Global CO2 emission from volcanic lakes

Abstract

The global CO2 discharge from subaerial volcanism has been estimated at ~300 Mt yr–1. However, estimates of CO2 emissions from volcanic lakes have not been considered. In order to improve this information, extensive research on CO2 emissions of volcanic lakes worldwide has been performed. The observed normalized average CO2 emission rates increase from alkaline (5.5 t km–2 d–1), to neutral (201.2 t km–2 d–1), to acid (614.2 t km–2 d–1) in volcanic lakes. Taking into account (1) normalized CO2 emission rates, (2) the number of volcanic lakes in the world (~769), and (3) the fraction and average areas of the investigated alkaline, neutral, and acid volcanic lakes, the estimated global CO2 emission from volcanic lakes is 117 ± 19 Mt yr–1, with 94 ± 17 Mt yr–1 as deep-seated CO2 . This study highlights the importance of a revision of the actual global CO2 discharge from subaerial volcanism.