained for decades, a very high rate of SO2 emission, evidence of\ud magma batch fractionation and location in a trans-tensional setting at the end of an\ud arc segment above a very steeply dipping and rapidly converging subduction zone