Cooperative Institute for Research in Environmental Sciences

Science Rendezvous > 2009 Posters
The presenter is listed in italics. All poster presentations are the property of their respective authors. Please contact the authors for permission to use images, information, or ideas.

The NOAA Annual Greenhouse Gas Index (AGGI)

D.J. Hofmann¹,², J.H. Butler², T.J. Conway², E.J. Dlugokencky², J.W. Elkins², K. Masarie², S.A.. Montzka², R.C. Schnell², and P.P. Tans²

¹ Cooperative Institute for the Research of Environmental Sciences, University of Colorado-Boulder, Boulder, CO, 80309, ² NOAA Earth System Research Laboratory, 325 Broadway, Boulder, Colorado, 80305

For the past 30 years, the U.S. National Oceanic and Atmospheric Administration (NOAA) has monitored climate-forcing and ozone-depleting atmospheric gases. These global measurements have provided input to climate and ozone assessments (e.g., the quadrennial IPCC Climate Reports and WMO/UNEP Ozone Assessments). 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 is designed to enhance the connection between scientists and society by providing a normalized standard that can be easily understood and followed. Measurements are made at baseline climate observatories (Pt. Barrow, Alaska; Mauna Loa, Hawaii; American Samoa; and the South Pole) and flask air samples are collected through global networks, including an international cooperative program for carbon gases. The concept of radiative climate forcing is used to determine the AGGI, which is normalized to 1.00 in 1990, the Kyoto Climate Protocol baseline year. For the year 2006, the AGGI was 1.23, i.e. global radiative forcing by long-lived greenhouse gases has increased 23% since 1990. As will be emphasized, the increase in radiative forcing by carbon dioxide (CO_2 ) alone was about 32% over this time interval. Reductions in the growth rates of methane and the CFCs have effectively tempered the increase of CO_2 since 1990.