Flux measurements of nonvolcanic CO 2 emission from some vents in central Italy

In central Italy, nonvolcanic CO 2 is discharged from many areas of focused degassing (vents and associated strong diffuse emission) and from high‐pCO 2 groundwater. We estimate that there are at least 100 CO 2 vents in central Italy, many of which have a history of lethality to animals and humans. The gas vents are extremely efficient pathways for transporting large amounts of deeply derived CO 2 from gas reservoirs to the surface. As CO 2 fluxes from these vents were heretofore unmeasured, several complementary methods were developed to measure the CO 2 flux from seven of these vents, which cumulatively discharge 3.1×10 9 mol yr −1 CO 2 (472 t d −1 ). Considering all of the vents in central Italy, the total CO 2 flux from vents alone may be similar to the CO 2 emission from the Taupo Volcanic Zone in New Zealand (∼10 10 mol yr −1 ; ∼1200 t d −1 ) and other areas of high heat flow. Summing the CO 2 discharged from vents, areas of diffuse CO 2 degassing, and degassing of high‐pCO 2 groundwater, we provisionally estimate that the total nonvolcanic CO 2 flux to the atmosphere in central Italy may be >10 11 mol yr −1 (∼12,000 t d −1 ).