NOAA Research Home » Outstanding Papers
NOAA Research 2007 Outstanding Scientific Paper Awards
“The role of carbon dioxide in climate forcing from 1979 to 2004: introduction of the Annual Greenhouse Gas Index”
ABSTRACT
High-precision measurements of CO2, CH4, N2O, CFC-12, CFC-11 (major greenhouse
gases) and 10 minor halogenated gases from a globally distributed network
of air sampling sites are used to calculate changes in radiative climate
forcing since the pre-industrial era (1750) for the period of measurement,
1979–2004. The five major greenhouse gases account for about 97%
of the direct radiative forcing by long-lived gases. The fraction of the
sum of radiative forcings by all long-lived gases that is due to CO2 has
grown from 60% to 63% over this time. Though the long-term increase in
this sum is due primarily to increased anthropogenic emissions of these
radiatively important gases, interannual variations in the growth rate
of radiative forcing due to CO2 are large and likely related to natural
phenomena such as volcanic eruptions and ENSO events. The annual value
of the total global radiative forcing of the long-lived gases is used to
define an Annual Greenhouse Gas Index (AGGI). The AGGI is normalized to
1990, the Kyoto Protocol baseline year. FULL
TEXT 
Trends in radiative forcing growth rates of the five major greenhouse gases. (larger image)
Annual growth rate in radiative forcing from 1980 to 2004 by long-lived greenhouse gases. The total integrated radiative forcing is also shown (red curve, right axis). CH4 data prior to 1983 are from Etheridge et al. (1998). (larger image)
The NOAA Earth System Research Laboratory global cooperative air sampling network used to determine the AGGI. Closed circles are weekly flask sampling sites and open squares are continuous measurement sites. (larger image)
Sum of annual radiative climate forcings by long-lived greenhouse gases relative to 1750. The AGGI (right vertical axis) is indexed to 1 in 1990. (larger image)
NOAA Research Home » Outstanding Papers
CLIMATE · OCEANS,
GREAT LAKES, and COASTS · WEATHER
and AIR QUALITY
ABOUT US · RESEARCH
PROGRAMS · EDUCATION · HOME
10/23/07