JENS MUHLE
Academic (Project Scientist)
Geosciences Research Division
AGAGE global network
AGAGE measures all important greenhouse gases (GHGs) and ozone depleting substances (ODSs) in the global atmosphere
AGAGE measures synthetic greenhouse gases (GHGs) and ozone depleting substances (ODSs) at 13+ sites around the world. Measurement sites are operated by SIO and many international partners. The central AGAGE experimental and calibration laboratory is located at Scripps Institution of Oceanography at the University of California, San Diego.
Climate impact (radiative forcing) from greenhouse gases (GHGs)
Combined radiative forcing (RF, impact on the climate) of all GHGs is dominated by carbon dioxide (CO2), followed by methane (CH4), the sum of all ozone depleting substances (ODSs), nitrous oxide (N2O), and the sum of all synthetic GHGs. RF from HFCs is growing fast. Several ODSs are also strong GHGs, foremost the chlorofluorocarbons (CFCs).
CO2 (carbon dioxide), CH4 (methane), ODSs (ozone depleting substances), N2O (nitrous oxide), CFCs (chlorofluorocarbons), HCFCs (hydrochlorofluorocarbons), solvents (chlorinated solvents and feedstock compounds), halons (brominated fire fighting compounds), PFCs (perfluorocarbons), HFCs (hydrofluorocarbons), SF6 (sulfur hexafluoride), SO2F2 (sulfuryl fluoride), NF3 (nitrogen trifluoride). This and the following three plots were produced by CSIRO, one of our many international partners.
Chlorine and bromine from ozone depleting substances (ODSs)
Equivalent chlorine is a measure of how much chlorine and bromine is contained in halogenated compounds present in the troposphere (lower atmosphere). Many of these compounds are man-made and are emitted into the troposphere due to industrial activities. ECl is based on the abundances of all halogenated ODSs measured by AGAGE.
Equivalent effective stratospheric chlorine (EESC) is a measure of how much chlorine and bromine is available for ozone depletion in the stratosphere, originating from the ODSs in the troposphere.
Due to the phase-out of production and consumption of Ozone Depleting Substances (ODSs) mandated by the Montreal Protocol (on Substances that Deplete the Ozone Layer), EESC is slowly decreasing. This will eventually allow the ozone layer to recover and prevent the annual Antarctic "ozone hole" from opening.
The process is slow and needs to be monitored to detect new emissions of ODSs, which would threaten this recovery.
AGAGE global measurements of CFCs
Measurement data for these and other GHGs and ODSs can be found here (data portal).
CFCs have contributed to the annual Antarctic "ozone hole". Therefore, production and consumption of CFCs has been phased-out by the Montreal Protocol on Substances that Deplete the Ozone Layer to reduce the size of annual Antarctic "ozone hole" and to allow the ozone layer to eventually recover. Large "banks" of CFCs still exist, for example in old refrigerators and insulation foams where CFCs were used.
AGAGE global measurements of chlorinated species
Measurement data for these and other GHGs and ODSs can be found here (data portal).
Production and consumption of CH3CCl3 and CCl4 has been phased-out by the Montreal Protocol on Substances that Deplete the Ozone Layer to reduce the size of annual Antarctic "ozone hole" and to allow the ozone layer to eventually recover. CH3CCl3 has been a real success, but many sources of CCl4 emissions still exist as evident from a slower than expected atmospheric decline.
The other compounds are not regulated by the Montreal Protocol due to their short atmospheric lifetime or predominantly natural original. However, CHCl3 and CH2Cl2 are on the rise due to industrial activities.
Note, PCE data is reported on a calibration scale adopted from the National Oceanographic and Atmospheric Administration ( NOAA HATS).
AGAGE global measurements of halons and methyl bromide
Measurement data for these and other GHGs and ODSs can be found here (data portal).
Production and consumption of the halons and use of methyl bromide as fumigant are regulated by the Montreal Protocol on Substances that Deplete the Ozone Layer to reduce the size of annual Antarctic "ozone hole" and to allow the ozone layer to eventually recover. The halons have been and are still being used as fire fighting compounds. Large "banks" of them still exist in fire fighting equipment. Halons are very strong ozone depleters.
AGAGE global measurements of (major) hydrochlorofluorocarbons (HCFCs)
Measurement data for these and other GHGs and ODSs can be found here (data portal).
HCFCs have replaced CFCs in many application as they contribute less to ozone depletion in the stratosphere (upper atmosphere) due to their generally shorter lifetimes in the troposphere (lower atmosphere). Production and consumption of HCFCs is currently also being phased-out by the Montreal Protocol on Substances that Deplete the Ozone Layer to reduce their contribution to ozone depletion.
AGAGE global measurements of (major) hydrofluorocarbons (HFCs)
Measurement data for these and other GHGs and ODSs can be found here (data portal).
HFCs have replaced CFCs and HCFCs in many applications. They do not contribute to ozone depletion, but are quite strong greenhouse gases. The reduction of CFC emissions to protect the ozone layer has had a strong co-benefit of reducing impact on the climate, as CFCs are also strong GHGs. However, this climate benefit of the Montreal Protocol is being eroded due to the sharp rise of HFCs. Therefore, production and consumption of HFCs is now also being phased-out by the Montreal Protocol to reduce the impact of these replacement compounds on the climate.
AGAGE global measurements of PFCs, NF3, SF6 and SO2F2
Measurement data for these and other GHGs and ODSs can be found here (data portal).
PFCs, SF6 and NF3 have atmospheric lifetime of hundreds to tens of thousands of years and their presence in the atmosphere increases the amount of energy absorbed from incoming sunlight for generations to come.
Emissions of these compounds arise from several important industrial activities, such as aluminum production, semiconductor production, and electricity transfer. Efforts to reduce these emissions are under way, but atmospheric abundances keep increasing.
