Greet Janssens-Maenhout

Simultaneously Mitigating Near-Term Climate Change and Improving Human Health and Food Security

Why Wait? Tropospheric ozone can be dangerous to human health, can be harmful to vegetation, and is a major contributor to climate warming. Black carbon also has significant negative effects on health and air quality and causes warming of the atmosphere. Shindell et al. (p. 183) present results of an analysis of emissions, atmospheric processes, and impacts for each of these pollutants. Seven measures were identified that, if rapidly implemented, would significantly reduce global warming over the next 50 years, with the potential to prevent millions of deaths worldwide from outdoor air pollution. Furthermore, some crop yields could be improved by decreasing agricultural damage. Most of the measures thus appear to have economic benefits well above the cost of their implementation. Reducing anthropogenic emissions of methane and black carbon would have multiple climate and health benefits. Tropospheric ozone and black carbon (BC) contribute to both degraded air quality and global warming. We considered ~400 emission control measures to reduce these pollutants by using current technology and experience. We identified 14 measures targeting methane and BC emissions that reduce projected global mean warming ~0.5°C by 2050. This strategy avoids 0.7 to 4.7 million annual premature deaths from outdoor air pollution and increases annual crop yields by 30 to 135 million metric tons due to ozone reductions in 2030 and beyond. Benefits of methane emissions reductions are valued at

Global Air Quality and Health Co-benefits of Mitigating Near-Term Climate Change through Methane and Black Carbon Emission Controls

700 to

Verifying Greenhouse Gas Emissions: Methods to Support International Climate Agreements

5000 per metric ton, which is well above typical marginal abatement costs (less than

Trend analysis from 1970 to 2008 and model evaluation of EDGARv4 global gridded anthropogenic mercury emissions

250). The selected controls target different sources and influence climate on shorter time scales than those of carbon dioxide–reduction measures. Implementing both substantially reduces the risks of crossing the 2°C threshold.

Technical note: Coordination and harmonization of the multi-scale, multi-model activities HTAP2, AQMEII3, and MICS-Asia3: simulations, emission inventories, boundary conditions, and model output formats

Background: Tropospheric ozone and black carbon (BC), a component of fine particulate matter (PM ≤ 2.5 µm in aerodynamic diameter; PM2.5), are associated with premature mortality and they disrupt global and regional climate. Objectives: We examined the air quality and health benefits of 14 specific emission control measures targeting BC and methane, an ozone precursor, that were selected because of their potential to reduce the rate of climate change over the next 20–40 years. Methods: We simulated the impacts of mitigation measures on outdoor concentrations of PM2.5 and ozone using two composition-climate models, and calculated associated changes in premature PM2.5- and ozone-related deaths using epidemiologically derived concentration–response functions. Results: We estimated that, for PM2.5 and ozone, respectively, fully implementing these measures could reduce global population-weighted average surface concentrations by 23–34% and 7–17% and avoid 0.6–4.4 and 0.04–0.52 million annual premature deaths globally in 2030. More than 80% of the health benefits are estimated to occur in Asia. We estimated that BC mitigation measures would achieve approximately 98% of the deaths that would be avoided if all BC and methane mitigation measures were implemented, due to reduced BC and associated reductions of nonmethane ozone precursor and organic carbon emissions as well as stronger mortality relationships for PM2.5 relative to ozone. Although subject to large uncertainty, these estimates and conclusions are not strongly dependent on assumptions for the concentration–response function. Conclusions: In addition to climate benefits, our findings indicate that the methane and BC emission control measures would have substantial co-benefits for air quality and public health worldwide, potentially reversing trends of increasing air pollution concentrations and mortality in Africa and South, West, and Central Asia. These projected benefits are independent of carbon dioxide mitigation measures. Benefits of BC measures are underestimated because we did not account for benefits from reduced indoor exposures and because outdoor exposure estimates were limited by model spatial resolution.

EDGAR v4.3.2 Global Atlas of the three major GreenhouseGas Emissions for the period 1970–2012

As a reference work on compilation, monitoring and verification of emission inventories on global scale, this book provides emission inventory scientists with a comprehensive literature overview. Moreover anybody can download it free of charge fromwww.nap.edu/catalog.php?record_id=12883. A prerequisite for an international assessment of greenhouse gas (GHG) emission inventories is a list of clear definitions, for which this report chose the UNFCCC standard terms and summarized them in a clarifying box in the introductory chapter. Not only methods but also uncertainties are addressed with an exhaustive list of references. This book can significantly contribute to re-assess the scientific robustness behind the UNFCCC rules for emission inventorying, as they are applied by the roster experts reviewing the national reports. To each of the relevant GHG emission inventory topics a separate chapter is dedicated: (i) national inventory reports, (ii) land-use sources/sinks fluxes and (iii) atmospheric and oceanic measurements and inverse modelling. All three chapters describe the technical/scientific details for GHG emissions inventory assessments concisely and provide references for the reader to allow further investigation. Chapter 2 on national inventory reports familiarizes the reader with the framework and current practices for developing the National Inventories/Communications of GHG emissions. International sector-specific reporting is synthesized such that it presents an overview on the contribution of each sector and on the lead of data gathering institutions and research centres. Often the national systems behind GHG inventories are not fully appreciated because the efforts improving accuracy and decreasing uncertainty are overshadowed by problems of consistency and the 1990 global base year. An overlooked issue is the generally low comparability of national estimates caused by the unharmonized use of different methods and proxy definitions. The report tends to underestimate the potential for reporting with default data for non Annex I countries in the short term. Instead, near-term measures that should be taken as capacity building in developing countries including associated costs, further extension of independent verification of ‘self-reported’ emissions data, as well as assessment and means to reduce the uncertainties are highlighted. Recommendations are given mainly on extending the inventory reporting and reviewing to all UNFCCC parties, on improving methods and on facilitating cross-comparisons of ‘self-reported’ data with data derived from other monitoring sources. Support to IPCC, UN, IEA and FAO to improve their statistics is thereby underlined. Chapter 3 addresses agriculture, land use and forestry activities, focusing mainly on the situation in the USA, and does not assess the experience achieved by other Annex I parties or international organizations to address also global land cover changes. The method proposed of combined statistical sampling and remote sensing seems indeed the most appropriate for LULUCF GHG inventories on land remaining in the same category, but more might be needed for detecting conversions. Relatively large uncertainties (above 10% to be realistic) and difficulties in reporting small pools are to be anticipated. Harmonization opportunities (of definitions, and computational methods) could have been pointed out as a great potential to achieve a complete and consistent global dataset. The list of international efforts could include not only the NASA-sponsored FluxNet network, but also the EU FP6 and FP7 research projects such as NitroEurope and CarboEurope on the nitrogen and carbon cycles. Chapter 4 provides an overview of the potential and limitations of using atmospheric measurements and inverse modelling for verification of ‘self-reported’ (‘bottom-up’) emission inventories. This chapter focuses mainly on CO2, which is clearly the most important anthropogenic GHG but at the same time probably the most difficult one for verification by

Impact of intercontinental pollution transport on North American ozone air pollution: an HTAP phase 2 multi-model study

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 1,287 tonnes in 2008. Specifically, gaseous elemental mercury (GEM) (Hg(0)) accounted for 72% of the global total emissions, while gaseous oxidised mercury (GOM) (Hg(2+)) and particle bound mercury (PBM) (Hg-P) accounted for only 22% and 6%, respectively. The less reactive form, i.e., Hg(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(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.

Climate and air quality impacts of combined climate change and air pollution policy scenarios

We present an overview of the coordinated global numerical modelling experiments performed during 2012–2016 by the Task Force on Hemispheric Transport of Air Pollution (TF HTAP), the regional experiments by the Air Quality Model Evaluation International Initiative (AQMEII) over Europe and North America, and the Model Intercomparison Study for Asia (MICS-Asia). To improve model estimates of the impacts of intercontinental transport of air pollution on climate, ecosystems, and human health and to answer a set of policy-relevant questions, these three initiatives performed emission perturbation modelling experiments consistent across the global, hemispheric, and continental/regional scales. In all three initiatives, model results are extensively compared against monitoring data for a range of variables (meteorological, trace gas concentrations, and aerosol mass and composition) from different measurement platforms (ground measurements, vertical profiles, airborne measurements) collected from a number of sources. Approximately 10 to 25 modelling groups have contributed to each initiative, and model results have been managed centrally through three data hubs maintained by each initiative. Given the organizational complexity of bringing together these three initiatives to address a common set of policy-relevant questions, this publication provides the motivation for the modelling activity, the rationale for specific choices made in the model experiments, and an overview of the organizational structures for both the modelling and the measurements used and analysed in a number of modelling studies in this special issue.

A new global anthropogenic SO 2 emission inventory for the last decade: A mosaic of satellite-derived and bottom-up emissions

The Emissions Database for Global Atmospheric Research (EDGAR) compiles anthropogenic emissions data for greenhouse gases (GHGs), and for multiple air pollutants, based on international statistics and emission factors. EDGAR data provide quantitative support for atmospheric modelling and for mitigation scenario and impact assessment analyses as well as for policy evaluation. The new version (v4.3.2) of the EDGAR emission inventory provides global estimates, broken down to IPCC-relevant source-sector levels, from 1970 (the year of the European Union’s first Air Quality Directive) to 2012 (the end year of the first commitment period of the Kyoto Protocol, KP). Strengths of EDGAR v4.3.2 include global geo-coverage (226 countries), continuity in time, and comprehensiveness in activities. Emissions of multiple chemical compounds, GHGs as well as air pollutants, from relevant sources (fossil fuel activities but also, for example, fermentation processes in agricultural activities) are compiled following a bottom-up (BU), transparent and IPCC-compliant methodology. This paper describes EDGAR v4.3.2 developments with respect to three major long-lived GHGs (CO2, CH4, and N2O) derived from a wide range of human activities apart from the land-use, land-use change and forestry (LULUCF) sector and apart from savannah burning; a companion paper quantifies and discusses emissions of air pollutants. Detailed information is included for each of the IPCC-relevant source sectors, leading to global totals for 2010 (in the middle of the first KP commitment period) (with a 95 % confidence interval in parentheses): 33.6(±5.9) Pg CO2 yr−1, 0.34(±0.16) Pg CH4 yr−1, and 7.2(±3.7) Tg N2O yr−1. We provide uncertainty factors in emissions data for the different GHGs and for three different groups of countries: OECD countries of 1990, countries with economies in transition in 1990, and the remaining countries in development (the UNFCCC nonAnnex I parties). We document trends for the major emitting countries together with the European Union in more Published by Copernicus Publications. 960 G. Janssens-Maenhout et al.: EDGAR greenhouse gas emissions detail, demonstrating that effects of fuel markets and financial instability have had greater impacts on GHG trends than effects of income or population. These data (https://doi.org/10.5281/zenodo.2658138, Janssens-Maenhout et al., 2019) are visualised with annual and monthly global emissions grid maps of 0.1× 0.1 for each source sector. 1 Historical evolution An essential component of the UN Framework Convention on Climate Change (UNFCCC, 1992) is the collection of nationally reported inventories and information on these greenhouse gas (GHG) emission inventory time series. At the time the UNFCCC was established, the 24 members of the OECD in 1990 and 16 other European countries and Russia were considered liable for “the largest share of historical and current global emissions of GHG” and taken up in Annex I to the UNFCCC. These Annex I countries and the European Union1 submit annually complete inventories of GHG emissions from the 1990 base year2 until the latest year for which full accounting is completed and reviewed (typically with a 2-year time lag), and these inventories are all reviewed to ensure transparency, completeness, comparability, consistency and accuracy3. This allows for most of these Annex I countries to track progress towards their reduction targets committed under the Kyoto Protocol (UNFCCC, 1997). Other (non-Annex I) countries are encouraged to submit their GHG inventories as part of their National Communications and Biennial Update Reports (BURs). The GHG inventories of nonAnnex I countries were required to cover CO2, CH4 and N2O emissions for 1 year (1990 or 1994), without specific documentation and only subject to a brief review. However, the Paris Agreement (UNFCCC, 2015) requires submission every 2 years of BURs4, which are subject to international consultation and analysis. Theoretically, UNFCCC should receive at the latest after 2 years national emissions inventories from each of the 197 countries, but as shown in Fig. 1a, not all countries did provide a national inventory and 154 countries did not provide a completed (i.e. year-2) time se1This includes the 28 Member States of the European Union (EU) as of 1 July 2013. 2For some economies in transition, another year such as 1988 or 1989 can be chosen under UNFCCC as the base year. These GHG emissions are mainly sources, but also include carbon stock sinks for which the human-induced part needs to be assessed with care (Grassi et al., 2018). 3These five principles of a good reporting practice are defined in the UNFCCC guidelines for national GHG inventory, e.g. https://pdfs.semanticscholar.org/3c30/ a1bd769dee5299746e0af825c7ab4ed55fba.pdf. EDGAR uses the term “comprehensiveness” to summarise these principles. 4The first BUR submitted should cover the inventory for the year no more than 4 years prior to the submission data, and subsequent BURs should be submitted every 2 years, but flexibility is given to the least developed countries and small island developing states. ries of inventories. In addition, many countries lack a welldeveloped statistical infrastructure, which is needed for an accurate bottom-up (BU) inventory. Figure 1b presents the latest year that is covered with a national inventory, with dates for quite a few countries more than 10 years ago: for most South-East Asian countries this is between 2004 and 2007 and for most African countries between 2000 and 2003. As such, the collection of national reports/communications does not provide a complete, consistent and comparable global dataset which can be used to understand the global budgets of the most important GHG emissions and their impact on climate. Very few bottom-up inventories of global anthropogenic emissions have been produced with continued effort for more than 2 decades. The Carbon Dioxide Information Analysis Centre (CDIAC) (Boden et al., 2017; Andres et al., 2014) and the Emissions Database for Global Atmospheric Research (EDGAR) (Olivier and Janssens-Maenhout, 2016; Olivier et al., 2016) provide global totals, whereas the IEA provides CO2 estimates from fuel combustion only and the FAO CH4 from agriculture only. While CDIAC ceased operation in September 2017, the Open-source Data Inventory for Anthropogenic CO2 (ODIAC) (Oda et al., 2018) continued to use the CDIAC data and combined these with geospatial proxies (including night light satellite maps) to provide CO2 grid maps, as EDGAR is also doing (using other geospatial proxies). In addition, the new Community Emissions Data System (CEDS) of Hoesly et al. (2018) builds upon existing inventories to provide a new gridded dataset of all emission species for the Climate Model Inter-comparison Programme CMIP6. The scientific community started to bring together these anthropogenic BU emissions with top-down estimates covering also the natural component to obtain the Global Carbon Budget (GCB) (Le Quéré et al., 2018) and the Global Methane Budget (Saunois et al., 2016). These budgets are important input for the periodic global stocktake that the Paris Agreement envisages from 2023 onwards (with the submitted inventories for 2021). Even though significant progress in inventory compilation has been made, the overall uncertainty of the global total has become larger over time because the share of emissions from non-Annex I countries (with less developed statistical infrastructure) increased from less than 40 % in 1990 to more than 60 % in 2012, as shown in Fig. 2. To support both science and policy making with the monitoring and verification of the GHG emissions, it is important Earth Syst. Sci. Data, 11, 959–1002, 2019 www.earth-syst-sci-data.net/11/959/2019/ G. Janssens-Maenhout et al.: EDGAR greenhouse gas emissions 961 Figure 1. (a) Inventory submission as received at UNFCCC (by January 2017) for all countries: expressed with the year of emission reporting in which the latest national communication to UNFCCC took place. (b) Inventory submission as received at UNFCCC (by January 2017) for all countries expressed with the latest year of emission that is covered in the inventory submitted to UNFCCC. Figure 2. Relative contribution of the Annex I and non-Annex I countries to the global total GHG emissions. The red, brown and orange dashed parts of the stack correspond to the non-Annex I share that increases from about 1/3 in 1990 to almost 2/3 in 2012. www.earth-syst-sci-data.net/11/959/2019/ Earth Syst. Sci. Data, 11, 959–1002, 2019 962 G. Janssens-Maenhout et al.: EDGAR greenhouse gas emissions that emissions are estimated by using comparable methodologies, consistent source allocation and comprehensive coverage of the globe. The EDGAR v4.3.2 global inventory illustrates the result of a bottom-up technology-based compilation of countryand sector-specific emission time series for 1970–2012. Furthermore, the monthly resolution and global grid maps at a spatial resolution of 0.1× 0.1 allow direct use in atmospheric models as well as in analyses of policy impacts. The first version of the Emissions Database for Global Atmospheric Research (EDGAR v2) answered the needs of the air quality community to map technological parameters of air pollution sources and was published by Olivier et al. (1996). Since then, several updated versions (Olivier, 2002) have been released (EDGAR-HYDE, EDGAR v3.2, EDGAR 3.2 FT2000). Driven by the development of scientific knowledge on emission generating processes and by the availability of more recent information, the EDGAR v4 datasets were constructed including new emission factors and additional end-of-pipe abatement measures. The specification of the combustion technology and its endof-pipe abatement is more important for air pollutants and aerosols than for GHGs. CO2 combustion emissions are fueldetermined and carbon capture and storage are not yet implemented at an opera

Estimation of shipping emissions using vessel Long Range Identification and Tracking data

The recent update on the US National Ambient Air Quality Standards (NAAQS) of the ground-level ozone (O3/ can benefit from a better understanding of its source contributions in different US regions during recent years. In the Hemispheric Transport of Air Pollution experiment phase 1 (HTAP1), various global models were used to determine the O3 source–receptor (SR) relationships among three continents in the Northern Hemisphere in 2001. In support of the HTAP phase 2 (HTAP2) experiment that studies more recent years and involves higher-resolution global models and regional models’ participation, we conduct a number of regional-scale Sulfur Transport and dEposition Model (STEM) air quality base and sensitivity simulations over North America during May–June 2010. STEM’s top and lateral chemical boundary conditions were downscaled from three global chemical transport models’ (i.e., GEOS-Chem, RAQMS, and ECMWF C-IFS) base and sensitivity simulations in which the East Asian (EAS) anthropogenic emissions were reduced by 20 %. The mean differences between STEM surface O3 sensitivities to the emission changes and its corresponding boundary condition model’s are smaller than those among its boundary condition models, in terms of the regional/period-mean (<10 %) and the spatial distributions. An additional STEM simulation was performed in which the boundary conditions were downscaled from a RAQMS (Realtime Air Quality Modeling System) simulation without EAS anthropogenic emissions. The scalability of O3 sensitivities to the size of the emission perturbation is spatially varying, and the full (i.e., based on a 100% emission reduction) source contribution obtained from linearly scaling the North American mean O3 sensitivities to a 20% reduction in the EAS anthropogenic emissions may be underestimated by at least 10 %. The three boundary condition models’ mean O3 sensitivities to the 20% EAS emission perturbations are ~8% (May–June 2010)/~11% (2010 annual) lower than those estimated by eight global models, and the multi-model ensemble estimates are higher than the HTAP1 reported 2001 conditions. GEOS-Chem sensitivities indicate that the EAS anthropogenic NOx emissions matter more than the other EAS O3 precursors to the North American O3, qualitatively consistent with previous adjoint sensitivity calculations. In addition to the analyses on large spatial–temporal scales relative to the HTAP1, we also show results on subcontinental and event scales that are more relevant to the US air quality management. The EAS pollution impacts are weaker during observed O3 exceedances than on all days in most US regions except over some high-terrain western US rural/remote areas. Satellite O3 (TES, JPL–IASI, and AIRS) and carbon monoxide (TES and AIRS) products, along with surface measurements and model calculations, show that during certain episodes stratospheric O3 intrusions and the transported EAS pollution influenced O3 in the western and the eastern US differently. Free-running (i.e., without chemical data assimilation) global models underpredicted the transported background O3 during these episodes, posing difficulties for STEM to accurately simulate the surface O3 and its source contribution. Although we effectively improved the modeled O3 by incorporating satellite O3 (OMI and MLS) and evaluated the quality of the HTAP2 emission inventory with the Royal Netherlands Meteorological Institute–Ozone Monitoring Instrument (KNMI–OMI) nitrogen dioxide, using observations to evaluate and improve O3 source attribution still remains to be further explored.