Sources of Black Carbon
Black carbon is released into the atmosphere from the incomplete combustion of fossil fuels, biofuels and biomass. Black carbon emissions result mainly from four source categories: (1) diesel engines for transportation and industrial use; (2) residential solid fuels such as wood and coal; (3) open forest and savanna burning, both natural and initiated by humans for land clearing; and (4) industrial processes, usually from small boilers.35
The relative contribution of black carbon from combustion sources varies considerably with source type. Since black carbon is emitted with other particulates, including some that are light-reflecting and therefore have a cooling effect, fuel source and burning process will determine the net warming effect of combustion. When fossil fuels, such as oil and coal, are incompletely combusted (i.e., not completely oxidized to carbon dioxide), black carbon tends to be formed in much larger amounts than organic carbon.36 For this reason, soot from diesel combustion usually appears black because it contains a high fraction of black carbon, which absorbs all colors of visible light. Soot from biofuel is brownish because it contains a higher ratio of organic carbon to black carbon than diesel soot.37 When biomass fuels, such as wood, are incompletely combusted, organic carbon is formed in greater amounts than black carbon.38 Organic carbon is generally thought to have a direct cooling effect because it reflects incoming sunlight. Thus, black carbon mitigation should take into account the co-effects of associated organic carbon reductions.39 An optimal decrease in the warming effects of aerosols can be achieved by targeting subsectors, such as diesel combustion, which emit a relatively large percentage of black carbon.40
Because of its low contrast with the snow and ice-covered surfaces, the general cooling effect of bright aerosols such as sulfates and organic matter that are emitted along with black carbon have relatively little, if any, cooling effect on snow and ice-covered6
41 Hearing, supra note 15, at 72 (statement of Charles Zender, Associate Professor, University of California at Irvine).
42 V. Ramaswamy et al., Radiative Forcing of Climate Change, in CLIMATE CHANGE 2001: THE SCIENTIFIC BASIS, CONTRIBUTION OF WORKING GROUP 1 TO THE THIRD ASSESSMENT REPORT OF THE INTERGOVERNMENTAL PANEL ON CLIMATE CHANGE 349, 397 (S. Solomon et al. eds., 2001) ("While the radiative forcing is generally negative, positive forcing occurs in areas with a very high surface reflectance such as desert regions in North Africa, and the snow fields of the Himalayas.").
43 Hearing, supra note 15, at 71 (statement of Charles Zender, Associate Professor, University of California at Irvine).
44 Quinn et al., supra note 20, at 1732.
46 Yun Qian et al.,
Effects of Soot-Induced Snow Albedo Change on Snowpack and Hydrological Cycle in Western United States Based on Weather Research and Forecasting Chemistry and Regional Climate Simulations, 114 J. GEOPHYSICAL. RES. D03108 at 2 (2009). 47 D. WALISER, ET AL., SIMULATING THE COLD SEASON SNOWPACK: THE IMPACT OF SNOW ALBEDO AND MULTI-LAYER SNOW PHYSICS vi (2009), http://www.energy.ca.gov/2009publications/CEC-500-2009-030/CEC-500-2009-030-F.PDF.
regions.41 For example, the International Panel on Climate Change reports that emissions from biomass burning, which usually have a negative forcing, have a positive forcing over snow fields in areas such as the Himalayas.42
Due to its short atmospheric lifespan, black carbon is not globally well-mixed. In most years, 70-90% of Arctic black carbon appears to stem from fuel combustion.43 Black carbon emissions deposited in the Arctic largely originate from Northern Eurasia, North America, and Asia.44 However, emissions of black carbon occurring within the Arctic have a disproportionately larger impact on Arctic warming than emissions generated elsewhere.45 As Arctic ice melts and shipping activity increases, emissions originating within the Arctic are expected to rise. In the Western United States, much of the black carbon deposition onto snow comes from populated regions west of the mountains, in particular from vehicular and ship emissions.46 Thus, "reductions in local emissions, which would provide an increase in snow albedo, could [partially] alleviate early snowmelt and reduce runoff in late winter and early spring caused by the global climate change."47D.
Strategies for Reducing Black Carbon Emissions
Based on the composition of major sources of black carbon emissions, measures to reduce black carbon should target sources that emit a high percentage of black carbon in comparison to cooling aerosols, such as emissions resulting from diesel combustion. Black carbon emissions emitted in the Arctic merit focused targeting because they have a disproportionate impact of Arctic warming and loss of sea ice. In addition, because sources that may typically result in negative forcing such as biomass burning can cause local positive forcing when proximate to snow and ice, reduction in emissions from these sources should also be considered. Although the United States has made substantial strides in regulating emissions from diesel combustion on public health grounds, thereby reducing black carbon, the United States has significant room to reduce black carbon emissions further. Recently summarized "no regrets" targets to mitigate the climate impacts of black carbon include: (1) diesel combustion in on-road heavy-duty vehicles,7
48 INTERNATIONAL COUNCIL ON CLEAN TRANSPORTATION, A POLICY-RELEVANT SUMMARY OF BLACK CARBON CLIMATE SCIENCE AND APPROPRIATE EMISSION CONTROL STRATEGIES 8 (2009) [hereinafter ICCT], http://www.theicct.org/documents/0000/1022/BC_policy-relevant_summary_Final.pdf
49 Quinn et al., supra note 20, at 1732.
50 James Corbett et al., Mortality from Ship Emissions: A Global Assessment, 44 ENVTL. SCI. & TECH. 8512, 8513 (2007).
51 ICCT, supra note 48, at 8.
52 The EPA received petitions from Earthjustice, Oceana, Friends of the Earth, and the Center for Biological Diversity, a second petition from the State of California, and a third petition from the South Coast Air Quality Management District.
53 The EPA received two petitions to regulate greenhouse emissions from nonroad engines and vehicles, the first from the States of California, Connecticut, Massachusetts, New Jersey and Oregon and Pennsylvania’s Department of Environmental Protection, and the second from the Western Environmental Law Center on behalf of the International Center for Technology Assessment, Center for Food Safety, and Friends of the Earth.
off-road engines, and commercial shipping, especially near the Arctic; (2) near-Arctic biomass burning from forest fires and controlled agricultural fires; (3) near-glacier emissions of biofuel burning in residential heating and cooking; and (4) low-sulfur coal combustion in residential heating and cooking and industrial brick kilns in the developing world.48
Reducing within-Arctic emissions of black carbon (e.g. generators) and implementing emission controls on marine vessels operating within Arctic waters, particularly in light of the likely increase in shipping activity as the snow/ice pack decreases, will be required to reduce Arctic warming.49 The replacement of marine residual oil with cleaner fuels, such as marine gas oil and marine diesel oil, will directly impact the black carbon, particulate organic matter, and sulfates attributed to ships.50 Strategies to address black carbon emissions from ships also include operational measures like speed controls and shore-power electrification in port.51 By promulgating regulations in response to the three Clean Air Act petitions that the Agency has before it to limit greenhouse gas and black carbon emissions from ships, and by mandating cleaner fuels for ships seeking to dock at U.S. ports, EPA can achieve significant reductions in the emissions of black carbon and other climate change pollutants.52
Recent EPA regulations on diesel emissions are expected to significantly reduce black carbon emissions from new heavy-duty vehicles. However, many of the standards in these rules do not phase in fully for new engines until 2015, with benefits accruing incrementally over a long period due to the slow turnover of older engines. Moreover, with the exception of rebuilt heavy duty engines, the rules do not require any additional black carbon emissions reductions in the existing, or "legacy," fleet of diesel vehicles, which have long life spans. Requiring regular vehicle emissions test, retirement, or retrofitting (e.g. particulate traps), including penalties for failing to meet air quality emissions standards, and heightened penalties for on-the-road "super-emitting" vehicles can achieve critically needed black carbon reductions from existing diesel powered vehicles. The EPA could also reduce black carbon emissions from off-road engines by responding to petitions for a rulemaking to reduce greenhouse pollution from these engines.538
54 See, e.g., Hearing, supra note 15, at 17 (statement of Mark Z. Jacobson, Professor, Stanford University).
55 Id. at 53 (statement of V. Ramanathan, Professor, University of San Diego).
56 Hansen & Nazarenko, supra note 16, at 423.
57 National Snow & Ice Data Center, Arctic Sea News & Analysis, Ice Extent Reaches Annual Maximum (2009), http://nsidc.org/arcticseaicenews/2009/030309.html.
Id. 60 Press Release, National Snow & Ice Data Center, Arctic Sea Ice Extent Remains Low; 2009 Sees Third-Lowest Mark (Oct. 6, 2009), available at http://nsidc.org/news/press/20091005_minimumpr.html.
Reducing Black Carbon Emissions is Critical to Avoiding Complete Loss of Summer Arctic Sea Ice
While reductions in carbon dioxide pollution are the backbone of any meaningful effort to mitigate the impacts of global warming, even if swift and deep reductions in carbon dioxide emissions are made, given the long lifetime of carbon dioxide in the atmosphere, these reductions may not be achieved in time to prevent the complete loss of summer sea ice in the Arctic and U.S. glaciers. Because black carbon emitted today will largely leave the atmosphere in a month or less, reducing black carbon emissions reduces warming within weeks.54 Major cuts in black carbon emissions could slow the effects of climate change for a decade or two, buying policy makers more time to cut carbon dioxide emissions and potentially avoid irreversible effects of global warming.55 Thus, restoration of snow albedos to levels approaching pristine pre-industrial values has the double benefit of reducing global warming and pushing back the point at which dangerous anthropogenic interference with the climate occurs.56V.
THE ATMOSPHERIC DEPOSITION OF BLACK CARBON ON SEA ICE AND GLACIERS IS SUBJECT TO REGULATION UNDER THE CLEAN WATER ACT
Sea Ice and Glaciers are Waters of the United States Afforded Protection Under the Clean Water Act
Sea ice is frozen seawater that floats on the ocean surface. Blanketing millions of square kilometers, sea ice forms and melts with the polar seasons, affecting both human activity and biological habitat. Arctic sea ice approaches its annual maximum in February.57 In February 2009, sea ice extended along the northern and western shores of Alaska.58 However, the monthly average sea ice extent for February 2009 was the fourth lowest in the satellite record, with February 2005 having the lowest extent, February 2006 the second lowest, and February 2008 the third lowest. Including 2009, the downward linear trend in February sea ice extent over the satellite record stands at -2.8 percent per decade.59 Arctic sea ice reaches its minimum extent in September. Sea ice extent in 2009 was the third lowest since the start of the satellite record in 1979, with the past five years having the five lowest sea ice extents on record.60 Nearly 40 percent of the sea ice area that was present in the 1970s was lost by 2007, the lowest year on
61 WORLD WILDLIFE FUND INT’L, ARCTIC CLIMATE FEEDBACKS: GLOBAL IMPLICATIONS 8 (Martin Sommerkorn & Susan Joy Hassol eds., 2009).
62 UNIV. OF NEW SOUTH WALES RESEARCH CENTRE, THE COPENHAGEN DIAGNOSIS, UPDATING THE WORLD ON THE LATEST CLIMATE SCIENCE 31 (2009); WORLD WILDLIFE FUND INT’L, supra note 61, at 8.
63 K. Stoeve et al, Arctic Sea Ice Extent Plummets in 2007, 89 EOS 13, 14 (Jan. 2008); see also M. Wang & J.E. Overland, A Sea Ice Free Summer Arctic Within 30 Years?, 36 GEOPHYSICAL. RES. LETTERS L07502 (2009) (predicting near ice-free Arctic by 2037).
64 Clean Water Act § 502(7), 33 U.S.C. § 1362(7) (2006).
65 Clean Water Act § 502(8), 33 U.S.C. § 1362(8) (2006).
66 Clean Water Act § 304(a)(2), 33 U.S.C. § 1314(a)(2) (2006) (emphasis added).
67 See, e.g., United States v. Hamel, 551 F.2d 107 (6th Cir. 1977) (affirming conviction for willful discharge of gasoline onto ice overlying lake).
68 See, e.g., EPA & Army Corps of Engineers, Clean Water Act Jurisdiction Following the U.S. Supreme Court’s Decision in Rapanos v. United States & Carabell v. United States (Dec. 2, 2008).
69 Quivira Mining Co. v. U.S. Envtl Prot. Agency, 765 F.2d 126, 130 (10th Cir. 1985) (citing United States v. Texas Pipe Line Co., 611 F.2d 345, 347 (10th Cir. 1979).
70 Clean Water Act § 101(a), 33 U.S.C. § 1251(a) (2006).
record.61 The observed summertime melting of Arctic sea ice has far exceeded the worst-case projections of climate models in the Fourth Assessment Report of the International Panel on Climate Change.62 Scientists now predict that a seasonally ice-free Arctic Ocean could be realized by 2030.63
Protection of sea ice falls within the jurisdiction of the Clean Water Act because the Act explicitly encompasses protection of territorial seas off the coast of Alaska where sea ice seasonally forms. "Navigable waters" is defined under the Act as "the waters of the United States, including the territorial seas."64 "Territorial seas" is in turn defined as belt of the seas measured from the line of ordinary low water along that portion of the coast which is in direct contact with the open sea and the line marking the seaward limit of inland waters, and extending seaward a distance of three miles."the "65 In addition, Section 304(a)(2) requires EPA to develop and publish information "on the factors necessary to restore and maintain the chemical, physical, and biological integrity of all navigable waters, ground waters, waters of the contiguous zone, and
the oceans." 66
While there has been little explicit discussion to date of specific protection for water in its solid form under the Act, courts have not distinguished between discharges of pollutants onto ice or water when enforcing the Clean Water Act.67 For purpose of the Clean Water Act, a "navigable water" need not be navigable in fact to be afforded the protections of the Act.68 Indeed, in passing the Clean Water Act, Congress did not intend to use the term "navigable waters" in the traditional sense, but to "extend the coverage of the act as far as permissible under the commerce clause." Accordingly, there is no legitimate basis to withhold Clean Water Act protection to sea ice because it is a solid. 69
Protection of sea ice also furthers the purpose of the Clean Water Act, which is "to restore and maintain the chemical, physical, and biological integrity of the Nation’s waters."70 Sea ice is a fundamental component of the Arctic marine ecosystem. For example, the volume and timing of sea ice melt is intimately connected to the chemical, physical and biological integrity of Arctic waters. Sea ice impacts the physical integrity of Arctic waters through alterations in temperature and light. The Arctic food web is