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Constraining the carbon tetrachloride (CCl 4 ) budget using its global trend and inter‐hemispheric gradient
Author(s) -
Liang Qing,
Newman Paul A.,
Daniel John S.,
Reimann Stefan,
Hall Bradley D.,
Dutton Geoff,
Kuijpers Lambert J. M.
Publication year - 2014
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2014gl060754
Subject(s) - greenhouse gas , troposphere , stratosphere , environmental science , montreal protocol , atmospheric sciences , ozone , atmosphere (unit) , carbon tetrachloride , ozone depletion , tropospheric ozone , climatology , ozone layer , chemistry , meteorology , physics , geology , oceanography , organic chemistry
Abstract Carbon tetrachloride (CCl 4 ) is a major anthropogenic ozone‐depleting substance and greenhouse gas and has been regulated under the Montreal Protocol. However, the near‐zero 2007–2012 emissions estimate based on the UNEP reported production and feedstock usage cannot be reconciled with the observed slow decline of atmospheric concentrations and the inter‐hemispheric gradient (IHG) for CCl 4 . Our 3‐D model simulations suggest that the observed IHG (1.5 ± 0.2 ppt for 2000–2012) is primarily caused by ongoing current emissions, while ocean and soil losses and stratosphere‐troposphere exchange together contribute a small negative gradient (~0 – −0.3 ppt). Using the observed CCl 4 global trend and IHG, we deduce that the mean global emissions for the 2000–2012 period are 39 34 45 Gg/yr (~30% of the peak 1980s emissions) and a corresponding total lifetime of 35 37 32 years.