U.S. National Black Carbon and Methane Emissions a Report to the Arctic Council

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U.S. NATIONAL BLACK CARBON AND METHANE EMISSIONS A REPORT TO THE ARCTIC COUNCIL

AUGUST 2015

U.S. NATIONAL BLACK CARBON AND METHANE EMISSIONS A REPORT TO THE ARCTIC COUNCIL

AUGUST 2015

TABLE OF CONTENTS

EXECUTIVE SUMMARY...... 1

ABOUT THIS REPORT...... 1

SUMMARY OF CURRENT BLACK CARBON EMISSIONS AND FUTURE PROJECTIONS . 2

SUMMARY OF CURRENT METHANE EMISSIONS AND FUTURE PROJECTIONS...... 4

SUMMARY OF NATIONAL MITIGATION ACTIONS BY POLLUTANT AND SECTOR . 6 BLACK CARBON. 6 METHANE . 11

HIGHLIGHTS OF BEST PRACTICES AND LESSONS LEARNED FOR KEY SECTORS. 16 TRANSPORT/MOBILE. 16 OPEN BIOMASS BURNING (INCLUDING WILDFIRES). 16 RESIDENTIAL/DOMESTIC ...... 17 OIL & NATURAL GAS...... 17 OTHER . 17

PROJECTS RELEVANT FOR THE ARCTIC...... 18 ARCTIC AIR QUALITY IMPACT ASSESSMENT MODELING...... 18 BLACK CARBON DEPOSITION ON U.S. SNOW PACK ...... 18 EMISSIONS AND TRANSPORT FROM AGRICULTURAL BURNING AND FOREST FIRES ...... 18 MEASUREMENT OF BLACK CARBON AND METHANE IN THE ARCTIC...... 18 MEASUREMENT OF MARITIME BLACK CARBON EMISSIONS AND DIESEL FUEL ALTERNATIVES...... 18 REDUCTION OF BLACK CARBON IN THE RUSSIAN ARCTIC...... 19 VALDAY CLUSTER UPGRADE FOR BLACK CARBON REDUCTION IN THE REPUBLIC OF KARELIA, RUSSIAN FEDERATION. . . . . 19 AVIATION CLIMATE CHANGE RESEARCH INITIATIVE...... 20 TRACKING SOURCES OF BLACK CARBON IN THE ARCTIC. 20

OTHER INFORMATION...... 20

APPENDIX 1: U.S. BLACK CARBON EMISSIONS . 22

APPENDIX 2: U.S. METHANE EMISSIONS (MMT CO2E), 1990–2013 ...... 24

EXECUTIVE SUMMARY

U.S. black carbon emissions are declining and additional reductions are expected, largely through strategies to reduce the emissions from mobile diesel engines that account for roughly 40 percent of the U.S. total. A number of fine particulate

matter (PM2.5) control strategies have proven successful in reducing black carbon emissions from mobile sources. The two principal strategies include: (1) emissions standards for new vehicles and engines, with emissions reductions occurring as the vehicle and engine fleet turns over, and (2) controls or strategies that reduce emissions from existing in-use engines, such as diesel retrofits. It is important to note that these strategies are complementary, and can be employed simultaneously. Mitigation opportunities are more limited in other sectors such as open burning (which accounts for 39 percent), either due to the low level of remaining controllable emissions or the lack of effective black carbon controls, particularly when considering co-emissions of organic carbon and other cooling particles. Regulations and other activities that reduce emissions of fine particulate matter (of which black carbon is a component), however, may achieve additional reductions of black carbon. Reductions in black carbon, particularly north of the 40th parallel, can help to mitigate warming in the Arctic specifically by reducing deposition on snow and ice and will also lead to potentially significant health benefits. For methane, a combination of voluntary and regulatory measures are reducing emissions from several sectors, most notably the oil and natural gas sector and municipal landfills (which respectively accounted for about 29 percent and 18 percent of total U.S. methane emissions in 2013). In March 2014, the United States issued “A Strategy to Reduce Methane Emissions” to achieve further reductions. This Strategy highlights both new and existing programs aimed at reducing domestic and international methane emissions through incentive-based programs. It also promotes research and development efforts to improve methane emissions measurement and to advance methane reduction technologies. The strategy focuses on key sectors including landfills, coal mines, agriculture, and oil and natural gas and highlights examples of technologies and industry-led best practices that are helping cut methane emissions. In January 2015, the United States announced a goal of reducing methane emissions from the oil and natural gas sector by 40–45 percent from 2012 levels by 2025, together with a strategy for achieving such reductions. Reducing methane emissions from the other major source, agriculture (approximately 37 percent of 2013 emissions), is generally more challenging though some opportunities do exist, particularly with regard to manure management. Regardless of where emitted, methane contributes to the elevated concentrations of greenhouse gases in the atmosphere. Accordingly, mitigation measures implemented throughout the United States will help reduce the pace of warming in the Arctic and around the globe.

ABOUT THIS REPORT

Under the Enhanced Black Carbon and Methane Emissions Arctic Council Framework for Action,1 the eight Arctic Nations— including the United States—agreed to develop biennial national reports that summarize their emissions of black carbon and methane. These reports, based respectively on prior submissions under the Convention on Long-Range Transboundary Air Pollution and the United Nations Framework Convention on Climate Change, are requested also to include emission- reduction actions, highlights of best practices and lessons learned, and projects relevant for the Arctic, with other information as relevant. The United States submits this document to the Secretariat of the Arctic Council pursuant to these provisions of the Framework.

1 https://oaarchive.arctic-council.org/handle/11374/610. The eight Arctic states, which together comprise the Arctic Council, are: Canada, Den- mark, Finland, Iceland, Norway, Russia, Sweden, and the United States. U.S. NATIONAL BLACK CARBON AND METHANE EMISSIONS

Figure 1. U.S. Black Carbon Emissions in 2011 (0.51 million metric tons) Source: U.S. EPA 2011 National Emission Inventory Modeling Platform (2011v6.1)

SUMMARY OF CURRENT BLACK CARBON EMISSIONS AND FUTURE PROJECTIONS

In March 2015, the United States (U.S.) submitted emission Monitoring and Assessment Program working group’s 2011 inventory data, including data for black carbon, under the report entitled The Impact of Black Carbon on Arctic Climate5 Convention on Long-Range Transboundary Air Pollution (recommendation 10.2), found there is not enough known (CLRTAP).2 Black carbon accounts for approximately 11 about the emissions and effects of black carbon from flaring percent of U.S. fine particle emissions.3 As shown in Figure 1, and that better inventories, analysis, and studies are needed. mobile sources and open burning contribute the majority of Figure 2 shows projected black carbon emissions by sector U.S. black carbon emissions. Detailed emission information in 2011, 2018, and 2025. U.S. black carbon emissions have can be found in the appendix to this report. been declining and additional reductions are expected, largely Globally, the largest black carbon emission sources in Arctic through strategies to reduce emissions of fine particulate

nations are forest burning and wildfires, and on‐road diesel matter (PM2.5) from mobile diesel engines. Key strategies vehicles, followed by residential burning, off‐road diesel and include: (1) more stringent emissions standards for new stationary diesel engines, agricultural burning, and industrial vehicles and engines, with emissions reductions occurring combustion. Gas flaring may currently be a significant as the vehicle and engine fleet are replaced with new models, source as well, with a significant share occurring at high and (2) controls or strategies that reduce emissions from latitudes. The Arctic Council Task Force on Short-lived existing in-use engines, such as diesel retrofits. It is important Climate Forcers4 (2013 recommendation 9) and the Arctic to note that these strategies are complementary, and can be employed simultaneously.6

2 The U.S. CLRTAP submission can be accessed at: http://www.ceip. Other U.S. source categories have more limited mitigation at/ms/ceip_home1/ceip_home/status_reporting/2015_submissions/ potential either due to the low level of remaining controllable 3 Source: U.S. EPA 2011 National Emission Inventory Modeling

Platform v6. Fine particles (PM2.5), which are 2.5 micrometers in diameter or smaller, are produced from all types of combustion, 5 http://www.amap.no/documents/doc/the-impact-of-black-carbon- including motor vehicles, power plants, residential wood burning, on-arctic-climate/746 forest fires, agricultural burning, and some industrial processes. 6 Please note that more detailed information can be found in the U.S.

Black carbon is a component of PM2.5. Environmental Protection Agency’s 2012 Report to Congress on 4 http://www.arctic-council.org/index.php/en/document-archive/cate- Black Carbon: http://www.epa.gov/blackcarbon/2012report/fullre- gory/447-slcf-tf port.pdf

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Figure 2. Projected Changes in U.S. Black Carbon Emissions by sector: 2011, 2018, and 2025. Source: U.S. EPA 2011 National Emission Inventory Modeling Platform (2011v6.1) Note: The inventory projections are based on the National Emission Inventory Modeling Platform (2011v6.1), while the CLRTAP inventory was based on the previous modeling platform (2011v6). Slight differences between these platforms will result in small variations in emission values, but do not substantially change the conclusions presented. No data are displayed for open biomass burning because future projections are not made for this sector.

emissions (e.g., stationary industrial and energy sources) 40th parallel were responsible for approximately 38 percent or the lack of effective black carbon controls, particularly of U.S. black carbon emissions. Table 1 shows the estimated when considering co-emissions of organic carbon and other magnitude and proportion of emissions located above the 40th cooling particles (e.g., residential wood combustion and parallel by sector. As in the United States as a whole, mobile open biomass burning). sources account for 40 percent of black carbon emissions th As noted in the U.S. EPA’s 2012 Report to Congress on north of the 40 parallel. As a result, expected reductions in Black Carbon, emissions of black carbon north of the 40th this sector are important for mitigating the climate impacts parallel are thought to be particularly important for black of black carbon in the Arctic. carbon climate-related effects in the Arctic. In 2011, the 25 states located with half or more of their area north of the

Emissions North of 40th Parallel % of Total Emissions Sector (metric tons) North of 40th Parallel Transport/Mobile 84,000 43% Open Biomass Burning 64,000 32% Other 18,000 9% Residential Combustion 14,000 7% Industry 14,000 6% Energy/Power 5,800 2% Total 197,000 Table 1. U.S. Black Carbon Emissions in States North of 40th Parallel. Source: U.S. EPA 2011 National Emission Inventory Modeling Platform (2011v6.1) Note: All totals rounded to two significant digits Note: Inventory data presented here are based on the National Emission Inventory modeling platform (2011v6.1), while the CLRTAP inventory was based on the previous modeling platform (2011v6). Slight differences between these platforms will result in small variations in emission values, but do not substantially change the conclusions presented.

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SUMMARY OF CURRENT METHANE EMISSIONS AND FUTURE PROJECTIONS

Note: Includes anthropogenic sources of methane emissions only. Detailed emission information can be found in the appendix Under the Arctic Council Framework, countries are asked to this report. to submit summaries of methane emissions reported under Enteric fermentation was the largest anthropogenic source the United Nations Framework Convention on Climate of methane emissions in the U.S. in 2013, with emissions Change (UNFCCC). The U.S.’s most recent submission 0.2 percent larger than in 1990. Natural gas systems were the to the UNFCCC is the 2015 Inventory of U.S. Emissions second largest anthropogenic source in 2013, with emissions and Sinks: 1990–2013.7 Values reported reflect a revised decreasing 12 percent since 1990. The decrease in methane 100-year time horizon global warming potential (GWP) for emissions is largely due to the decrease in emissions from methane of 25, as presented in the IPCC AR4, following production and distribution. The decrease in production updated UNFCCC reporting guidelines.8 emissions is due to the requirements of the 2012 New Source In 2013, methane was responsible for about 10 percent of Performance Standards (NSPS) for oil and gas, and from a U.S. greenhouse gas emissions, totaling 636.3 million metric variety of voluntary reduction activities.

tons (MMT) CO2 equivalents (CO2e). Six sectors account for Landfills were the third largest anthropogenic source of U.S. 92 percent of these emissions: enteric fermentation (animal methane emissions and showed a 38 percent decrease from digestive tract gas), natural gas systems, landfills, coal mining, 1990 to 2013. This decline can be attributed to a reduction manure management, and petroleum (oil) systems. Between in the amount of decomposable materials placed in municipal 1990 and 2013, total domestic methane emissions decreased solid waste landfills and an increase in the amount of landfill by 15 percent, due largely to measurable reductions from gas (a large proportion of which is methane) collected and landfills, natural gas systems, and coal mining. Figure 3 combusted. Coal mine methane emissions were the next shows U.S. methane emissions by sector for selected years. largest source and showed a 33 percent decrease over the record period. 7 Data is published online at: http://www.epa.gov/climatechange/ Methane emissions from manure management increased by ghgemissions/usinventoryreport.html 65 percent since 1990. The majority of this increase was from 8 http://unfccc.int/resource/docs/2013/cop19/eng/10a03.pdf#page=2

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Figure 3. U.S. Methane Emissions by Sector, 1990–2013. Source: EPA Greenhouse Gas Inventory Report 1990–2013, published 2015

Source 2015 2020 2025 2030

Enteric Fermentation 161 175 180 187 Natural Gas 157 167 180 187 Landfills 121 120 118 115 Coal Mines 75 77 80 82 Manure Management 62 63 64 65 Other 113 112 114 108 Total 688 713 737 745 Table 2. Projected U.S. Methane Emissions (MMT CO2e), 2015–2030. Source: 2014 Climate Action Report, Table 5-2, Updated to AR4 GWPs. See note in text regarding subsequent developments affecting these projections.

swine and dairy farms, since the general trend in manure by the White House in March 2014 (see discussion on page management is one of increasing use of liquid systems, 11).9 The U.S. Methane Strategy outlines a suite of actions which tend to produce greater methane emissions. Finally, (some already taken) intended to significantly mitigate emissions from petroleum systems decreased by 20 percent methane emissions from these sources. Based on current during the study period, mainly due to domestic voluntary and planned activities under the U.S. Methane Strategy, we reductions programs. expect actual future emissions to be lower than the projections Projected methane emissions from 2015–2030 are shown in presented here as a result of these, and other, actions. Table 2 (as reported in the 2014 Climate Action Report). In response to these anticipated increases in methane emissions from various sources and sectors, “A Strategy to Reduce Methane Emissions” (the U.S. Methane Strategy) was issued 9 https://www.whitehouse.gov/sites/default/files/strategy_to_reduce_ methane_emissions_2014-03-28_final.pdf

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SUMMARY OF NATIONAL MITIGATION ACTIONS BY POLLUTANT AND SECTOR

carbon emissions from diesel engines is the catalyzed diesel BLACK CARBON particulate filter (DPF). Because DPFs are made inoperable Black carbon is not the direct target of existing regulatory by fuels with high sulfur content, mitigation of mobile programs in the United States, but it has been reduced through source black carbon emissions depends on the availability controls aimed at reducing ambient PM concentrations 2.5 and widespread use of low-sulfur fuels. In the United States, or direct particle emissions. Analysis of relevant regulatory regulations require the use of ultra-low sulfur diesel (ULSD) programs suggests that available control technologies and fuel (15 ppm sulfur) in diesel engines. For more detailed approaches are projected to continue to reduce black carbon information on topics presented in this section, please refer emissions from many key source categories at reasonable to Chapter 8 and Appendices 4–6 of the Report to Congress cost. In addition to the climate benefits of reducing black on Black Carbon (U.S. EPA, March 2012).10 carbon, particularly in northern parts of the United States, these reductions will result in substantial health benefits New Engine Standards through reductions in PM2.5. In the United States, stringent PM emissions standards for new mobile source engines are being phased in across Transport/Mobile different sectors between 2007 and 2020. The costs and A number of PM2.5 control strategies have proven successful benefits for many of these regulations are shown in Table in reducing black carbon emissions from mobile sources. The 2. In most cases, the most stringent standards result in the two principal strategies include: (1) emissions standards for use of DPFs on new engines. new vehicles and engines, with emissions reductions occurring as the vehicle and engine fleet turns over, and (2) controls The main source of diesel PM has traditionally been heavy- or strategies that reduce emissions from existing in-use duty on-highway diesel trucks with gross vehicle weights from engines, such as diesel retrofits. It is important to note that 8,501 to 80,000 lbs. The first standards controlling diesel PM these strategies are complementary, and can be employed simultaneously. The main technology for reducing black 10 http://www.epa.gov/blackcarbon/2012report/fullreport.pdf

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Total Monetized Benefits Rule Total Cost (billion USD) (billion USD) Benefit/Cost Ratio Heavy Duty Diesel 2007 $6.1 $94 15 Nonroad Diesel Tier 4 $2.9 $110 40 Locomotive/ Marine $0.8 $13 16 C3 Ocean Going Vessel $3.6 $130 36 Light Duty Tier 2 $7.8 $37 4.7 Light Duty Tier 3 $1.6 $9.7 6.1 Total $23 $400 17 Table 3. 2030 Annual Benefits and Costs for Six Major Mobile Source Rules (2014$) Note: Numbers drawn from respective Regulatory Impact Analyses. Values have been adjusted from the year in which they were presented to common year 2014 dollars. Values rounded to two digits; totals may not sum due to rounding.

for onroad engines were standards for visible smoke (which to those used in construction/farm equipment (less than has some correlation with PM) effective with the 1970 model 5 liters/cylinder or for some categories less than 7 liters/ year followed by increasingly stringent PM mass standards cylinder). C2 marine engines (between 5 or 7 and 30 liters/ starting with the 1988 model year. For the 2007 vehicle cylinder) are similar in size to locomotive diesels, while C3 (engine) model year, stringent emission standards of 0.01 engines (greater than 30 liters/cylinder), used in ocean-going g/BHP-hr (grams per brake horsepower/hour—a standard vessels, are similar in size to those used in some power plants. unit for emissions from heavy-duty mobile source engines) The most recent set of emission standards began phasing became effective for heavy-duty on-highway diesel engines, in for these engines in 2014 and will likely result in most which represents over 99% control from a pre-control diesel new C1 and C2 commercial marine engines having DPFs. engine in the 1970 time frame. To meet these PM standards, Implementing these changes will result in a dramatic drop virtually all new on-highway diesel trucks in the United States, in PM emissions and an even more dramatic drop in black beginning with the 2007 model year, have been equipped with carbon emissions from these engines. As in locomotives, older DPFs. These standards are resulting in dramatic reductions marine diesel engines must be certified to more stringent in PM and black carbon from the vehicle sector. emission standards upon remanufacturing, compared to The U.S. EPA’s first PM emission standards for nonroad diesel their previous certification level. engines11 began in 1996 and the Tier 4 nonroad standards For U.S. passenger cars and light-duty trucks, national PM developed in 2004 are now completely phased in. The U.S. emissions standards of 0.01 g/mile (known as Tier 2 standards) EPA has also implemented several tiers of PM emission took effect during 2004–2006. National PM emission standards for locomotive engines, with the most recent set of standards of 0.003 g/mile (known as Tier 3 standards) will standards to be effective in 2015. These newest standards take effect for U.S. passenger cars (and light-duty trucks) will likely result in the use of DPFs on new locomotives. during the 2017–2025 timeframe. These standards apply to In addition, national emission standards require that older both gasoline and diesel light-duty vehicles, although there locomotives that are remanufactured must be certified to more are relatively few diesel passenger cars in the United States. stringent emission standards than their prior certification The U.S. Department of Transportation (DOT) and the level. U.S. EPA have issued light-duty vehicle fuel economy and Commercial marine vessels are classified as C1, C2, or C3 tailpipe greenhouse gas standards effective through the 2022 based on engine size. C1 marine engines are similar in size and 2025 model years, respectively. The U.S. DOT and U.S. EPA have also issued heavy-duty vehicle fuel economy standards for 2014–2018 model years and have proposed 11 The emission standards for nonroad diesel engines referenced Phase II standards for heavy-duty vehicles, which would be here apply to diesel engines used in most construction, agri- effective through 2027. cultural, industrial and airport equipment.

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Mitigation Approaches for In-use Mobile Sources in Alaska and other northern states can also provide the benefit of reducing the black carbon contribution to Arctic The National Clean Diesel Campaign and the SmartWay warming. In addition, DERA projects are estimated to Transport Partnership Program are the U.S. EPA’s two reduce approximately 4.4 MMT CO2 during the lifetime of primary programs responsible for reducing emissions from the affected engines, resulting in substantial climate benefits in-use diesel vehicles and equipment. These programs support and saving more than 431 million gallons of fuel due to idle the testing and deployment of numerous technologies and reduction and more fuel-efficient technologies. strategies to reduce emissions, including black carbon, from in-use diesel engines and can provide immediate reductions. In 2004, the U.S. EPA launched its SmartWay Transport Partnership. SmartWay is an innovative, voluntary partnership Despite the implementation of the emissions standards between the U.S. EPA and private industry to reduce outlined in the previous section, approximately 10–11 fuel use and emissions from goods transport. SmartWay million older diesel engines—ones manufactured before the promotes fuel-saving and emission control technologies; recent standards took effect—remain in use. The National some technologies—such as idle reduction or newer truck Clean Diesel Campaign addresses these older engines chiefly replacements—do both. Because most cargo-hauling large through clean diesel grants to eligible entities such as regional, trucks, locomotives, barges, and other freight vehicles use state, local or tribal agencies/consortia, port authorities, or diesel fuel, and these vehicles remain in the legacy fleet nonprofit organizations. The U.S. EPA began awarding for decades, reducing fuel use and emissions from goods such grants in 2008 under the Diesel Emissions Reduction movement and the legacy fleet can have a major impact on Act (DERA), a grant program created by Congress as part diesel emissions, including emissions of black carbon. of the Energy Policy Act of 2005 to reduce diesel emissions from these older engines. DERA projects provide immediate More than 3,000 companies, both large and small, participate black carbon reductions by reducing PM emissions from the in SmartWay. To date, these SmartWay partners have saved legacy fleet of diesel engines. EPA has awarded more than $20.6 billion dollars by cutting their fuel use by 144.3 million 640 grants since the start of DERA in 2008 through FY barrels of oil. This has in turn led to reductions of 39,000 2013. These grants have retrofitted, repowered (replaced the metric tons of PM. In addition, SmartWay partners saved 61.7 engine), upgraded or replaced more than 73,000 vehicles or MMT CO2 since 2004. Improving supply chain efficiency pieces of equipment. also helps these companies grow the economy, protect and generate jobs, cut imports of foreign oil, contribute to U.S. EPA estimates that total lifetime emission reductions achieved energy security, and be good environmental stewards. through DERA funding include 13,400 metric tons of PM. These reductions are estimated to result in up to $12.6 billion In addition to the U.S. EPA programs, the DOT has several of health benefits nationally. Local diesel emissions reductions programs that help to reduce transportation emissions. These include funding for projects that reduce air emissions of

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criteria pollutants, such as PM, through the Congestion to wildfire. All of the strategies will help the United States Mitigation and Air Quality Program, as well as DOT’s overall to move effectively to reduce wildfire emissions. efforts to improve system efficiency, strengthen transportation planning, and encourage low emissions transportation The USDA Natural Resources Conservation Service (NRCS) choices. As explained above, controls to address PM from provides direct technical and financial assistance for prescribed mobile sources will also reduce black carbon, resulting in burning on nearly one-half million acres of private land each substantial climate and health benefits. year. This assistance has a multiplying effect by leading to millions of additional acres of prescribed burning on private Open Biomass Burning12 land annually. Other NRCS forest and range-related practices such as forest stand improvement also can significantly reduce Action to Reduce Wildfire Potential and Severity wildfire potential and severity, thereby greatly reducing A prescribed fire is a fire intentionally ignited in accordance black carbon emissions. In 2011, 51 percent of black carbon with applicable laws, policies, and regulations to meet emissions from open biomass burning were from wildfires, specific objectives. The use of prescribed fire on wildlands 43 percent from prescribed burning, with the remainder can influence the occurrence, severity, behavior, and effects of from agricultural field burning. catastrophic wildfires, and may help mitigate the contribution of wildfires to ambient air pollution levels (particularly ozone Wildfires typically consume greater amounts of fuel with and PM). Prescribed burning is a key management practice little opportunity for smoke management: these pollutants for reducing risk of uncontrolled wildfire, thus helping limit are lofted higher into the atmosphere where longevity and overall fire-related emissions of black carbon. higher wind speeds provide more opportunity for long- range transport than for a prescribed fire. To gain a better The United States Department of Agriculture (USDA) Forest understanding of the Arctic impacts from both prescribed Service’s fuels management program goal is to reduce the fire and catastrophic wildfire in the continental United risks of wildland fire to people, communities, and natural States, the Forest Service conducted an assessment of the resources while restoring forest and rangeland ecosystems to potential for black carbon and other emissions from these closely match their historical structure, function, diversity, sources to be transported into the Arctic based on transport and dynamics. Fuels treatments accomplish these goals by patterns in the atmosphere.13 The analysis concluded that removing or modifying wildland vegetation to reduce the it is possible for black carbon from fires in the contiguous potential for severe wildland fires, lessen the post-fire damage, United States to be transported to the Arctic throughout the and limit the spread or proliferation of invasive species year, but with strong gradients based on initial plume height and diseases. These efforts also reduce emissions and their (i.e. higher lofting provides more opportunity to reach the dispersion high into the atmosphere where lengthy residence Arctic), source region (i.e., lower latitudes and areas west of time and long-range transport, including potentially to the Rocky Mountains show fewer opportunities) and season Arctic regions, is likely. Treatments are accomplished using (i.e., summer transport is limited compared with winter). prescribed fire (intentionally setting fires to destroy excessive There is transport potential during the spring season, when brush, shrubs, and trees under controlled conditions), deposition of black carbon on Arctic snow has the greatest mechanical thinning, herbicides, grazing, or combinations ability to affect the Arctic radiative balance. For any given of these and other methods. Treatments are increasingly location, however, the ability to transport black carbon to the focused on the expanding wildland/urban interface areas. Arctic varies on a daily or weekly basis as large-scale weather Fuels management improves the health and resilience of systems move across country, with particular days showing forests and rangelands, contributes to community adaptation little ability for emissions to reach the Arctic. Similar analysis to fire, and improves the ability to safely and appropriately was also conducted in Europe and Asia. manage wildfire. In 2014, the agency treated more than 2,000,000 acres and has averaged more than 2,400,000 acres The Forest Service has also been involved in research into the annually treated for the previous ten years. smolder potential of critical surface organic layers of certain soils.14 When dry and thus available for consumption in a fire, In 2015, the USDA and Department of Interior finalized these layers can contribute significantly to emissions which the National Cohesive Wildland Fire Management Strategy can cause serious local health effects15 as well as transport which recognizes and responds to the challenge of wildfire in the United States. Three key goals are to support healthier, 13 http://www.firescience.gov/projects/10-S-02-1/project/10-S-02-1_fi- resilient ecosystems that provide many benefits to society, nal_report.pdf including clean water, scenic and recreational values, wood 14 Readon J. and Curcio G. M. 2014. Joint Fire Science Program Final products, and biodiversity; to be committed to safer, more fire- Report: Smoldering Combustion Limits of Organic Soils in the resilient communities; and to respond safely and effectively North Carolina. 15 Rappold A.G., and Others 2011. “Peat Bog Wildfire Smoke Expo- sure in Rural North Carolina is Associated with Cardiopulmonary Emergency Department Visits Assessed through Syndromic Surveil- 12 The National Emissions Inventory includes data for wild- lance.” Environmental Health Perspectives Oct 1, 2011; 119(20): fires, prescribed burning, and agricultural field burning. 1415-1420.

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potential, including to the Arctic. The work has reinforced also benefit from efficiency improvements, which means they the importance of timing prescribed fires in these areas in will use less wood to heat their homes. order to minimize consumption of these layers. Research is continuing, including through use of remote sensing tools to assess the sampled potential of the deep surface fuels found in Oil & Natural Gas some areas of the Southeast, Northeast and upper-Midwest. Coordination on Outer Continental Shelf Oil and Gas Development Residential/Domestic The State of Alaska has regulatory authority (delegated Residential Wood Heaters New Source Performance Standards from the EPA) for permitting certain air emissions from sources located within Alaska including marine areas located In February 2015, the U.S. EPA finalized standards to limit within three miles of the coast. On July 29, 2015, the U.S. the amount of pollution (including PM limits) that wood Bureau of Ocean Energy Management (BOEM) and State heaters manufactured and sold in the future can emit. These of Alaska entered into a Memorandum of Understanding standards reflect the significantly improved technology that on Coordination and Collaboration Regarding Outer is currently available to make a range of models cleaner Continental Shelf Oil and Gas Development and burning and more efficient. The standards ensure that new Environmental Stewardship that among other things contains wood heaters manufactured after the rule took effect will an agreement to set up periodic joint workshops to discuss include only cleaner burning models. The requirements will air quality concerns. be phased in over a five-year period, giving manufacturers time to adapt their product lines to develop the best next- generation models to meet these new standards. Other National Ambient Air Quality Standards PM2.5 emissions from new wood heater models will be reduced by roughly two-thirds, improving air quality and To protect public health and welfare nationwide, the Clean providing between $3.5 and $7.7 billion in public health Air Act requires the U.S. EPA to establish national ambient air benefits (2014 dollars)—a return of between $75 and $168 quality standards (NAAQS) for certain pollutants, including for every dollar invested in pollution reduction. Estimated particulate matter. The Act also requires EPA to review and annual costs of implementing the standard are $46 million. In potentially revise the NAAQS every five years. Meeting the addition, reductions in black carbon from residential sources NAAQS is a partnership between the federal government may have positive climate benefits, particularly in northern and states; states adopt federally enforceable plans to achieve states (including Alaska) where residential sources make up air quality to meet those standards in “non-attainment” areas a greater proportion of black carbon emissions than in the (i.e., locations in which the standards are not met). country as a whole. Consumers purchasing new models will

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Black carbon is a component of PM2.5 and, as such, actions Stationary Diesel Sources taken to reduce PM2.5 may result in reductions in black carbon emissions. In December 2012, the U.S. EPA strengthened The U.S. Department of Agriculture’s Natural Resource Conservation Service (NRCS) leads a voluntary program the annual NAAQS for PM2.5 to 12.0 micrograms per cubic meter (µg/m3) and retained the 24-hour fine particle called the National Air Quality Initiative (NAQI) that is standard of 35 µg/m3. In March 2015, the U.S. EPA proposed part of the Environmental Quality Incentives Program (EQUIP). In many states, especially California, the NAQI is requirements for states to implement the PM2.5 NAAQS in areas that are designated non-attainment for the standard. used to replace older, high-emitting agricultural combustion The requirements would apply to state, local and tribal air equipment with new, low-emitting equipment. Diesel agencies developing plans that outline how non-attainment irrigation pump engines—used on about 10 million irrigated areas will meet and maintain fine particle standards. States acres—are one focus area of the program. Significant emission initially have six years after the effective date of designation reductions are achieved when more efficient and cleaner- as a “Moderate” non-attainment area to meet the revised burning diesel engines are used or when diesel engines are standards. If an area is unable to do so, it will be reclassified replaced by electric motors. In addition to the NRCS’s as a “Serious” non-attainment area and be required to adopt voluntary program, the U.S. EPA has regulations that limit best available control measures in order to attain the standards PM emissions, including black carbon, from new and existing within 10 years of designation. stationary diesel engines.

The U.S. EPA estimates that meeting the annual PM2.5 standard nationwide will provide health benefits worth an METHANE estimated $4 billion to $9.8 billion per year in 2020—a Since the early 1990s, the United States has developed return of $13 to $184 for every dollar invested in pollution numerous voluntary programs and policies to reduce domestic reduction. Estimated annual costs of implementing the methane emissions from large anthropogenic sources. In standard are $57 million to $376 million (2014 dollars). March 2014, the White House released the “Strategy to Reduce Methane Emissions” as part of President Obama’s Proposed Revisions to Regulation of Air Quality on the Outer Climate Action Plan. This Strategy highlights both new Continental Shelf and existing programs aimed at reducing domestic and The U.S. Bureau of Ocean Energy Management (BOEM) international methane emissions through incentive-based regulates emissions of “criteria” air pollutants from energy programs, and research and development efforts to improve and mineral leasing activities on the U.S. Outer Continental methane emissions measurement and to advance methane Shelf (OCS) in in the Central and Western Gulf of Mexico reduction technologies. The strategy focuses on key sectors (West of 87.5 degrees longitude) and the Chukchi Sea and including landfills, coal mines, agriculture, and oil and natural Beaufort Sea adjacent to the northern and northwestern gas and highlights examples of technologies and industry-led coasts (the area offshore the North Slope Borough of the best practices that are helping to cut methane emissions. As State of Alaska). EPA has air pollution control authority for noted below, the White House has also issued a more-detailed other OCS locations and activities.16 strategy on methane emissions from the oil and gas sector. BOEM is currently working on amendments to its existing regulations for criteria pollutants, which are designed to Oil & Natural Gas ensure compliance with NAAQS to the extent that OCS Oil & Gas Methane Strategy activities authorized by BOEM affect the air quality of any Nearly 30 percent of U.S. methane emissions in 2013 came State. PM2.5, including black carbon, is a criteria pollutant. Methane is not a criteria pollutant, but BOEM and the from the production, processing, transmission, storage and Bureau of Safety and Environmental Enforcement (BSEE), distribution of oil and natural gas. Accordingly, a strategy for both bureaus within the Department of the Interior, have cutting methane emissions from the U.S. oil and gas sector is authority to regulate flaring of methane, which generates an important component of efforts to address climate change. PM2.5. BOEM plans to seek comment on black carbon In January 2015, the White House released such a strategy emissions from OCS-related operations and potential and announced a goal to reduce methane emissions from the mitigation measures when it proposes revised air quality oil and natural gas sector by 40–45 percent from 2012 levels regulations. by 2025.17 Achieving this goal would save up to 180 billion cubic feet of natural gas in 2025, enough to heat more than 2 million homes for a year and continue to support businesses 16 The US OCS is comprised of areas lying between the seaward extent that manufacture and sell cost-effective technologies to of the individual States jurisdiction (generally 3 nautical miles identify, quantify, and reduce methane emissions. offshore, 9 for the Texas and Florida Gulf coasts) and the seaward extent of Federal jurisdiction (generally 200 nautical miles offshore). http://www.boem.gov/Outer-Continental-Shelf/ 17 https://www.whitehouse.gov/the-press-office/2015/01/14/fact-sheet- administration-takes-steps-forward-climate-action-plan-anno-1

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The strategy lays out a coordinated cross-agency effort in the agency’s 2012 rules. The U.S. EPA also is proposing to involving the U.S. EPA, the Department of Energy, the require owners/operators to find and repair leaks, which can Department of the Interior and others. It will build upon be a significant source of both methane and VOC pollution. existing research and development, regulatory and voluntary In addition to the requirements for new and modified programs, as well as leadership by states and industry, to emissions sources, draft guidelines for states will reduce achieve significant methane reductions from this sector VOC emissions from existing oil and gas sources in areas with during the next decade. Key components of the strategy smog problems. And two proposals would clarify permitting are outlined below. requirements in states and Indian country and make them more efficient. The U.S. EPA will take comment on the Source Performance Standards proposed rules for 60 days after they are published in the In April 2012, the U.S. EPA issued regulations to reduce Federal Register.18 harmful air pollution from the oil and natural gas industry, including volatile organic compounds (VOCs) and air toxics. Emission reporting The final rules included the first federal air standards for In December 2014, EPA proposed updates to its GHG natural gas wells that are hydraulically fractured, along with reporting requirements that would result in more complete requirements for several other sources of pollution in the oil coverage of methane emissions from the oil and gas industry.19 and gas industry that were not previously regulated at the EPA plans to complete this rulemaking by the end of 2015. In federal level. The rules for fractured gas wells relied on proven, addition, EPA is exploring potential regulatory opportunities cost-effective technologies and practices that industry leaders for applying remote sensing technologies and other were already using at about half of the fractured natural gas innovations in measurement and monitoring technology wells in the United States. to further improve the identification and quantification of The estimated revenues from selling captured gas that would emissions and improve the overall accuracy, transparency, and otherwise have been vented are expected to offset the costs cost-effectiveness of data collection techniques. In addition, of compliance. The U.S. EPA’s analysis of the rules shows a DOE plans to launch a Research and Analysis Program to cost savings of $12 to $21 million (2014 dollars) when the enhance the quantification of emissions from natural gas rules are fully implemented in 2015. The rules are expected infrastructure to include in the national Greenhouse Gas to achieve significant reductions in VOCs and air toxics and Inventory in coordination with the U.S. EPA. Non-federal will improve outdoor air quality, protect against cancer risk efforts to improve data on and estimates of methane emissions from air toxics emissions and reduce health effects associated from the U.S. oil and gas industry are also underway, including with exposure to ground-level ozone. In addition to reducing a multi-study initiative involving more than 100 partners these harmful air pollutants, the rules are expected to yield from industry, research institutions, and civil society.20 significant reductions in methane. The U.S. EPA estimates

methane reductions of 23 to 39 MMT CO2e and estimates Natural Gas STAR Program the value of the climate co-benefits that would result from this The Natural Gas STAR Program is a flexible, voluntary reduction at $480 million annually by 2015. This includes partnership that encourages oil and natural gas companies— the value of climate-related benefits such as avoided health both domestically and abroad—to adopt cost-effective impacts, crop damage and damage to coastal properties. technologies and practices that improve operational efficiency On August 18, 2015, the U.S. EPA proposed a suite of and reduce emissions of methane. These voluntary activities commonsense requirements that together will help combat include nearly 50 technologies and practices and have resulted climate change, reduce air pollution that harms public in domestic methane emissions reductions of 24 MMT

health, and provide greater certainty about Clean Air Act CO2e in 2013. These methane emissions reductions have permitting requirements for the oil and natural gas industry. cross-cutting benefits on domestic energy supply, industrial The proposals are a key component under the President’s efficiency, revenue generation, and greenhouse gas emissions Climate Action Plan described above. These commonsense reductions. The 2013 emission reductions are equivalent standards will reduce emissions from this rapidly growing to the additional revenue of more than $200 million in industry, helping ensure that development of these energy natural gas sales. resources is safe and responsible. These proposals would require methane and VOC reductions from hydraulically fractured oil wells, some of which can contain a large amount of gas along with oil, and would 18 More information about the proposals is available at: http://www. complement the agency’s 2012 standards addressing epa.gov/airquality/oilandgas/actions.html. emissions from this industry. In addition to reducing 19 The proposal would add reporting of GHG emissions from gather- emissions from hydraulically fractured oil wells, the new ing and boosting systems, completions and workovers of oil wells proposals would extend emission reduction requirements using hydraulic fracturing, and blowdowns of natural gas transmis- further “downstream,” covering equipment in the natural gas sion pipelines. The proposal can be found in the Federal Register at transmission segment of the industry that was not regulated 79 FR 73148. 20 https://www.edf.org/sites/default/files/methane_studies_fact_sheet.pdf

12 U.S. NATIONAL BLACK CARBON AND METHANE EMISSIONS A REPORT TO THE ARCTIC COUNCIL

In July 2015, the U.S. EPA released a proposal for a new, $30 million, 3-year program announced22 funding for 11 new expanded voluntary effort, the Natural Gas STAR Methane projects that are each developing low-cost, highly sensitive Challenge, a key component of the Administration’s oil systems that detect and measure methane associated with and gas strategy announced in early 2015. The proposed the production and transportation of oil and natural gas. Methane Challenge program would provide incentives and Additional research efforts supported by DOE include two opportunities for companies to undertake and be recognized projects that were funded to measure and model methane for ambitious voluntary methane emission reductions, emissions from the Marcellus region in Pennsylvania, an principally from existing methane sources. active area for unconventional natural gas development in the United States. Natural Gas Modernization Initiative In April 2015, the Federal Energy Regulatory Commission In 2014, the Secretary of Energy and the White House hosted approved a new policy on Cost Recovery for Natural Gas a series of five methane stakeholder roundtable meetings to Facilities Modernization.23 This policy will allow interstate catalyze greater action and engagement by policymakers at natural gas pipelines to use surcharges to recover costs all levels of government, and encourage industry to invest for capital expenditures to modernize pipeline system in methane abatement actions and participate in voluntary infrastructure, resulting in enhanced system reliability, safety, programs. At the final roundtable, the Department of and methane emissions reductions. Energy (DOE) launched the Natural Gas Modernization 21 In July 2015, DOE joined with the National Association Initiative, which includes a series of efforts designed to of Regulatory Utility Commissioners to launch a Natural help cost-effectively reduce methane emissions from natural Gas Infrastructure Modernization Partnership to provide gas systems. technical assistance to states on model regulatory practices To help reduce the cost of detecting natural gas leaks, to enhance distribution pipeline reliability and cost- DOE hosts the leading U.S. government effort to advance effective methane control technologies to mitigate methane methane-sensing technologies through the Advanced emissions. To further promote awareness and action by Research Projects Agency-Energy (ARPA-E) MONITOR states and industry, the DOE also launched a Natural Gas (Methane Observation Networks with Innovative Technology to Obtain Reductions) program. In December, 2014, this 22 http://arpa-e.energy.gov/?q=news-item/department-energy-announc- es-22-new-projects-enable-emissions-reductions-and-improve-energy 23 http://www.ferc.gov/media/news-releases/2015/2015-2/04-16- 21 http://energy.gov/epsa/natural-gas-infrastructure-modernization 15-G-1.asp#.Vbk63PlViko

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Modernization Clearinghouse,24 which provides information from coal mining activities by promoting the profitable about the benefits of taking action and offers strategies and recovery and utilization of coal mine methane. Since 1994, technologies that increase public safety, improve efficiency CMOP has worked cooperatively with the coal mining and environmental performance, and enhance natural gas industry to promote coal mine methane projects, which deliverability. improve worker safety, lower methane emissions, provide In addition to these activities, DOE plans to develop a additional revenue for the mines, and utilize a clean energy midstream natural gas infrastructure program to focus on resource. As of 2012, there were 26 operating coal mine reducing methane leaks and enhancing operational efficiencies methane projects in the United States. The program has of pipelines, storage facilities, and compressor stations, as helped to reduce coal mine methane emissions by more than 8 MMT CO e in 2013, and has achieved cumulative well as on communicating results to stakeholders to mitigate 2 reductions of more than 160 MMT CO e since the program methane emissions. 2 began in 1994. Reduced Methane Emissions from Pipelines The DOT’s Pipeline and Hazardous Materials Safety Administration is developing a suite of new regulations to require pipeline operators to extend their programs to detect and repair pipeline defects, and to increase use of automatic shut-off valves for retail customers primarily to ensure public safety. These regulations, when promulgated, will also reduce leakage from pipelines and also reduce the frequency and severity of methane loss and uncontrolled combustion from accidents.

Proposed Regulations to Reduce Venting and Flaring from Public Lands The Department of Interior’s Bureau of Land Management (BLM) will update decades-old standards to reduce wasteful venting, flaring, and leaks of natural gas, which is primarily methane, from oil and gas wells. These standards, to be proposed this fall, will address both new and existing oil and gas wells on public lands. This action will enhance Agriculture U.S. natural gas supplies and assure appropriate payment Agricultural emissions of methane result from several sources. of royalties from development of public resources, as well Chief among these is enteric fermentation, a process through as reduce methane emissions. The BLM is working closely which microbes present in the digestive tract of livestock with the EPA to ensure an integrated approach. (primarily ruminants, such as cattle, sheep, and goats) break down ingested feed, emitting methane as a byproduct. Animal type, quantity and quality of the feed source, additives, and other factors influence methane emissions from enteric fermentation. Although methane emissions from enteric fermentation exceed those from manure management, the opportunities for reducing emissions from enteric fermentation are not well understood. For that reason, mitigation options for this sector focus primarily on those applicable to manure management through the use of anaerobic digestion techniques. 25 These technologies capture biogas that is created when animal waste (manure) decomposes under low-oxygen conditions.

AgSTAR AgSTAR was launched as a voluntary effort by the U.S. EPA Coal Mining with collaboration from USDA in 1993 to encourage the use of methane recovery technologies at confined animal feeding Coalbed Methane Outreach Program operations that manage manure as liquids or slurries. AgSTAR also works to identify and address barriers to installation of The U.S. EPA’s voluntary Coalbed Methane Outreach biogas recovery projects, as well as to provide information Program (CMOP) has the goal of reducing methane emissions and training to state and local government agencies.

24 http://energy.gov/epsa/natural-gas-modernization-clearinghouse 25 http://www2.epa.gov/agstar

14 U.S. NATIONAL BLACK CARBON AND METHANE EMISSIONS A REPORT TO THE ARCTIC COUNCIL

As of March 2015, there were 247 operating AgSTAR projects The proposals would strengthen a July 2014 proposal to in the United States. Estimated benefits of these projects in update the agency’s 1996 New Source Performance Standards

2014 include 3.0 MMT CO2e emissions avoided. for new and modified landfills and would update the agency’s 1996 emission guidelines for existing landfills. The proposals Biogas Opportunities Roadmap are based on additional data and analysis, and public comments received on a proposal and Advance Notice of In August of 2014, in partnership with the dairy and biogas Proposed Rulemaking EPA issued in 2014.27 U.S. EPA will industries, the USDA, U.S. EPA and the DOE jointly released take comment on the proposed rules for 60 days after they a “Biogas Opportunities Roadmap” outlining voluntary are published in the Federal Register. strategies to accelerate adoption of methane digesters and other cost-effective technologies.26 The Roadmap, which supports the U.S. dairy sector’s voluntary goal established in 2008 to reduce its greenhouse gas emissions by 25 percent by 2020, found that with the proper support, more than 11,000 additional biogas systems could be deployed in the United States. If fully realized, these biogas systems could reduce methane emissions equivalent to 4 to 54 million metric tons of greenhouse gas emissions in 2030. TheBiogas Opportunities Roadmap builds on progress made to date to identify voluntary actions that can be taken by government agencies to reduce methane emissions through the use of biogas systems and outlines strategies to overcome barriers limiting further expansion and development of a robust biogas industry in the United States. These steps include the use of existing programs (such as AgSTAR) by USDA, DOE, and EPA to enhance the utilization of biogas systems in the United States. In addition, USDA and DOE will review applicable loan and grant programs to enhance the financing options available for biogas systems. The three Landfill Methane Outreach Program agencies will continue to provide technical information to The U.S. EPA’s Landfill Methane Outreach Program (LMOP) overcome barriers, including the integration of biogas into reduces methane emissions at MSW landfills by supporting electricity and renewable natural gas markets. Finally, the the voluntary recovery and use of landfill gas for energy. agencies will increase stakeholder engagement activities to LMOP focuses its efforts on smaller landfills that are not widely disseminate information about these opportunities required to collect their landfill gas, as well as larger landfills and technical resources. that collect their gas but flare it rather than use it as an energy source. Landfills As of 2013, there were 634 operational landfill gas to energy projects in the U.S., of which LMOP assisted more Performance Standards and Emission Guidelines than 600. In 2013, the program’s efforts reduced methane On August 14, 2015, as part of the Strategy to Reduce emissions from landfills and avoided CO2 emissions totaling Methane Emissions described above, EPA issued two proposals approximately 40 MMT CO2e. Over 600 LMOP-assisted to further reduce emissions of methane-rich landfill gas from projects landfill gas energy projects have collectively reduced new and existing municipal solid waste (MSW) landfills. Both and avoided over 306 MMT CO2e since the program began rules would require landfills to begin collecting and controlling in 1994. landfill gas emissions at lower thresholds (34 metric tons) than currently required. Combined, the proposed rules are expected to reduce methane emissions by an estimated 487,000 tons a year beginning in 2025—equivalent to reducing 12.2 million metric tons of carbon dioxide.

27 More information about the proposals is available at: 26 http://www.epa.gov/climatechange/Downloads/Biogas-Roadmap.pdf http://www.epa.gov/ttnatw01/landfill/landflpg.html.

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HIGHLIGHTS OF BEST PRACTICES AND LESSONS LEARNED FOR KEY SECTORS

(See pages 6-15 for additional details on the programs described as passenger cars and light-duty trucks being replaced more below.) frequently than some other types of mobile sources, such as nonroad equipment. Efforts to address older vehicles and engines through voluntary programs and grants or loans to TRANSPORT/MOBILE operators to upgrade diesel engines and controls can have significant positive impacts on overall diesel and related Considerations Impacting Effectiveness of Regulations black carbon emissions. Ultra-low sulfur diesel fuel In issuing diesel PM regulations for onroad heavy-duty OPEN BIOMASS BURNING (INCLUDING vehicles, nonroad diesels, and commercial marine (categories 1 WILDFIRES) and 2) engines and/or locomotives, the U.S. EPA determined that the required emission standards could only be met in Timing of Prescribed Burns combination with ultra-low sulfur diesel (ULSD) fuel. ULSD fuel is an important prerequisite for the application of DPFs The climate impact of wildlands fires in the continental in order to preserve catalytic activity of the emission control U.S.—both wildfires and prescribed burns—can vary substantially depending on timing and location. The ability system, which is poisoned by sulfur. of black carbon from fires from the continental US to be “Legacy” fleets transported to the Arctic exists throughout the year, but with strong gradients by region (i.e., much lower west of In addition, the transportation-related emission reductions the Rocky Mountains) and season (i.e., more than twice as realized as a result of a regulation depend on the rate of fleet high in winter versus summer).28 While there is potential for turnover—i.e. the rate at which older vehicles and engines transport between the continental U.S. and the Arctic during are replaced with new vehicles that comply with the latest emissions standards. The rate of fleet turnover depends heavily 28 http://www.firescience.gov/projects/10-S-02-1/project/10-S-02-1_fi- on the type of vehicle or engine, with onroad engines such nal_report.pdf.

16 U.S. NATIONAL BLACK CARBON AND METHANE EMISSIONS A REPORT TO THE ARCTIC COUNCIL

the spring season, when deposition of black carbon on Arctic snow has the greatest ability to affect the Arctic radiative OIL & NATURAL GAS balance, the potential for transport changes throughout the season as different weather patterns move across the country. Natural Gas STAR Timing prescribed burns based on this information can help Working with industry partners, the voluntary Natural Gas lower the climate impact to the Arctic. STAR program has developed numerous Lessons Learned Studies32 for recommended technologies and practices within Both USDA Forest Service and USDA Natural Resources the oil and gas sectors that provide technical guidance and Conservation Service published the Basic Smoke outline the economic and environmental benefits of adoption. Management Practices Tech Note, October 2011, which describes approaches to minimizing emissions and impacts of prescribed burning in the United States.29 These practices OTHER have utility for open burning of natural ecosystems as well as many agricultural systems where fire is needed and used. Both agencies have adopted the practices in policy to help mitigate Arctic Black Carbon Case Studies Platform the air quality effects of needed prescribed fire operations. In October 2013, Senior Arctic Officials—individuals appointed by the eight Arctic States to represent their countries at the Arctic Council—approved a case studies RESIDENTIAL/DOMESTIC project to catalogue black carbon mitigation efforts and best practices. The first phase of the project included an initial set of six case studies, which has been completed and posted on U.S. EPA Burn Wise Program the Arctic Contaminants Action Program website.33 Project In addition to its regulatory program, the U.S. EPA has leads, including the U.S. EPA, are currently compiling conducted extensive education and outreach related to 30 additional case studies and a searchable platform that can residential biomass burning. EPA’s Burn Wise website be easily maintained by the Arctic Council Secretariat is includes information that emphasizes the importance of under development. burning the right wood, the right way, in the right wood- burning appliance to achieve health, safety and air quality goals. One of the biggest opportunities to reduce wood smoke Global Methane Initiative emissions, including black carbon, lies in the hands of those The United States chairs the Global Methane Initiative who burn wood, regardless of the type of appliance they (GMI), a public-private partnership with 43 partner own. The way wood stoves are operated and what is burned countries,34 which targets methane abatement, recovery, are as important as the type of stove used. State, local, and and use by focusing on the five main methane emission tribal governments, and the public have reported to EPA sources: agriculture (manure management), coal mines, that even people who own an EPA-certified wood stove are municipal solid waste landfills, oil and gas systems, and often times burning “green” unseasoned wood, trash, and/ wastewater. GMI identifies mitigation opportunities and or improperly operating their appliance, resulting in high disseminates information about best practices for each sector, wood smoke emissions. The information available on the focusing on currently available technologies and relevant Burn Wise website can help stove users better understand policy measures. GMI is a forum in which Arctic countries actions they can take to reduce emissions.31 can actively engage and play a leadership role with respect to methane mitigation practices, as technologies and practices that have been identified for Arctic nations can be relevant for other countries and world regions.

29 http://www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/stel- prdb1046311.pdf 32 http://www.epa.gov/gasstar/tools/recommended.html 30 http://www.epa.gov/burnwise/ 33 http://www.arctic-council.org/index.php/en/black-carbon-case-stud- 31 Additional strategies for reducing wood smoke see can be found at ies (ACAP login required for access.) www.epa.gov/burnwise/strategies.html. 34 https://www.globalmethane.org/

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PROJECTS RELEVANT FOR THE ARCTIC

Through its long-standing cooperative relationship with the ARCTIC AIR QUALITY IMPACT ASSESSMENT Russian Federal Forestry Agency’s Aerial Forest Fire Center, MODELING the Forest Service has undertaken joint trainings on fire The Bureau of Ocean Energy Management is currently suppression techniques and improving efforts to protect conducting the “Arctic Air Quality Impact Assessment communities and property from wildfire. Modeling” study,35 which is designed to account for all reasonably foreseeable emissions that would occur from oil and gas activities on the Chukchi and the Beaufort Seas, MEASUREMENT OF BLACK CARBON AND including an investigation of both directly-emitted and METHANE IN THE ARCTIC photochemically-formed PM2.5 emissions. The study will also account for methane emissions originating from operational The National Oceanographic and Atmospheric flaring, venting, and fugitive emissions. Administration’s Global Monitoring Division (NOAA GMD) has conducted long-term, continuous equivalent black carbon measurements at three Arctic Monitoring BLACK CARBON DEPOSITION ON U.S. Stations: Barrow, Alaska (1988–2015); Summit, Greenland (2003–2015); Tiksi, Russia (2009–2015), and in cooperation SNOW PACK with Environment Canada at Alert, Canada (1989–2015). The U.S. Forest Service is participating in a Washington During the past decades there has been an approximately State University project, which will be completed this year, 50% decrease in aerosol and black carbon concentrations on domestic black carbon deposition on U.S. snowpack observed at the two stations with the longest records, Barrow including the Alaskan Arctic. and Alert.

An overview report on the state of the science of black carbon NOAA GMD has been monitoring methane in the Arctic emissions from wildfires was developed by Forest Service’s since 1983 from 11 sites ringing the Arctic Ocean including Research and Development Program, and was published as two in Russia. Total methane emissions in the Arctic are a special issue of Forest Ecology and Management.36 roughly half from natural and half from anthropogenic sources, with available data indicating that there is no evidence yet that methane emissions from melting permafrost EMISSIONS AND TRANSPORT FROM have responded to increasing Arctic temperatures. The largest observed change, a decrease in methane emissions, occurred AGRICULTURAL BURNING AND FOREST FIRES immediately after economic restructuring in the former The U.S. Forest Service’s Rocky Mountain Research Station Soviet Union in 1991. The isotopic composition of methane prepared improved emissions inventories from wildland fire is like a fingerprint that can be used to determine if Arctic and conducted full photochemical modeling in conjunction methane is from fossil sources or of recent biological origin with University of California Los Angeles.37,38 released from the melting of permafrost.

The U.S. Forest Service’s Pacific Northwest Research Station examined the capability of prevailing atmospheric patterns MEASUREMENT OF MARITIME BLACK to transport black carbon to the Arctic from Eurasia, and CARBON EMISSIONS AND DIESEL FUEL created an almanac and forecast product to indicate good times to burn to mitigate Arctic impacts from black carbon. ALTERNATIVES In 2015, the U.S. Maritime Administration (MARAD) joined with the International Council on Clean Air to conduct further research on black carbon emissions from marine 35 http://www.boem.gov/AK-13-01/ engines and mitigation methods to reduce those emissions. 36 (vol. 317, 2014). The project includes bench and in-situ emissions testing of 37 Hao, W.M., A. Petkov, B.L. Nordgren, R.P. Silverstein, R. Corley, control technologies for black carbon emissions. MARAD S.P. Urbanski, N. Evangeliou, Y. Blakanski, and B. Kinder. “Daily is also actively evaluating the potential of alternative fuels black carbon emissions from fires in Northern Eurasia”, Atmos. 39 Chem. Phys., in preparation and technologies for marine propulsion. Among that work 38 Evangeliou, N., Y. Blakanski, W.M. Hao, A. Petkov, B.L. Nordgren, has been a study of the total fuel cycle for liquified natural R.P. Silverstein, S. Eckhardt, A. Stohl, and S.P. Urbanski. “Wildfires in Eurasia affect the budget of black carbon in the Arctic. A 12-year retrospective synopsis (2002-2013)”, Atmos. Chem. Phys., in 39 http://www.marad.dot.gov/wp-content/uploads/pdf/DNVLNG- preparation. BunkeringStudy3Sep14.pdf

18 U.S. NATIONAL BLACK CARBON AND METHANE EMISSIONS A REPORT TO THE ARCTIC COUNCIL

gas compared to conventional fuels and a study of methane Additionally, the U.S. EPA projects resulted in guidelines for release from bunkering activities and during ship operations.40 mines purchasing offroad vehicles in a report, “Evaluation of In addition, MARAD continues to work with the maritime Black Carbon Emission Reductions from Mining Trucks in industry and with other Federal agencies to assess various Russia: The Case of the Murmansk Region,” and published emissions control technologies for ships and alternative in the Russian journal Mining Industry in August 2015. A fuels and technologies such a bio-diesel and fuel cells.41,42,43 circumpolar policy and financing recommendations report, “Circumpolar Best Practices: Policy and Financing Options for Black Carbon Emission Reductions from Diesel Sources,” REDUCTION OF BLACK CARBON IN THE is under review and expected in late 2015 as an Arctic RUSSIAN ARCTIC Council publication. Under the U.S. Department of State’s Arctic Black Carbon The U.S. DOE project, which is wrapping up in 2015, focused Initiative (ABCI), the U.S. EPA, U.S. DOE, U.S. Forest on reducing black carbon emissions from heating, power Service, and partners have undertaken several projects in generation, and industrial applications. As part of the DOE 46,47 Russia to leverage resources and best practices across the Arctic project, two peer-reviewed articles have been published in order to understand and mitigate black carbon emissions. (Cheng, 2014; Huang et al., 2014) and one is expected to be published in 2015. A new inventory for all black carbon The U.S. EPA projects focus on reducing black carbon sources was developed for Russia and was finalized in 2014. emissions from diesel sources. As part of one EPA project, an Significant progress has been made through this project in emissions inventory for diesel sources from the Murmansk understanding Russian regional sources, transport, and fate area in Russia finalized in October 2014 found that off-road of black carbon emissions, Russian regional energy usage, and vehicles at mines and on-road vehicles were top sources. A 44 the potential for reducing black carbon emissions through peer-reviewed article has been published in July 2015 and energy efficiency measures and fuel switching. Oak Ridge another will be published later in 2015. In addition to the National Laboratory is currently drafting a technical report to emission inventory, work in Murmansk included a pilot summarize the range of activities, findings, and engagement mitigation project to upgrade part of the bus fleet at a local achieved during the project, and to provide recommendations bus company. This resulted in a 90 percent decrease in black for follow-on work that can extend the impact of the project. carbon emissions for these upgraded buses compared to the buses that were replaced as well as significant reductions in The U.S. Forest Service project focused on reducing black other pollutants, reduced fuel, operating and maintenance carbon emissions from biomass combustion. The U.S. Forest costs and improved service. An Arctic Council publication Service and USDA’s Agricultural Research Service and Foreign brochure describing the results of this project is available in Agriculture Service worked with Russian partners to quantify 45 both Russian and English. black carbon emissions from agricultural burning and forest The U.S. EPA also partnered with the Nordic Environmental fires in Russia, to model transport of black carbon from Finance Corporation on a pilot project developing wind- these sources to the arctic, and to develop tools and identify diesel alternatives to traditional diesel-powered generators feasible mitigation options to reduce black carbon emissions at remote Tundra Collective reindeer farm in the Murmansk from these sources. region. The wind turbine and new diesel generator were installed in Spring 2015. Once operational, it is estimated that the consumption of diesel at the farm will be reduced VALDAY CLUSTER UPGRADE FOR BLACK by as much as 90% and, as a result, diesel black carbon emissions from the cooperative will also be reduced by as CARBON REDUCTION IN THE REPUBLIC OF much as 90%. The efficiency of the new system will also allow inhabitants at the farm to convert to electric heating KARELIA, RUSSIAN FEDERATION units instead of using wood stoves, dramatically improving The U.S. EPA has partnered with the Nordic Environmental indoor air quality for Tundra inhabitants. Finance Corporation on the Valday Cluster upgrade project, which aims to implement a range of alternatives for providing energy to off-grid settlements in the Republic of Karelia 40 http://www.marad.dot.gov/wp-content/uploads/pdf/Total_Fuel_Cy- in Russia. Currently, these settlements largely use diesel cle_Analysis_for_LNG.pdf generators for power. Benefits include potential improvements 41 http://www.marad.dot.gov/wp-content/uploads/pdf/The_Use_of_ in services, emission reductions, energy savings, and lessons Biodiesel_Fuels_in_the_US_Marine_Industry.pdf learned that will contribute to an improved energy system 42 http://www.marad.dot.gov/wp-content/uploads/pdf/Sugar-Based_ across this Cluster. Project implementation is expected to Renewable_Diesel_Testing_Final_Report_August_30_2013.pdf begin soon. 43 http://www.marad.dot.gov/newsroom/news_release/2015/ maritime-administration-provides-500000-to-study-hydro- gen-fuel-cell-technology-for-maritime-applications/ 46 Huang et al. “Identification of Missing Anthropogenic Emission 44 http://www.atmos-chem-phys.net/15/8349/2015/acp-15-8349-2015 Sources in Russia: Implication for Modeling Arctic Haze.” Aerosol 45 https://oaarchive.arctic-council.org/bitstream/handle/11374/389/ and Air Quality Research, 14: 1799–1811, 2014. ACMMCA09_Iqaluit_2015_ACAP_Murmansk_bus_fleet_up- 47 Cheng. “Geolocating Russian sources for Arctic black carbon.” grade.pdf?sequence=1 Atmospheric Environment, 92, 398-410, 2014.

19 U.S. NATIONAL BLACK CARBON AND METHANE EMISSIONS

relationship to sources that help explain seasonal variations AVIATION CLIMATE CHANGE RESEARCH in soot deposition in the Arctic. This finding will contribute INITIATIVE to insights on the impact of darkened snow and ice on the In the past five years the Federal Aviation Administration ability of the Arctic surface to reflect light and heat back into (FAA) funded several activities under its Aviation Climate the atmosphere. The new technique enables quantification Change Research Initiative48 as part of its Climate Change of the global impact of black carbon originating from many Research program to study the aviation effects on global different regions and source types. climate in general and regional climate in particular The PNNL research team implemented, for the first time, (including the arctic region). As part of this effort ten a technique to quantify and track black carbon emissions teams from universities, national laboratories and industry, from their source to their destination (known as receptor investigated using global climate models, satellite observations regions), especially the Arctic. The researchers used a global and laboratory measurements, the effect of aviation emissions aerosol-climate model called the Community Atmosphere including emissions of methane and black carbon, currently Model version 5 (CAM5) and constrained the simulations to and into the future when the aviation activity is expected to align with observed meteorology for the 1995–2005 period. increase substantially. The merits of rerouting of cross-polar The team was able to take advantage of another recent PNNL 49 flights around the Arctic Circle were also investigated. study that modified CAM5 aerosol-cloud representations to improve the reliability of aerosol simulations for the Arctic. The black carbon source tagging technique they developed TRACKING SOURCES OF BLACK CARBON IN allowed relationships between black carbon sources and black THE ARCTIC carbon reaching the Arctic to be derived without actually To better understand how the Arctic climate responds to perturbing emissions, as is often done in similar studies. changing levels of black carbon and the effectiveness of Previous emissions tagging studies reduced the emissions possible mitigation efforts to reduce warming, it is necessary and performed multiple simulations, which would introduce to accurately identify the sources and quantities of black errors due to non-linearities in the aerosol processes; the carbon from each world region. Researchers at Pacific current method treats each emission region as a distinct Northwest National Laboratory (PNNL) designed a new tracer, providing a more accurate result. way to identify and track the sources of black carbon and The tagging technique allowed identification of the amount how they are transported to the Arctic using an atmospheric of black carbon in the air and the amount deposited to computer model and a new technique for tagging black the snow and ice surface that originates in different source carbon emissions.50 The simulation shows the pathways and regions. The modelling studies found that Arctic black carbon concentrations, deposition, and source contributions all have 48 http://www.faa.gov/about/office_org/headquarters_offices/apl/re- strong seasonal variations. Eastern Asia contributes the most search/science_integrated_modeling/accri/ to the wintertime Arctic black carbon burden, but has much 49 “The effects of rerouting aircraft around the arctic circle on arctic less impact on lower-level concentrations and deposition. and global climate” by M. Z. Jacobson, J. T. Wilkerson, S. Balasu- Northern Europe emissions are more important to both bramanian, W. W. Cooper Jr., and N. Mohleji. Climatic Change surface concentration and deposition in winter than in (2012) 115:709 – 724, DOI 10.1007/s10584-012-0462-0 summer. The largest contribution to Arctic black carbon in 50 Wang H, Rasch PJ, Easter RC, et al. “Using an Explicit Emission Tagging Method in Global Modeling of Source-receptor Rela- the summer is from Northern Asia. Although local emissions tionships for Black Carbon in the Arctic: Variations, Sources, and contribute less than 10% to the annual mean black carbon Transport Ways.” Journal of Geophysical Research Atmospheres. burden and deposition within the Arctic, the per-emission 2014;119:12,888-12,909. efficiency is much higher than for non-Arctic sources.

OTHER INFORMATION

Item 6 in the Framework’s Guidance for National Submissions and mitigation).” For continuity, such information has been suggests including “other information if available (e.g., integrated into the preceding sections of this report. climate, health, environmental, economic effects of emissions

20 U.S. NATIONAL BLACK CARBON AND METHANE EMISSIONS A REPORT TO THE ARCTIC COUNCIL

Appendix—Detailed Emissions Data

21 U.S. NATIONAL BLACK CARBON AND METHANE EMISSIONS

APPENDIX 1: U.S. BLACK CARBON EMISSIONS

2011 Black Carbon Emissions Black Carbon Emissions 2011 Sector SubSector Emission_Ton Emission_Mg Fires 235,479 213,626 Source: U.S. EPA 2011 NEI v1; 2011 v6 Wildfires 119,043 107,995 Emissions Modeling Platform Prescribed Fires 101,047 91,670 These data are the same as previously Agricultural Field Burning 15,389 13,961 submitted - for RY2014, See Notes_ BlackCarbon. Mobile Nonroad * 125,699 114,034 For sum totals, additional unit of measure is DieselEquipment 78,016 70,776 given in kilotonne, kt Railroad 19,920 18,071 CMV 15,113 13,711 Emissions in Tons and Mg Gas 6,590 5,979 1 short ton = .9072 tonne 1 tonne = 106g or Mg; Aircraft 5,657 5,132 short ton x .9027 = Mg Other 403 365 1000 Mg = 1 kilotonne 1 Mg = .001 kt Mobile Onroad * 107,358 97,395 DieselHeavyDuty 93,749 85,049 GasLightDuty 10,526 9,550 DieselLightDuty 2,688 2,438 GasHeavyDuty 394 358

Fuel Combustion 64,423 58,445 Fuel Combustion Tons Biomass 26,124 23,700 Residential IndusBoilers Comm/Instit ElecGeneration TOTAL NaturalGas 21,898 19,866 Biomass 21,743 3,894 417 70 26,124 Coal 7,821 7,095 NaturalGas 284 9,803 2,281 9,531 21,898 Oil 4,442 4,030 Coal 886 60 6,875 7,821 Other 4,139 3,755 Oil 613 1,453 922 1,454 4,442 Other 204 3,045 228 662 4,139 Misc Other 22,998 20,864 MiscWasteDisposal 18,725 16,987 Fuel Combustion Mg MiscCommCook 2,844 2,580 Residential IndusBoilers Comm/Instit ElecGeneration TOTAL DustPavedUnPavedRoads 1,267 1,150 Biomass 19,725 3,533 379 63 23,700 Agriculture 101 92 NaturalGas 257 8,893 2,069 8,647 19,866 MiscNon-IndustrialNEC 60 55 Coal 804 54 6,237 7,095 Oil 556 1,318 837 1,319 4,030 Industrial Processes 9,539 8,654 Other 185 2,762 207 601 3,755 Industrial Processes 9,420 8,546 SolvCommercialIndustrial 118 107 SolvConsumerCommercial 1 1 0 Total 565,495 513,017 Total without Wildfire 446,452 405,022

Source: U.S. EPA 2011 NEI V1; 2011v6 Emissions Modeling Platform * In future versions of the 2011 NEI, the relative contribution of black carbon emissions for mobile sources may change as speciation factors are updated for individual mobile sources such as nonroad gasoline, aircraft and large commercial marine vessels, though the difference in the total contribution from mobile sources is not expected to be significant. (kt) Total 513 (kt) Total w/o 405 Wildfire

22 U.S. NATIONAL BLACK CARBON AND METHANE EMISSIONS A REPORT TO THE ARCTIC COUNCIL

The black carbon (BC) emissions included in this report are the same as previously provided - RY2014. The last report of BC emissions was based on the 2011 v1 and since that time, 2011 v2 has been completed. Based on the 2011 v2, there is an overall small decrease (approximately 7% decrease) in national BC emissions which results from the emission sectors

where PM2.5 decreases the most in the 2011 v2 from the 2011 v1. The largest PM2.5 decreases (in tons) are for the sectors: mobile on-road diesel heavy duty vehicles (-9,399); prescribed burning (-18,369); agricultural field burning (-45,455); and wildfires (-141,626) though this sector is excluded for LRTAP report purposes. The Notes section for Main Pollutants discusses the basis for the larger changes in v2 from v1. Because the change in overall BC emissions are small compared to that last reported, the routine

of processing the BC data from the PM2.5 emissions was not repeated for the updating done here. The next complete national inventory (NEI) for 2014 version is expected to be available in July 2016. The availability of the 2014 NEI may provide the next

opportunity to develop updated BC emissions from the PM2.5 data.

The notes below appeared with the RY2014 IIR.

Black Carbon (Notes RY2014) Included here for RY 2014, and for the first time on a voluntary basis, are black carbon (BC) emission estimates for the year 2011. Currently, the U.S. EPA does not require the states to report emissions of black carbon and other PM constituents (organic carbon - OC, nitrates, sulfates, and crustal material) as part of the National Emissions Inventory (NEI). Rather,

the U.S. emissions inventory uses total PM2.5 emissions to derive estimates for direct emissions of carbonaceous particles, including BC and OC. The Annex IV Table 1 does not presently include a place to report black carbon emissions. Therefore the national pollutant totals for 2011 are presented in this Inventory Informative Report (.xls) and summarized by categories other than NFR, that are specific to the U.S. NEI emission categories, i.e., EIS sectors (60). The emissions estimates represent all of the U.S. and associated territories including Puerto Rico (PR) and Virgin Islands (VI), as well as Tribal lands, and federal waters (offshore). The significant contribution of black carbon is from: mobile source diesel equipment and engines; biomass burning from wild and prescribed fires; and fuel combustion - residential wood and EGUs (electric utility generation). In future versions of the 2011 NEI, the relative contribution of black carbon emissions for mobile sources may change as speciation factors are updated for individual mobile sources such as nonroad gasoline, aircraft and large commercial marine vessels, though the difference in the total contribution from mobile sources is not expected to be significant.

Methods The 2011 PM2.5 emission data in the EPA 2011 NEI v1 is the basis for the 2011 black carbon emission included in this report. The PM2.5 emissions were speciated for the PM species including black carbon, via processing routine associated with the EPA 2011 emissions modeling platform, See http://www.epa.gov/ttn/chief/emch/index.html, 2011v6 Platform. The 2011 platform Technical Support Document (TSD) describes the methodology used to estimate the PM species. The document title is Preparation of Emissions Inventories for the Version 6.0, 2011 Emissions Modeling Platform and is located on the EPA Emissions Modeling Clearinghouse: http://www.epa.gov/ttn/chief/emch/index.html. The TSD includes a description and reference for the black carbon speciation factors from SPECIATE for important BC categories (residential wood combustion, burning, diesels, etc.)

The PM2.5 values for the dust sectors were modified with meteorological - and land-use- based adjustments as part of the emissions modeling process. Dust sources include paved and unpaved roads, agriculture activities with crops and livestock,

and mining activities. The meteorological and land-use adjustments to the dust PM2.5 results in a more appropriate mix of species (in the atmosphere) for input into the air quality modeling chemistry. The partitioning of PM2.5 species for dust is our best emission estimate of the PM species from processes that produce dust. Only the PM values for dust were adjusted prior to further speciation. The dust adjusted results for the PM species are included for these national sector summaries of black carbon. The amount of black carbon from dust is insignificant compared to all sectors. For onroad mobile, the EPA model MOVES is used to estimate emissions. MOVES activity data and inputs were obtained

directly from states. For California and Texas, they submitted PM2.5 emissions directly to the NEI which were utilized to estimate the black carbon emission species.

23 U.S. NATIONAL BLACK CARBON AND METHANE EMISSIONS

APPENDIX 2: U.S. METHANE EMISSIONS (MMT CO2E), 1990–2013

Methane source sector 1990 2005 2009 2010 2011 2012 2013 Enteric Fermentation 164.2 168.9 172.7 171.1 168.7 166.3 164.5 Natural Gas Systems 179.1 176.3 168.0 159.6 159.3 154.4 157.4 Landfills 186.2 165.5 158.1 121.8 121.3 115.3 114.6 Coal Mining 96.5 64.1 79.9 82.3 71.2 66.5 64.6 Manure Management 37.2 56.3 59.7 60.9 61.4 63.7 61.4 Petroleum Systems 31.5 23.5 21.5 21.3 22.0 23.3 25.2 Wastewater Treatment 15.7 15.9 15.6 15.5 15.3 15.2 15.0 Rice Cultivation 9.2 8.9 9.4 11.1 8.5 9.3 8.3 Stationary Combustion 8.5 7.4 7.4 7.1 7.1 6.6 8.0 Abandoned Underground Coal Mines 7.2 6.6 6.4 6.6 6.4 6.2 6.2 Forest Fires 2.5 8.3 5.8 4.7 14.6 15.7 5.8 Mobile Combustion 5.6 3.0 2.3 2.3 2.3 2.2 2.1 Composting 0.4 1.9 1.9 1.8 1.9 1.9 2.0 Iron and Steel Production & Metallurgical 1.1 0.9 0.4 0.6 0.7 0.7 0.7 Coke Production Field Burning of Agricultural Residues 0.3 0.2 0.3 0.3 0.3 0.3 0.3 Petrochemical Production 0.2 0.1 + 0.1 + 0.1 0.1 Total 745.5 707.8 709.5 667.2 660.9 647.6 636.3

Source: Table ES-2 of EPA’s Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990–2013 Report. Annual data from all years spanning the 1990–2013 time period are available in the Main Report Tables files available online at: http://www.epa.gov/climatechange/ghgemissions/usinventoryreport.html

+ indicates sources with annual methane emissions not exceeding 0.05 MMT CO2e. Additional sectors that do not exceed this value for any measured year include: Ferroalloy Production, Silicon Carbide Production and Consumption, Peatlands Remaining Peatlands, and Incineration of Waste.

CO2e values reflect the IPCC AR4 100-year time horizon GWP of 25.

24 U.S. NATIONAL BLACK CARBON AND METHANE EMISSIONS COVER PHOTO: BUREAU OF LAND MANAGEMENT, BOB WICK; ALL OTHER PHOTOS: ISTOCK.COM DESIGNED AND PRINTED BY A/GIS/GPS, AUGUST 2015