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Global greenhouse gas (GHG) emissions can be traced to five economic sectors: energy, industry, buildings, transport and AFOLU (agriculture, forestry and other land uses). In this topical review, we synthesise the literature to explain recent trends in global and regional emissions in each of these sectors. To contextualise our review, we present estimates of GHG emissions trends by sector from 1990 to 2018, describing the major sources of emissions growth, stability and decline across ten global regions. Overall, the literature and data emphasise that progress towards reducing GHG emissions has been limited. The prominent global pattern is a continuation of underlying drivers with few signs of emerging limits to demand, nor of a deep shift towards the delivery of low and zero carbon services across sectors. We observe a moderate decarbonisation of energy systems in Europe and North America, driven by fuel switching and the increasing penetration of renewables. By contrast, in rapidly industrialising regions, fossil-based energy systems have continuously expanded, only very recently slowing down in their growth. Strong demand for materials, floor area, energy services and travel have driven emissions growth in the industry, buildings and transport sectors, particularly in Eastern Asia, Southern Asia and South-East Asia. An expansion of agriculture into carbon-dense tropical forest areas has driven recent increases in AFOLU emissions in Latin America, South-East Asia and Africa. Identifying, understanding, and tackling the most persistent and climate-damaging trends across sectors is a fundamental concern for research and policy as humanity treads deeper into the Anthropocene.

The new version of the Emissions Database for Global Atmospheric Research (EDGAR v4.3.2) compiles gaseous and particulate air pollutant emissions, making use of the same anthropogenic sectors, time period (1970–2012), and international activity data that is used for estimating GHG emissions, as described in a companion paper (Janssens-Maenhout et al., 2017). All human activities, except large scale biomass burning and land use, land-use change, and forestry are included in the emissions calculation. The bottom-up compilation methodology of sector-specific emissions was applied consistently for all world countries, providing methodological transparency and comparability between countries. In addition to the activity data used to estimate GHG emissions, air pollutant emissions are determined by the process technology and end-of-pipe emission reduction abatements. Region-specific emission factors and abatement measures were selected from recent available scientific literature and reports. Compared to previous versions of EDGAR, the EDGAR v4.3.2 dataset covers all gaseous and particulate air pollutants, has extended time series (1970–2012), and has been evaluated with quality control and quality assurance (QC and QA) procedures both for the emission time series (e.g. particulate matter – PM – mass balance, gap-filling for missing data, the split-up of countries over time, few updates in the emission factors, etc.) and grid maps (full coverage of the world, complete mapping of EDGAR emissions with sector-specific proxies, etc.). This publication focuses on the gaseous air pollutants of CO, NOx, SO2, total non-methane volatile organic compounds (NMVOCs), NH3, and the aerosols PM10, PM2.5, black carbon (BC), and organic carbon (OC). Considering the 1970–2012 time period, global emissions of SO2 increased from 99 to 103 Mt, CO from 441 to 562 Mt, NOx from 68 to 122 Mt, NMVOC from 119 to 170 Mt, NH3 from 25 to 59 Mt, PM10 from 37 to 65 Mt, PM2.5 from 24 to 41 Mt, BC from 2.7 to 4.5 Mt, and OC from 9 to 11 Mt. We present the country-specific emission totals and analyze the larger emitting countries (including the European Union) to provide insights on major sector contributions. In addition, per capita and per GDP emissions and implied emission factors – the apparent emissions per unit of production or energy consumption – are presented. We find that the implied emission factors (EFs) are higher for low-income countries compared to high-income countries, but in both cases decrease from 1970 to 2012. The comparison with other global inventories, such as the Hemispheric Transport of Air Pollution Inventory (HTAP v2.2) and the Community Emission Data System (CEDS), reveals insights on the uncertainties as well as the impact of data revisions (e.g. activity data, emission factors, etc.). As an additional metric, we analyze the emission ratios of some pollutants to CO2 (e.g. CO∕CO2, NOx∕CO2, NOx∕CO, and SO2∕CO2) by sector, region, and time to identify any decoupling of air pollutant emissions from energy production activities and to demonstrate the potential of such ratios to compare to satellite-derived emission data. Gridded emissions are also made available for the 1970–2012 historic time series, disaggregated for 26 anthropogenic sectors using updated spatial proxies. The analysis of the evolution of hot spots over time allowed us to identify areas with growing emissions and where emissions should be constrained to improve global air quality (e.g. China, India, the Middle East, and some South American countries are often characterized by high emitting areas that are changing rapidly compared to Europe or the USA, where stable or decreasing emissions are evaluated). Sector- and component-specific contributions to grid-cell emissions may help the modelling and satellite communities to disaggregate atmospheric column amounts and concentrations into main emitting sectors. This work addresses not only the emission inventory and modelling communities, but also aims to broaden the usefulness of information available in a global emission inventory such as EDGAR to also include the measurement community. Data are publicly available online through the EDGAR website http://edgar.jrc.ec.europa.eu/overview.php?v=432_AP and registered under https://doi.org/10.2904/JRC_DATASET_EDGAR.

Speciated mercury gridded emissions inventories together with chemical transport models and concentration measurements are essential when investigating both the effectiveness of mitigation measures and the mercury cycle in the environment. Since different mercury species have contrasting behaviour in the atmosphere, their proportion in anthropogenic emissions could determine the spatial impacts. In this study, the time series from 1970 to 2012 of the EDGARv4.tox2 global mercury emissions inventory are described; the total global mercury emission in 2010 is 1772 tonnes. Global grid-maps with geospatial distribution of mercury emissions at a 0.1° × 0.1° resolution are provided for each year. Compared to the previous tox1 version, tox2 provides updates for more recent years and improved emissions in particular for agricultural waste burning, power generation and artisanal and small-scale gold mining (ASGM) sectors. We have also developed three retrospective emissions scenarios based on different hypotheses related to the proportion of mercury species in the total mercury emissions for each activity sector; improvements in emissions speciation are seen when using information primarily from field measurements. We evaluated them using the GEOS-Chem 3-D mercury model in order to explore the influence of speciation shifts, to reactive mercury forms in particular, on regional wet deposition patterns. The reference scenario S1 (EDGARv4.tox2_S1) uses speciation factors from the Arctic Monitoring and Assessment Programme (AMAP); scenario S2 (“EPA_power”) uses factors from EPA's Information Collection Request (ICR); and scenario S3 (“Asia_filedM”) factors from recent scientific publications. In the reference scenario, the sum of reactive mercury emissions (Hg-P and Hg2+) accounted for 25.3% of the total global emissions; the regions/countries that have shares of reactive mercury emissions higher than 6% in total global reactive mercury are China+ (30.9%), India+ (12.5%) and the United States (9.9%). In 2010, the variations of reactive mercury emissions amongst the different scenarios are in the range of −19.3 t/yr (China+) to 4.4 t/yr (OECD_Europe). However, at the sector level, the variation could be different, e.g., for the iron and steel industry in China reaches 15.4 t/yr. Model evaluation at the global level shows a variation of approximately ±10% in wet deposition for the three emissions scenarios. An evaluation of the impact of mercury speciation within nested grid sensitivity simulations is performed for the United States and modelled wet deposition fluxes are compared with measurements. These studies show that using the S2 and S3 emissions of reactive mercury, can improve wet deposition estimates near sources.

In the context of recent discussions at the UN climate negotiations we compared several ways of calculating historical greenhouse gas (GHG) emissions, and assessed the effect of these different approaches on countries’ relative contributions to cumulative global emissions. Elements not covered before are: (i) including recent historical emissions (2000–2010), (ii) discounting historical emissions to account for technological progress; (iii) deducting emissions for ‘basic needs’; (iv) including projected emissions up to 2020, based on countries’ unconditional reduction proposals for 2020. Our analysis shows that countries’ contributions vary significantly based on the choices made in the calculation: e.g. the relative contribution of developed countries as a group can be as high as 80 % when excluding recent emissions, non-CO2 GHGs, and land-use change and forestry CO2; or about 48 % when including all these emissions and discounting historical emissions for technological progress. Excluding non-CO2 GHGs and land-use change and forestry CO2 significantly changes relative historical contributions for many countries, altering countries’ relative contributions by multiplicative factors ranging from 0.15 to 1.5 compared to reference values (i.e. reference contribution calculations cover the period 1850-2010 and all GHG emissions). Excluding 2000–2010 emissions decreases the contributions of most emerging economies (factor of up to 0.8). Discounting historical emissions for technological progress reduces the relative contributions of some developed countries (factor of 0.8) and increases those of some developing countries (factor of 1.2–1.5). Deducting emissions for ‘basic needs’ results in smaller contributions for countries with low per capita emissions (factor of 0.3–0.5). Finally, including projected emissions up to 2020 further increases the relative contributions of emerging economies by a factor of 1.2, or 1.5 when discounting pre-2020 emissions for technological progress.

A methodology is presented here to assess the potential long-term contribution of non-CO2 greenhouse gases in mitigation scenarios. The analysis shows the future development of the mitigation potential of non-CO2 gases (as a function of changes in technology and implementation barriers) to represent a crucial parameter for the overall costs of mitigation scenarios. The recently developed marginal abatement cost curves for 2010 in the EMF-21 project are taken as the starting point. First-order estimates were made of the future maximum attainable reduction potentials and costs on the basis of available literature. The set of MAC curves developed was used in a multi-gas analysis for stabilising greenhouse gas concentrations at 550 ppm CO2-equivalent. Including future development for the non-CO2 mitigation options not only increases their mitigation potential but also lowers the overall costs compared to situations where no development is assumed (3–21% lower in 2050 and 4–26% lower in 2100 in our analysis). Along with the fluorinated gases, energy-related methane emissions make up the largest share in total non-CO2 abatement potential as they represent a large emission source and have a large potential for reduction (towards 90% compared to baseline in 2100). Most methane and nitrous oxide emissions from landuse-related sources are less simple to abate, with an estimated abatement potential in 2100 of around 60% and 40%, respectively.

Based on the EDGAR 3.2 emission datasets, we present the relative importance of this source globally, regionally, and for individual countries as part of total fossil fuel-related emissions, based on the IPCC Tier 1 reference calculation using IEA/UN data for 1970–1995. Thus, we also show the trends of these shares as well as the type of non-energy source (chemical feedstock, industry in general, transport, other sectors) and the fuel type (solid, liquid, gaseous). The share of CO2 from non-energy use (NEU) is increasing over time; globally from 1% in 1970 to almost 3% of total fossil fuel emissions of CO2 in 1995. Expressed as fraction of total CO2 emissions from the industry sector, the shares were about 4% in 1970, 7% in 1990 and 12% in 1995 for global total emissions. In most regions chemical feedstock emissions of CO2 have become increasingly important. The share of CO2 from feedstocks in total CO2 from NEU has increased globally from about 55% in 1970 to 65% in 1990 and even 80% in 1995. This large increase is largely responsible for the increasing share of total CO2 NEU emissions. With an uncertainty of the order of 10–30% in CO2 from NEU of oil products there should be ample room for improvement.

The Emission Database for Global Atmospheric Research (EDGAR) provides a time-series of man-made emissions of greenhouse gases and short-lived atmospheric pollutants from 1970 to 2008. Mercury is included in EDGARv4.tox1, thereby enriching the spectrum of multi-pollutant sources in the database. With an average annual growth rate of 1.3% since 1970, EDGARv4 estimates that the global mercury emissions reached 1287 tonnes in 2008. Specifically, gaseous elemental mercury (GEM) (Hg[superscript 0]) accounted for 72% of the global total emissions, while gaseous oxidised mercury (GOM) (Hg[superscript 2 +]) and particle bound mercury (PBM) (Hg-P) accounted for only 22% and 6%, respectively. The less reactive form, i.e., Hg[superscript 0], has a long atmospheric residence time and can be transported long distances from the emission sources. The artisanal and small-scale gold production, accounted for approximately half of the global Hg[superscript 0] emissions in 2008 followed by combustion (29%), cement production (12%) and other metal industry (10%). Given the local-scale impacts of mercury, special attention was given to the spatial distribution showing the emission hot-spots on gridded 0.1° × 0.1° resolution maps using detailed proxy data. The comprehensive ex-post analysis of the mitigation of mercury emissions by end-of-pipe abatement measures in the power generation sector and technology changes in the chlor-alkali industry over four decades indicates reductions of 46% and 93%, respectively. Combined, the improved technologies and mitigation measures in these sectors accounted for 401.7 tonnes of avoided mercury emissions in 2008. A comparison shows that EDGARv4 anthropogenic emissions are nearly equivalent to the lower estimates of the United Nations Environment Programme (UNEP)'s mercury emissions inventory for 2005 for most sectors. An evaluation of the EDGARv4 global mercury emission inventory, including mercury speciation, was performed using the GEOS-Chem global 3-D mercury model. The model can generally reproduce both spatial variations and long-term trends in total gaseous mercury concentrations and wet deposition fluxes., National Science Foundation (U.S.) (Atmospheric Chemistry Program Grant 1053648)

Global emission inventories with 1° × 1° resolution were compiled for nitrogen oxides (NO + NO 2 , together denoted as NO x ), ammonia (NH 3 ) and nitrous oxide (N 2 O) emissions. For NO x the estimated global anthropogenic emission for 1990 is about 31 million ton N year −1 . The major anthropogenic sources identified include fossil fuel combustion (70%, of which the major sources are road transport and power plants) and biomass burning (20%). Natural sources contribute about 19 million ton N year −1 , mainly lightning and soil processes. For NH 3 the estimated global emission for 1990 is about 54 million ton N year −1 . The major sources identified include excreta from domestic animals and wild animals, use of synethetic N fertilisers, oceans and biomass burning. About half of the global emission comes from Asia, and about 70% is related to food production. For N 2 O the major sources considered include fertilised arable land, animal excreta, soils under natural vegetation, oceans, and biomass burning. The global source of N 2 O is about 15 million ton N 2 O-N year −1 of which about 30% is related to food production. All three inventories are available on a sectoral basis on a 1° × 1° grid for input to global atmospheric models and on a regional/country basis for policy analysis.

A global emissions inventory for ammonia (NH3) has been compiled for the main known sources on a 1° × 1° grid, suitable for input to global atmospheric models. The estimated global emission for 1990 is about 54 Tg N yr−1. The major sources identified include excreta from domestic animals (21.6 Tg N yr−1) and wild animals (0.1 Tg N yr−1), use of synthetic N fertilizers (9.0 Tg N yr−1), oceans (8.2 Tg N yr−1), biomass burning (5.9 Tg N yr−1), crops (3.6 Tg N yr−1), human population and pets (2.6 Tg N yr−1), soils under natural vegetation (2.4 Tg N yr−1), industrial processes (0.2 Tg N yr−1 ), and fossil fuels (0.1 Tg N yr−1). About half of the global emission comes from Asia, and about 70% is related to food production. The regions with highest emission rates are located in Europe, the Indian subcontinent, and China, reflecting the patterns of animal densities and type and intensity of synthetic fertilizer use. The overall uncertainty in the global emission estimate is 25%, while the uncertainty in regional emissions is much greater. As the global human population will show considerable growth in the coming decades, food production and associated NH3 emissions are likely to increase as well.

National-scale inventories of soil organic carbon (SOC) and forest floor carbon (FFC) stocks have a high uncertainty. Inventories are often based on the interpolation of sampled information, often using a number of covariables to help such interpolation. The rationale for the choice of these covariables is not always documented, despite the fact that many local-scale studies have identified the factors explaining spatial variability of SOC and FFC stocks. These studies indicate, among others the importance of long-term land use history. Despite this, information on the effects of land use history has never been used to explain variability of carbon stocks in national-scale inventories. We designed an alternative method to improve national-scale inventories of SOC and FCC for the Dutch sand area that takes stock of the findings of detailed case studies. Determinants for SOC and FFC stocks derived from landscape-scale case studies were used to map national-scale spatial variability and to calculate national totals. The resulting national-scale spatial distribution was compared with the SOC stock map from the current Dutch greenhouse gas inventory. Using land use history to explain SOC variability decreased the error of the SOC stock estimate in 60 % of the area. The error in FFC stocks decreased in half of the forest area after including soil fertility, tree species, and forest age as explanatory factors. Estimates with reduced uncertainty will make land use and land management a more attractive and acceptable mitigation option to reduce emissions of greenhouse gases for the LULUCF sector. © 2012 Springer Science+Business Media New York.

This synthesis discusses the emissions of carbon dioxide from fossil-fuel combustion and cement production. While much is known about these emissions, there is still much that is unknown about the details surrounding these emissions. This synthesis explores our knowledge of these emissions in terms of why there is concern about them; how they are calculated; the major global efforts on inventorying them; their global, regional, and national totals at different spatial and temporal scales; how they are distributed on global grids (i.e., maps); how they are transported in models; and the uncertainties associated with these different aspects of the emissions. The magnitude of emissions from the combustion of fossil fuels has been almost continuously increasing with time since fossil fuels were first used by humans. Despite events in some nations specifically designed to reduce emissions, or which have had emissions reduction as a byproduct of other events, global total emissions continue their general increase with time. Global total fossil-fuel carbon dioxide emissions are known to within 10 % uncertainty (95 % confidence interval). Uncertainty on individual national total fossil-fuel carbon dioxide emissions range from a few percent to more than 50 %. This manuscript concludes that carbon dioxide emissions from fossil-fuel combustion continue to increase with time and that while much is known about the overall characteristics of these emissions, much is still to be learned about the detailed characteristics of these emissions.

Deforestation is the second largest anthropogenic source of carbon dioxide to the atmosphere, after fossil fuel combustion. Following a budget reanalysis, the contribution from deforestation is revised downwards, but tropical peatlands emerge as a notable carbon dioxide source.

In 2004, the Joint Research Centre (JRC) of the European Commission, the Netherlands Environmental Assessment Agency (MNP) and the Max Plank Institute for Chemistry (MPIC) started a project to create fast (bi-)annual updates of the EDGAR global emission inventory system, based on the more detailed previous version 3.2. Here, the key features of the Emission Database for Global Atmospheric Research, EDGAR 3 are first summarized, and then the compilation of recent global trends having a major influence on variables and the new 'Fast Track' approach to estimate recent emissions of greenhouse gases and air pollutants in 2000 at a country-specific level are described. Also provided is an overview of the approaches and data sources used for this EDGAR 3.2 Fast Track 2000 dataset, the different source sectors and the accuracies achieved, with a focus on anthropogenic sources of methane and nitrous oxide. Results of global emission trends for four air pollutants are also briefly addressed. Results for various sources and greenhouse gases at regional and national scales and on 11 degree grid have been made available on the EDGAR website.

The mathematical modelling of the transport and transformation of trace species in the atmosphere is one of the scientific tools currently used to assess atmospheric chemistry, air quality, and climatic conditions. One of the most important inputs to such models are accurate inventories of emissions of the trace species included in the study at the appropriate sectoral, spatial, temporal, and species resolution. In addition, from the management perspective detailed information on emissions is also required at high resolution for the design of policies aimed at reducing emissions of pollutants, and for the evaluation of the efficiency of such policies.

A set of global greenhouse gas emission inventories has been compiled per source category for the 1990 annual emissions of the direct greenhouse gases CO2, CH4 and N2O, as well as of the indirect greenhouse gases (ozone precursors) CO, NOx and NMVOC, and of SO2. The inventories are available by sector, both on a per country/region basis and on a 1°×1° grid. Developed by TNO and RIVM for constructing the Emission Database for Global Atmospheric Research (EDGAR) Version 2.0, in co-operation with the Global Emission Inventory Activity (GEIA) of IGAC/IGBP, the inventories meet the needs of both policy-makers and atmospheric modellers. The data sources for activity data, emission factors and grid maps are discussed with the focus on anthropogenic sources of primarily CO2, CH4 and N2O. The estimates of a standard group of anthropogenic sources are presented for each compound per world region. © 1999 Elsevier Science Ltd.

A global emission inventory of carbon monoxide (CO) emissions with 1° × 1° latitude-longitude resolution was compiled for 1990 on a sectoral basis. The sectoral sources considered include large-scale biomass burning (29%, of which savanna burning, 18%, and deforestation, 11%), fossil fuel combustion (27%, predominantly in road transport), biofuel combustion (19%, predominantly fuelwood combustion), agricultural waste burning (21%) and industrial process sources (4%). The inventory was compiled using mostly national statistics as activity data, emission factors at global or country level, and specific grid maps to convert, by sector, country total emissions to the 1° × 1° grid. A special effort was made to compile a global inventory of biofuel use, since this was considered to be a significant source on a global level, and a major source in some regions such as India and China. The global anthropogenic source of CO in 1990 is estimated at about 974 Tg CO yr-1. The inventory is available on a sectoral basis on a 1° × 1° grid for input to global atmospheric models and on a regional/country basis for policy analysis. © 1999 Elsevier Science Ltd. All rights reserved.

To meet the urgent need of atmospheric chemistry and climate modellers a global emissions source database called EDGAR has been developed jointly by TNO and RIVM to estimate for 1990, on a regional and on a grid basis, annual emissions of greenhouse gases (CO 2 , CH 4 , N 2 O, CO, NO x , non-methane VOC, SO x ), of NH 3 , and of ozone depleting compounds (halocarbons). The aim was to establish the global emissions from both anthropogenic and biogenic sources: a complete set of data required to estimate the total source strength of the various gases with an 1 o ×1 o resolution (altitude resolution of 1 km), as agreed upon in the Global Emissions Inventory Activity (GEIA) of the International Atmospheric Chemistry Programme (IGAC). The data comprise demographic data, social and economic factors, land use distributions and emission factors (with due emphasis on the uncertainty). As understanding in this field is still changing, due attention is paid to flexibility regarding the disaggregation of sources, spatial and temporal resolution and species. The objective and methodology chosen for the construction of the database are presented, as well as the type and sources of data and the approach used for data collection. As an example, the construction of the N 2 O inventory is discussed.

Publisher Summary This chapter discusses the IMAGE 2.0 model, a multi-disciplinary, integrated model designed to simulate the dynamics of the global society–biosphere–climate system. It focuses on the scientific aspects of the model, whose objective is to investigate linkages and feedbacks in the global system, and to evaluate consequences of climate policies. Dynamic calculations are performed to year 2100, with a spatial scale ranging from grid (0.5 0 × 0.5 0 latitude–longitude) to world political regions, depending on the sub-model. A total of 13 submodels make up IMAGE 2.0, and they are organized into three fully linked subsystems: Energy-Industry, Terrestrial-Environment, and Atmosphere-Ocean. The fully linked model has been tested against data from 1970 to 1990, and after calibration can reproduce the following observed trends: regional energy consumption and energy-related emissions, terrestrial flux of carbon dioxide and emissions of greenhouse gases, concentrations of greenhouse gases in the atmosphere, and transformation of land cover. The model can also simulate current zonal average surface and vertical temperatures. The main innovation of the IMAGE 2.0 model is its presentation of a geographically-detailed, global, and dynamic view of the linked society–biosphere–climate system. With respect to society, the model represents in some detail the relation between economic and demographic trends and the generation of greenhouse gas emissions.

Hydrofluorocarbons (HFCs) and hydrochlorofluorocarbons (HCFCs) are important substitutes for chlorofluorocarbons (CFCs) and halons. HCFCs have a lower Ozone Depleting Potential (ODP) than CFCs and halons, and are therefore considered temporary substitutes, while HFCs have zero ODP. In addition to ODP many halocarbons also have a Global Warming Potential (GWP). We developed this paper three different scenarios, globally as well as for the Netherlands: (1) the ‘London’ scenarios, in which HCFCs and HFCs are used unrestrictedly to replace CFCs and halons. As a result the global warming effect by halocarbons may increase the future. HFCs are found to be the main contributors to future radiative forcing by halocarbons. In the Netherlands the increasing use of HFCs results in a doubling of the release of CO2-equivalents from all halocarbons by 2010 compared to 1990 (assuming a zero GWP for CFCs and halons, to include potential indirect negative radiative effects via stratospheric ozone destruction); (2) the ‘Copenhagen’ scenarios, which consider an additional phase-out of HCFCs, after which the use of HFCs increases. The higher GWPs of HFCs compared to other halocarbons result in an increase of global warming by halocarbons. Dutch CO2 equivalent halocarbon consumption could increase by a factor 2 to 4 after an HCFC phase-out, if no additional measures for HFCs are implemented; (3) the ‘Additional Policy’ scenario, which assumes the use of compounds, that have zero ODP and a relatively small GWP, which are available for most applications. Such additional measures will reduce CO2-eq. halocarbon consumption substantially. The share of halocarbons in total CO2 equivalent emissions in the Netherlands will increase from 3 to 7% to 11% in 2010 (assuming a zero GWP for CFCs and halons). Substitution by low or zero GWP alternatives leads to stabilization of greenhouse gas emissions by 2010 at the 1990 level, while without additional policy for HFCs Dutch greenhouse gas emissions may increase by 10% or more.

In the integrated IMAGE 2.0 model the “Energy-Industry System” is implemented as a set of models to develop global scenarios for energy use and industrial processes and for the related emissions of greenhouse gases on a region specific basis. The Energy-Economy model computes total energy use, with a focus on final energy consumption in end-use sectors, based on economic activity levels and the energy conservation potential (“end-use approach”). The Industrial Production and Consumption model computes the future levels of activities other than energy use, which lead to greenhouse gas emissions, based on relations with activities defined in the Energy-Economy model. These two models are complemented by two emissions models, to compute the associated emissions by using emission factors per compound and per activity defined. For investigating energy conservation and emissions control strategy scenarios various techno-economic coefficients in the model can be modified. In this paper the methodology and implementation of the “Energy-Industry System” models is described as well as results from their testing against data for the period 1970–1990. In addition, the application of the models is presented for a specific scenario calculation. Future extensions of the models are in preparation.

Inventories with 1°×1° resolution were compiled of nitrous oxide (N2O) emissions from fertilized arable land, animal excreta, postclearing effects on soil emissions, fossil fuel and fuelwood combustion, and industrial N2O sources. For other sources of N2O, including soils under natural vegetation, oceans, and biomass burning, published inventories were used. From these inventories the annual N2O emission was calculated for four broad latitudinal zones covering the globe. Uncertainties were assessed by comparing variants of inventories with source estimates inferred from inverse modeling techniques. Major uncertainties occur in the tropics, where small errors in both soil and oceanic emission estimates may have large repercussions for the zonal distributions. Although there may still be many poorly known and unidentified N2O sources, the analysis has resulted in improved understanding of some sources, i.e., (1) the oceanic N2O emission may be more important than assumed in recent global N2O budgets, with a major portion stemming from the 30°–90°S zone; (2) the N2O emission from animal excreta forms a significant global source; (3) most of the N2O from arable lands and grasslands, including effects of synthetic fertilizers and animal excreta, comes from the northern hemisphere; accounting for only the synthetic-fertilizer effect on N2O emission leads to an underestimation of the emission from arable lands; (4) fossil fuel combustion and industrial N2O sources are dominant in the 30°–90°N zone, while N2O from fuelwood combustion is mainly produced in the 0°–30°N zone; (5) the estimation of enhanced N2O soil emission following tropical forest clearing that has accounted for gradually declining N2O fluxes, along with aging of the clearing leads to a global emission that is significant but lower than previous estimates; (6) most of the N2O from coastal marine and freshwater systems and soil N2O emission resulting from N deposition probably comes from the northern hemisphere.