Measuring and Modelling Tectonic CO2 Emissions Through Time

Geological processes governed paleo-atmospheric CO2 variations and exerted major control on past climate change beyond the million-year time scale. Vast deep carbon reservoirs are known to be activated at continental rifts, where the faulted lithosphere provides CO2 pathways and where recent surveys detected massive CO2 emissions. However, progress in quantifying natural CO2 degassing and its impact on past climate is impeded for 3 reasons: (1) current CO2 flux measurement techniques require labourintensive field surveys that can cover only small areas; (2) a consistent framework uniting geodynamic processes and CO2 transport to the surface is missing; (3) past CO2 flux from rifts is difficult to quantify because compilations do not account for geodynamic characteristics.EMERGE will enter uncharted territory by linking 3 innovative approaches. The project will: (1) advance airborne CO2 flux measurements via drones. Focusing on rifts in Kenya, Ethiopia, Czech Republic and Iceland, we will measure for the first time tectonic CO2 flux distributions of entire regions allowing unprecedented insight into subsurface CO2 pathways; (2) characterise geodynamic controls on lithospheric CO2 transport via novel numerical modelling techniques; and (3) integrate data of all known rifts since 540 million years ago to understand the role of tectonic degassing in shaping Earth’s climate through time.Zooming in on the geosphere-atmosphere interface, this project integrates interdisciplinary ideas and methods from geodynamics, micrometeorology, petrology, and paleoclimatology. EMERGE may generate broad impact on scientific and societal level: dronebased CO2 flux measurements will be a game changer in understanding tectonic CO2 release at rifts and other plate boundaries worldwide. The methodological and scientific advances may be essential for establishing a solid baseline of tectonic CO2 emissions to accurately quantify controls on past and future climate change.