RADIATIVE CLIMATE FORCING BY LONG-LIVED GREENHOUSE GASES:
THE NOAA ANNUAL GREENHOUSE GAS INDEX (AGGI)

NOAA Earth System Research Laboratory, R/GMD, 325 Broadway, Boulder, CO
80305-3328


INTRODUCTION

The perturbation to radiative climate forcing which has the largest
magnitude and the least scientific uncertainty is the forcing related
to changes in long-lived and well mixed greenhouse gases, in particular
carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O) and the
halocarbons (mainly CFCs). Greenhouse gas concentrations are analyzed
in terms of the changes in radiative forcing since 1750 for the period
beginning in 1979. The change in annual total radiative forcing by all
the long-lived greenhouse gases since the pre-industrial era (1750) is
used to define the NOAA Annual Greenhouse Gas Index (AGGI), which was
introduced in 2005 (Hofmann et al., 2006).

The NOAA AGGI is designed to enhance the connection between scientists
and society by providing a normalized standard that can be easily
understood and followed. The contribution of long-lived greenhouse
gases to climate forcing is well understood by scientists and has been
reported by NOAA through a range of national and international
assessments. Nevertheless, the language of scientists (for example,
watts per square meter per year) often eludes policy makers, educators,
and the general public. This index is designed to help bridge that gap.

Please see:
http://www.cmdl.noaa.gov/aggi/