The Deep Earth Carbon Degassing (DECADE) project is an initiative to unite scientists around the world to make tangible advances towards quantifying the amount of carbon outgassed from the Earth's deep interior (core, mantle, crust) into the surface environment (e.g. biosphere, hydrosphere, cryosphere, atmosphere) through naturally occurring processes. DECADE is an initiative within the Deep Carbon Observatory (DCO).
Volcanoes are the main pathway in which deeply sourced volatiles, including carbon, are transferred from the Earth's interior to the surface environment.[1] An additional, though less well understood, pathway includes along faults and fractures within the Earth's crust,[2] often referred to as tectonic degassing. When the DCO was first formed in 2009 estimates of global carbon flux from volcanic regions ranged from 65 to 540 Mt/yr,[2] and constraints on global tectonic degassing were virtually unknown.[2] The order of magnitude uncertainty in current volcanic/tectonic carbon outgassing makes answering fundamental questions about the global carbon budget virtually impossible. In particular, one fundamental unknown is if carbon transferred to the Earth's interior via subduction is efficiently recycled back to the Earth's mantle lithosphere, crust and surface environment through volcanic and tectonic degassing, or if significant quantities of carbon are being subducted into the deep mantle.[3] Because significant quantities of mantle carbon are also released through mid-ocean ridge volcanism, if carbon inputs and outputs at subduction zone settings are in balance, then the net effect will be an imbalance in the global carbon budget, with carbon being preferentially removed from the Earth's deep interior and redistributed to more shallow reservoirs including the mantle lithosphere, crust, hydrosphere and atmosphere. The implications of this may mean that carbon concentrations in the surface environment are increasing over Earth's history, which has significant implications for climate change.
Findings from the DECADE project will increase our understanding of the way carbon cycles through deep Earth, and patterns in volcanic emissions data could potentially alert scientists to an impending eruption.[4]