evidence: Volcanoes are the main pathway to the surface for volatiles that are stored within the Earth. Carbon dioxide (CO2) is of particular interest because of its potential for climate forcing. Understanding the balance of CO2 that is transferred from the Earth’s surface to the Earth’s interior, hinges on accurate quantification of the long-term emissions of volcanic CO2 to the atmosphere. Here we present an updated evaluation of the world’s volcanic CO2 emissions that takes advantage of recent improvements in satellite-based monitoring of sulfur dioxide, the establishment of ground-based networks for semi-continuous CO2-SO2 gas sensing and a new approach to estimate key volcanic gas parameters based on magma compositions. Our results reveal a global volcanic CO2 flux of 51.3 ± 5.7 Tg CO2/y (11.7 × 1011 mol CO2/y) for non-eruptive degassing and 1.8 ± 0.9 Tg/y for eruptive degassing during the period from 2005 to 2015. [...] Volcanism is the main pathway for the transfer of carbon and other volatiles stored in the deep Earth to the surface1,2. Volcanic carbon dioxide (CO2) is a key non-anthropogenic regulator of atmospheric CO2 levels and has, over geologic time scales, affected the evolution of Earth’s climate3,4,5. Quantifying the volcanic CO2 flux is an ongoing challenge for the volcano science community and was the primary driver for launching the Deep Earth Carbon Degassing (DCO-DECADE) initiative of the Deep Carbon Observatory. DCO-DECADE was first established in 2011 during IAVCEI Commission of the Chemistry of Volcanic Gases workshop in Kamchatka and has since provided unprecedented global coverage of volcanic gas emission and composition measurements through continuous monitoring and campaign efforts (https://en.wikipedia.org/wiki/Deep_Earth_Carbon_Degassing_Project).