CO2 flux emissions from the Earth's most actively degassing volcanoes, 2005-2015

Alessandro Aiuppa , Tobias P. Fischer , Terry Plank , Philipson Bani (1, 2)

1 OPGC - Observatoire de Physique du Globe de Clermont-Ferrand
2 LMV - Laboratoire Magmas et Volcans

The global carbon dioxide (CO₂) flux from subaerial volcanoes remains poorly quantified, limiting our understanding of the deep carbon cycle during geologic time and in modern Earth. Past attempts to extrapolate the global volcanic CO₂ flux have been biased by observations being available for a relatively small number of accessible volcanoes. Here, we propose that the strong, but yet unmeasured, CO₂ emissions from several remote degassing volcanoes worldwide can be predicted using regional/global relationships between the CO₂/S_T ratio of volcanic gases and whole-rock trace element compositions (e.g., Ba/La). From these globally linked gas/rock compositions, we predict the CO₂/S_T gas ratio of 34 top-degassing remote volcanoes with no available gas measurements. By scaling to volcanic SO₂ fluxes from a global catalogue, we estimate a cumulative "unmeasured" CO₂ output of 11.4 ± 1.1 Mt/yr (or 0.26 ± 0.02.10¹² mol/yr). In combination with the measured CO₂ output of 27.4 ± 3.6 Mt/yr (or 0.62 ± 0.08.10¹² mol/yr), our results constrain the time-averaged (2005-2015) cumulative CO₂ flux from the Earth's 91 most actively degassing subaerial volcanoes at 38.7 ± 2.9 Mt/yr (or 0.88 ± 0.06.10¹² mol/yr).

Domaines: Planète et Univers [physics]; Volcanologie

Alessandro Aiuppa, Tobias P. Fischer, Terry Plank, Philipson Bani. CO2 flux emissions from the Earth's most actively degassing volcanoes, 2005-2015. Scientific Reports, 2019, 9, 289, p. 75-89. ⟨10.1038/s41598-019-41901-y⟩. ⟨insu-03708956⟩