Web Release Date: April 19,
The Global Atmospheric Environment for the Next Generation
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Joint Research Centre, Institute for Environment and Sustainability, via E. Fermi 1, I-21020, Ispra, Italy, School of Geosciences, University of Edinburgh, Edinburgh, United Kingdom, Department of Geosciences, University of Oslo, Oslo, Norway, Royal Netherlands Meteorological Institute (KNMI), De Bilt, The Netherlands, IIASA, International Institute for Applied Systems Analysis, Laxenburg, Austria, Netherlands Environmental Assessment Agency (RIVM/MNP), Bilthoven, The Netherlands, Frontier Research Center for Global Change, JAMSTEC, Yokohama, Japan, Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland, NASA-Goddard Institute for Space Studies, New York, Goddard Earth Science & Technology Center (GEST), Baltimore, Maryland, Belgian Institute for Space Aeronomy, Brussels, Belgium, Lawrence Livermore National Laboratory, Atmospheric Science Division, Livermore, California, CEA/CNRS, Laboratoire des Sciences du Climat et de l'Environnement, Gif-sur-Yvette, France, Max Planck Institute for Chemistry, Mainz, Germany, Meteo-France, CNRM/GMGEC/CATS, Toulouse, France, NOAA GFDL, Princeton, New Jersey, National Center of Atmospheric Research, Atmospheric Chemistry Division, Boulder, Colorado,Max Planck Institute for Meteorology, Hamburg, Germany, Centre of Atmospheric Science, University of Cambridge, Cambridge, United Kingdom, Met Office, Exeter, United Kingdom, Dipartimento di Fisica, Università L'Aquila, L'Aquila, Italy, and University of Miami, Coral Gables, Florida, NASA-Goddard Space Flight Center, Baltimore, Maryland
Received for review November 28, 2005
Revised manuscript received March 7, 2006
Accepted March 16, 2006
Abstract:
Air quality, ecosystem exposure to nitrogen deposition,
and climate change are intimately coupled problems: we
assess changes in the global atmospheric environment
between 2000 and 2030 using 26 state-of-the-art global
atmospheric chemistry models and three different emissions
scenarios. The first (CLE) scenario reflects implementation
of current air quality legislation around the world, while
the second (MFR) represents a more optimistic case in which
all currently feasible technologies are applied to achieve
maximum emission reductions. We contrast these scenarios
with the more pessimistic IPCC SRES A2 scenario.
Ensemble simulations for the year 2000 are consistent
among models and show a reasonable agreement with
surface ozone, wet deposition, and NO2 satellite observations.
Large parts of the world are currently exposed to high
ozone concentrations and high deposition of nitrogen to
ecosystems. By 2030, global surface ozone is calculated to
increase globally by 1.5 ± 1.2 ppb (CLE) and 4.3 ± 2.2
ppb (A2), using the ensemble mean model results and
associated ±1 
standard deviations. Only the progressive
MFR scenario will reduce ozone, by -2.3 ± 1.1 ppb.
Climate change is expected to modify surface ozone by
-0.8 ± 0.6 ppb, with larger decreases over sea than over
land. Radiative forcing by ozone increases by 63 ± 15
and 155 ± 37 mW m-2 for CLE and A2, respectively, and
decreases by -45 ± 15 mW m-2 for MFR. We compute that
at present 10.1% of the global natural terrestrial ecosystems
are exposed to nitrogen deposition above a critical
load of 1 g N m-2 yr-1. These percentages increase by
2030 to 15.8% (CLE), 10.5% (MFR), and 25% (A2). This study
shows the importance of enforcing current worldwide
air quality legislation and the major benefits of going further.
Nonattainment of these air quality policy objectives,
such as expressed by the SRES-A2 scenario, would further
degrade the global atmospheric environment.
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