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| Titel |
The NOAA Annual Greenhouse Gas Index - 2012 Update |
| VerfasserIn |
J. H. Butler, S. A. Montzka, T. J. Conway, E. J. Dlugokencky, J. W. Elkins, K. A. Masari, R. C. Schnell, P. P. Tans |
| Konferenz |
EGU General Assembly 2012
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250068931
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| Zusammenfassung |
| For the past several decades, 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 databases, analyses, and various relevant products,
including national and international climate assessments. To make these data more useful
and available, NOAA several years ago released its 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. The long-lived gases capture most of the radiative forcing,
and uncertainty in their measurement is very small. This allows us to provide a
robust measure and assessment of the long-term, radiative influence of these gases.
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 60 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, Colorado, using WMO standard reference gases prepared by
NOAA/ESRL. The AGGI is normalized to 1.00 in 1990, the Kyoto Climate Protocol
baseline year. In 2010, the AGGI was 1.29, indicating that global radiative forcing
by long-lived greenhouse gases had increased 29% 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 85-90% of this
increase each year. After nearly a decade of virtually level concentrations in the
atmosphere, methane (CH4) increased measurably over the past 2-3 years, as did its
contribution to radiative forcing. In this presentation, preliminary values for 2011 will be
evaluated and discussed with respect to the contributions from CO2, CH4,nitrous
oxide (N2O), chlorofluorocarbons (CFCs), and other emerging greenhouse gases. |
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