title: Global carbon dioxide emissions from inland waters.
abstract: Carbon dioxide (CO2) transfer from inland waters to the atmosphere, known as CO2 evasion, is a component of the global carbon cycle. Global estimates of CO2 evasion have been hampered, however, by the lack of a framework for estimating the inland water surface area and gas transfer velocity and by the absence of a global CO2 database. Here we report regional variations in global inland water surface area, dissolved CO2 and gas transfer velocity. We obtain global CO2 evasion rates of 1.8(+0.25)(-0.25)  petagrams of carbon (Pg C) per year from streams and rivers and 0.32(+0.52)(-0.26)  Pg C yr(-1) from lakes and reservoirs, where the upper and lower limits are respectively the 5th and 95th confidence interval percentiles. The resulting global evasion rate of 2.1 Pg C yr(-1) is higher than previous estimates owing to a larger stream and river evasion rate. Our analysis predicts global hotspots in stream and river evasion, with about 70 per cent of the flux occurring over just 20 per cent of the land surface. The source of inland water CO2 is still not known with certainty and new studies are needed to research the mechanisms controlling CO2 evasion globally.
authors.affiliation: Yale School of Forestry and Environmental Studies, 195 Prospect Street, New Haven, Connecticut 06511, USA.
authors.forename: Peter A
authors.initials: PA
authors.lastname: Raymond
authors.forename: Jens
authors.initials: J
authors.lastname: Hartmann
authors.forename: Ronny
authors.initials: R
authors.lastname: Lauerwald
authors.forename: Sebastian
authors.initials: S
authors.lastname: Sobek
authors.forename: Cory
authors.initials: C
authors.lastname: McDonald
authors.forename: Mark
authors.initials: M
authors.lastname: Hoover
authors.forename: David
authors.initials: D
authors.lastname: Butman
authors.forename: Robert
authors.initials: R
authors.lastname: Striegl
authors.forename: Emilio
authors.initials: E
authors.lastname: Mayorga
authors.forename: Christoph
authors.initials: C
authors.lastname: Humborg
authors.forename: Pirkko
authors.initials: P
authors.lastname: Kortelainen
authors.forename: Hans
authors.initials: H
authors.lastname: Dürr
authors.forename: Michel
authors.initials: M
authors.lastname: Meybeck
authors.forename: Philippe
authors.initials: P
authors.lastname: Ciais
authors.forename: Peter
authors.initials: P
authors.lastname: Guth
mesh_terms: D001272:Atmosphere / Q000737:chemistry; D057486:Carbon Cycle; D002245:Carbon Dioxide / Q000032:analysis*; D005618:Fresh Water / Q000737:chemistry*; D005740:Gases / Q000032:analysis; D005843:Geography; D038622:Internationality; D045483:Rivers / Q000737:chemistry
chemical_list: D005740:Gases; D002245:Carbon Dioxide