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| Titel |
NOAA Annual Greenhouse Gas Index (AGGI) - Update 2008 |
| VerfasserIn |
J. H. Butler, D. J. Hofmann, T. J. Conway, E. J. Dlugokencky, J. W. Elkins, K. Masarie, S. A. Montzka, R. C. Schnell, P. P. Tans |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250024588
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| Zusammenfassung |
| For the past 30 years, the U.S. National Oceanic and Atmospheric Administration (NOAA)
has monitored all of the long-lived atmospheric greenhouse gases. These global
measurements have provided input to climate assessments (e.g., the quadrennial IPCC
Climate Reports, as well as National Assessments, such as those under the auspices of the US
Climate Change Science Program). Recently, efforts to make these data more useful and
available have been undertaken through release of the NOAA Annual Greenhouse Gas Index
(AGGI), http://www.esrl.noaa.gov/gmd/aggi . This index, based on the climate forcing
properties of long-lived greenhouse gases, was designed to enhance the connection
between scientists and society by providing a normalized standard that can be easily
understood and followed. Continuous greenhouse gas measurements are made at
baseline climate observatories (Pt. Barrow, Alaska; Mauna Loa, Hawaii; American
Samoa; and the South Pole) and weekly flask air samples are collected through a
global network of over 70 sites, including an international cooperative program
for carbon dioxide and other greenhouse gases. The gas samples are analyzed at
NOAA’s Earth System Research Laboratory (NOAA/ESRL) in Boulder, using WMO
standard reference gases prepared by NOAA/ESRL. The AGGI is normalized to
1.00 in 1990, the Kyoto Climate Protocol baseline year. For the year 2007, the
AGGI was 1.24, i.e. global radiative forcing by long-lived greenhouse gases has
increased 24% since 1990. The increase in the contribution form carbon dioxide (CO2)
alone was about 32% over this interval. Reductions in the growth rates of methane
and the CFCs have effectively tempered the increase of CO2 since 1990. During
the 1980s CO2 accounted for about 50-60%% of the annual increase in radiative
forcing by long-lived greenhouse gases, whereas, since 2000, it has accounted for
90% of this increase. The contribution from methane (CH4) in 2007 increased
for the first time since 1999. Preliminary values for 2008 will be evaluated and
discussed with respect to the contributions from CO2, CH4,nitrous oxide (N2O),
chlorofluorocarbons (CFCs), and other evolving greenhouse gases in this presentation. |
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