A 1° x 1° resolution data set of historical anthropogenic trace gas emissions for the period 1890-1990

An anthropogenic emissions data set has been constructed for CO2, CO, CH4, nonmethane volatile organic compounds, SO2, NOx, N2O, and NH3 spanning the period 1890–1990. The inventory is based on version 2.0 of the Emission Database for Global Atmospheric Research (EDGAR 2.0). In EDGAR the emissions are calculated per country and economic sector using an emission factor approach. Calculations of the emissions with 10 year intervals are based on historical activity statistics and selected emission factors. Historical activity data were derived from the Hundred Year Database for Integrated Environmental Assessments (1890–1990) supplemented with other data and our own estimates. Emission factors account for changes in economical and technological developments in the past. The calculated emissions on a country basis have been interpolated onto a 1°x1° grid. This consistent data set can be used in trend studies of tropospheric trace gases and in environmental assessments, for example, the analysis of historical contributions of regions and countries to environmental forcing like the enhanced greenhouse gas effect, acidification, and eutrofication. The database focuses on energy/industrial and agricultural/waste sources; for completeness, historical biomass-burning estimates where added using a simple and transparent approach. ? 2001 American Geophysical Unio

A global three-dimensional study of the fate of HCFCs and HFC-134a in the troposphere.

International audienc

Changes in nitrogen dioxide and ozone over Southeast and East Asia between year 2000 and 2030 with fixed meteorology

In the framework of the European Network of Excellence ACCENT changes in near-surface and total tropospheric nitrogen dioxide (NO2) and ozone from year 2000 to 2030 have been calculated for the Southeast and East Asian regions using the chemical transport model Oslo CTM-2. Anthropogenic emissions of ozone precursors for the year 2000 case are taken from the International Institute for Applied Systems Analysis (IIASA). Regarding year 2030 emissions, three different scenarios are compared: 1) IIASA 'current legislation' (CLE), where current air quality legislation around the world is implemented; 2) IIASA 'maximum feasible reduction' (MFR), in which all currently available technologies are applied to achieve maximum emission reductions; and 3) the IPCC-SRES A2 scnario, which was used as a high emission estimate in the last IPCC assessment report. While increases in NO2and ozone are calculated when using the CLE scenario, reductions are seen for the MFR scenario. In the SRS A2 case, increases in NO2 are largest, locally leading to ozone reductions at the surface resulting from titration effects. The model calculations suggest that air quality problems will be severely aggravated over Southeast and East Asia if current legislation is not attained

Changing state of the climate system

Chapter 2 assesses observed large-scale changes in climate system drivers, key climate indicators and principal modes of variability. Chapter 3 considers model performance and detection/attribution, and Chapter 4 covers projections for a subset of these same indicators and modes of variability. Collectively, these chapters provide the basis for later chapters, which focus upon processes and regional changes. Within Chapter 2, changes are assessed from in situ and remotely sensed data and products and from indirect evidence of longer-term changes based upon a diverse range of climate proxies. The time-evolving availability of observations and proxy information dictate the periods that can be assessed. Wherever possible, recent changes are assessed for their significance in a longer-term context, including target proxy periods, both in terms of mean state and rates of change

Nitrogen and sulfur deposition on regional and global scales: a multimodel evaluation

We use 23 atmospheric chemistry transport models to calculate current and future (2030) deposition of reactive nitrogen (NOy, NHx) and sulfate (SOx) to land and ocean surfaces. The models are driven by three emission scenarios: (1) current air quality legislation (CLE); (2) an optimistic case of the maximum emissions reductions currently technologically feasible (MFR); and (3) the contrasting pessimistic IPCC SRES A2 scenario. An extensive evaluation of the present-day deposition using nearly all information on wet deposition available worldwide shows a good agreement with observations in Europe and North America, where 60–70% of the model-calculated wet deposition rates agree to within ±50% with quality-controlled measurements. Models systematically overestimate NHx deposition in South Asia, and underestimate NOy deposition in East Asia. We show that there are substantial differences among models for the removal mechanisms of NOy, NHx, and SOx, leading to ±1 s variance in total deposition fluxes of about 30% in the anthropogenic emissions regions, and up to a factor of 2 outside. In all cases the mean model constructed from the ensemble calculations is among the best when comparing to measurements. Currently, 36–51% of all NOy, NHx, and SOx is deposited over the ocean, and 50–80% of the fraction of deposition on land falls on natural (nonagricultural) vegetation. Currently, 11% of the world’s natural vegetation receives nitrogen deposition in excess of the ‘‘critical load’’ threshold of 1000 mg(N) m 2 yr 1. The regions most affected are the United States (20% of vegetation), western Europe (30%), eastern Europe (80%), South Asia (60%), East Asia (40%), southeast Asia (30%), and Japan (50%). Future deposition fluxes are mainly driven by changes in emissions, and less importantly by changes in atmospheric chemistry and climate. The global fraction of vegetation exposed to nitrogen loads in excess of 1000 mg(N) m 2 yr 1 increases globally to 17% for CLE and 25% for A2. In MFR, the reductions in NOy are offset by further increases for NHx deposition. The regions most affected by exceedingly high nitrogen loads for CLE and A2 are Europe and Asia, but also parts of Africa

The global atmospheric environment for the next generation

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, andNO2 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 ó 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