BEFORE THE ENVIRONMENTAL PROTECTION AGENCY 

PETITION FOR RULEMAKING PURSUANT TO SECTION 21 OF THE TOXIC 

SUBSTANCES CONTROL ACT, 15 U.S.C. § 2620, CONCERNING 

THE REGULATION OF CARBON DIOXIDE 

Credit: NOAA 

CENTER FOR BIOLOGICAL DIVERSITY 

DONN J. VIVIANI, PhD 

PETITIONERS 

June 30, 2015 
i 

NOTICE OF PETITION

Gina McCarthy 

Administrator 

U.S. Environmental Protection Agency 

1200 Pennsylvania Avenue, N.W. 

Washington, D.C. 20460 

Email: McCarthy.Gina@epa.gov 

PETITIONERS 

Center for Biological Diversity 

1212 Broadway #800 

Oakland, CA 94612 

(510) 844-7100 

Donn J. Viviani, PhD 

4907 Yorktown Blvd 

Arlington, VA 22207 

oceanpetition@gmail.com 

The Center for Biological Diversity (“Center”) is a non-profit, public interest environmental 

organization dedicated to the protection of native species and their habitats through science, 

policy and environmental law. The Center has over 800,000 members and online activists 

throughout the United States and around the world. The Center’s Oceans Program and its 

supporters are specifically concerned with the conservation of marine species, the preservation of 

ocean ecosystems and the effective implementation of U.S. environmental laws, including the 

Toxic Substances Control Act. The Center submits this petition on its own behalf and on behalf 

of its members and staff with an interest in protecting the marine environment. 

Donn J. Viviani, PhD, is a retired U.S. Environmental Protection Agency scientist. He was the 

Director of the Climate Policy Assessment Division in the Office of Policy, Economics and 

Innovation. He also served as Chairman of the Great Lakes Water Board's Toxic Substances 

Committee and as a member of the Science Coordinating Committee for the International Joint 

Commission for the Great Lakes. Dr. Viviani enjoys the ocean and submits this petition, in part, 

so his grandchildren will be able to enjoy it as well. Dr. Viviani also submits a supplement to the 

petition, under his signature only, and respectively requests that it be considered. 

ACTION REQUESTED 

Pursuant to section 21 of the Toxic Substances Control Act (“TSCA” or the “Act”), 15 

U.S.C. § 2620, and section 553(e) of the Administrative Procedure Act (“APA”), 5 U.S.C. § 

553(e), the Center for Biological Diversity and Donn J. Viviani (collectively, “Petitioners”) 

hereby petition the Administrator of the U.S. Environmental Protection Agency (“EPA”) to 

promulgate regulations protecting public health and the environment from the serious harms 

associated with anthropogenic emissions of carbon dioxide, including ocean acidification. 

Specifically, Petitioners request that EPA adopt a rule under section 6 of the Act, 15 U.S.C. § 

2605, requiring manufacturers and processors to mitigate these emissions. 

 This petition sets in motion a specific process, placing definite response requirements on 

EPA. Specifically, TSCA stipulates that the agency “shall either grant or deny the petition” 

within 90 days following its receipt, “promptly commenc[ing] an appropriate [rulemaking] 
ii 

proceeding” if such action is warranted. 15 U.S.C. § 2620(b)(3) (emphasis added). Conversely, 

should EPA deny this petition, the agency must publish the reasons for denial in the Federal 

Register. 15 U.S.C. § 2620(b)(3); see also 5 U.S.C. § 555(e) (“Prompt notice shall be given of 

the denial in whole or in part of a written application, petition, or other request of an interested 

person made in connection with any agency proceeding.”). Pursuant to 15 U.S.C. § 2620(b)(4), 

petitioners may file suit in federal district court to challenge an adverse or untimely 

determination. See also 5 U.S.C. §§ 702, 706. 

 As described in this petition, anthropogenic emissions of carbon dioxide satisfy the 

standard for regulation set forth at 15 U.S.C. § 2605. For example, EPA has acknowledged that 

these emissions have the potential to alter ocean chemistry, thus imperiling important marine 

ecosystems and presenting an unreasonable risk of injury to the environment. Accordingly, the 

agency must promptly commence the proposed rulemaking to reduce and mitigate these harms. 

In the event that EPA concludes that there are insufficient data and experience upon which to 

determine or predict the effects of carbon dioxide emissions, we alternatively request that the 

agency adopt a rule under section 4 of the Act, 15 U.S.C. § 2603, requiring manufacturers and 

processors responsible for the generation of carbon dioxide to undertake testing to determine 

toxicity, persistence, and other characteristics which affect health and the environment and are 

necessary to determine if there is an unreasonable risk of injury to health or the environment. 

Dated this 30th day of June 2015. 

/s/ Miyoko Sakashita

Miyoko Sakashita, Oceans Director 

Center for Biological Diversity 

1212 Broadway #800 

Oakland, CA 94612 

(510) 844-7100 

miyoko@biologicaldiversity.org 

/s/ Donn Viviani

Donn J. Viviani, PhD 

4907 Yorktown Blvd 

Arlington, VA 22207 

oceanpetition@gmail.com 

 
iii 

TABLE OF CONTENTS 

INTRODUCTION .......................................................................................................................... 1

I. The Toxic Substances Control Act ..................................................................................... 2

II. EPA Must Issue a Rule to Regulate or Require Tests for CO2 Causing Ocean 

Acidification ............................................................................................................................... 3

A. TSCA Authorizes EPA to Act on CO2 ........................................................................... 3

1. CO2 Is a Chemical Substance ..................................................................................... 4

2. CO2 Is in Commerce ................................................................................................... 4

B. EPA Should Initiate Rulemaking to Control CO2 under TSCA ..................................... 6

1. CO2 Pollution Presents an Unreasonable Risk of Injury to the Environment............. 7

a. CO2 Causes Irreversible Ocean Acidification ....................................................... 7

i. What Is Ocean Acidification ............................................................................. 8

ii. Observed and Predicted Acidification ............................................................... 9

iii. CO2 Kills and Injures Marine Life .................................................................. 12

b. High-CO2 Waters Injure the Growth, Survival, Fitness, and Reproduction of 

Marine Animals ............................................................................................................ 13

i. Molluscs, Echinoderms, and Crustaceans ....................................................... 13

ii. Corals ............................................................................................................... 17

iii. Plankton ........................................................................................................... 23

iv. Cephlopods and Fish ....................................................................................... 24

c. Other Environmental Impacts of Ocean Acidification ........................................ 25

i. Increased Toxicity of Harmful Algal Blooms and Sediments ......................... 25

ii. Noise Pollution Increases in Low pH Waters .................................................. 26

d. Ocean Acidification’s Ecosystem Impacts .......................................................... 26

2. Risk Reduction Costs and Benefits ........................................................................... 27

a. Socioeconomic Costs of Ocean Acidification ..................................................... 27

b. Risk Reduction Methods ..................................................................................... 29

c. Social Costs of Carbon ........................................................................................ 31

C. Alternatively, EPA Must Require Testing to Develop Adequate Data ........................ 35

1. CO2 May Present an Unreasonable Risk .................................................................. 35

2. Substantial Quantities of CO2 Are Released into the Environment .......................... 35

3. Recommendations for Testing .................................................................................. 36

D. Inadequacy of Existing CO2 Reduction Strategies ....................................................... 37

1. Global Greenhouse Gas Emissions Are Increasing Substantially ............................ 37
iv 

2. U.S. Measures to Reduce Greenhouse Gas Emissions Are Insufficient ................... 38

3. International Measures to Reduce Greenhouse Gas Emissions Are Inadequate ...... 39

CONCLUSION ............................................................................................................................. 40

BIBLIOGRAPHY ......................................................................................................................... 41
1 

INTRODUCTION 

Ocean acidification — caused by carbon dioxide (“CO2”) emissions — is a severe threat to the 

marine environment and the health of people who depend on oceans and coasts. Because of the 

unreasonable risk that CO2 poses to the environment and human health, this petition seeks 

rulemaking under the Toxic Substances Control Act (“TSCA”) to regulate CO2 from cradle to 

grave. 

About 28% of CO2 emissions from power generation, cement production, industry, and other 

sources are absorbed by the ocean. These CO2 emissions cause seawater to become more acidic 

and corrosive to sea life. Anthropogenic CO2 emissions have increased the acidity of the oceans 

on average by 30%, and by the end of the century scientists predict that the oceans will become 

150-170% more acidic. 

While the most dangerous consequences of CO2 on our oceans are still to come, harmful impacts 

on the environment are already well-documented. 

 Billions of oyster larvae have perished in the Pacific Northwest due to ocean 

acidification; 

 53% of pteropods, plankton that form the base of the marine food web, along the West 

Coast have severely dissolved shells because of the corrosive nearshore conditions; and 

 Calcification rates at coral reef locations in the western tropical Pacific and the Caribbean 

may have already declined by 15%. 

These are just some of the harmful environmental impacts of ocean acidification caused by CO2

emissions. Anthropogenic CO2 emissions are contributing to increasingly corrosive conditions 

for marine animals, and will continue to grow more severe absent actions to promptly reduce 

CO2 pollution in the atmosphere. 

 

TSCA was enacted in part to address the threat of ozone depletion caused by chlorofuorocarbon 

(CFC) emissions. And here again TSCA regulation is needed where airborne emissions are 

causing damage to our environment — this time threatening ocean ecosystems, fish and shellfish 

industries, and communities that depend on oceans and coral reefs. 

Petitioners specifically request that EPA take the following actions: 

1. Make a determination under TSCA § 6 that CO2 presents an unreasonable risk of 

injury to health or the environment; and 

2. Initiate rulemaking to control CO2; or 

3. If EPA finds data inadequate to make a §6 determination then EPA must initiate 

rulemaking for testing under TSCA § 4. 

This petition presents scientific evidence that establishes that CO2 presents an unreasonable risk 

of injury to the environment, and therefore EPA must take action under TSCA section 6. 
2 

I. The Toxic Substances Control Act 

Congress enacted TSCA, 15 U.S.C. §§ 2601 et seq., “to assure that ... innovation and commerce 

in ... chemical substances and mixtures do not present an unreasonable risk of injury to health or 

the environment.”1

 Accordingly, lawmakers required those responsible for the manufacture and 

processing of these compounds to develop “adequate data” describing their effects, and 

authorized EPA to devise and implement reasonable controls to prevent the risk of injury to 

health or the environment.2

Section 6 of TSCA mandates that EPA “shall” regulate a chemical substance for which 

there is a reasonable basis to conclude that the manufacture, processing, distribution 

in commerce, use, or disposal of a chemical substance or mixture, or that any 

combination of such activities, presents or will present an unreasonable risk of injury 

to health or the environment.3

 

Permissible regulations include requirements prohibiting or “limiting the amount of such 

substance ... which may be manufactured, processed, or distributed in commerce.”4 EPA can 

also require processors “to give public notice of such risk [of injury], and . . . to replace or 

repurchase such substance . . . to adequately protect health or the environment.”5 In assessing 

risk, EPA must consider: 

(A)the effects of such substance or mixture on health and the magnitude of the exposure 

of human beings to such substance or mixture, 

(B) the effects of such substance or mixture on the environment and the magnitude of the 

exposure of the environment to such substance or mixture, 

(C) the benefits of such substance or mixture for various uses and the availability of 

substitutes for such uses, and 

(D)the reasonably ascertainable economic consequences of the rule, after consideration 

of the effect on the national economy, small business, technological innovation, the 

environment, and public health.6

Thus, if there is a reasonable basis to conclude that a proposed rule is necessary to protect the 

environment, then EPA must grant a petition for rulemaking and initiate rulemaking procedures. 

Factual certainty is not required; instead, the agency may “base its action on scientific theories, 

consideration of projections from available data, modeling using reasonable assumptions, and 

extrapolations from limited data.”7 Even if EPA determines that another federal law “could 

 

1

 15 U.S.C. § 2601(b)(3) (2012). Within the meaning of TSCA, the term “chemical substance” includes “any 

organic or inorganic substance of a particular molecular identity.” Id. § 2602(2). 2 Id. § 2601(b)(1) & (2). 3 Id. § 2605(a) (emphasis added). 4 Id. § 2605(a)(1)(B). 5 Id. § 2605(b)(2)(B). 6 Id. § 2605(c)(1). E. 7

 Lead Fishing Sinkers; Response to Citizens’ Petition and Proposed Ban, 59 Fed. Reg. 11,122, 11,138 (Mar. 9, 

1994) (citing H.R. Rep. No. 1341, 9th Cong., 2d Sess. 32 (1976)). 
3 

[sufficiently] eliminate[] or reduce[]” the risk associated with a particular chemical substance, 

the agency may elect to regulate the substance under TSCA, provided that a “comparison of the 

estimated costs” and “relative efficiency” reveals that such action promotes the public interest.8

 

In the event that EPA lacks adequate data and experience upon which to determine the health and 

environmental risks associated with a particular chemical substance, the agency “shall by rule 

require that testing be conducted on such substance.”9 Specifically, Section 4 of the Act 

authorizes EPA to compel manufacturers and processors to evaluate the safety of substances that 

“may present an unreasonable risk of injury to health or the environment” or that “[are] or will 

be produced in substantial quantities” and, thus, “may reasonably be anticipated to enter the 

environment in substantial quantities” or result in “significant or substantial human exposure.”10

TSCA provides for testing to determine toxicity, persistence, and other characteristics which 

affect health and the environment and are necessary to determine if there is an unreasonable risk 

of injury to health or the environment. 

Over forty years ago, the Council on Environmental Quality warned of the “high priority need” 

for a new legal authority capable of ensuring the safe use of toxic chemicals.11 Despite TSCA’s 

powerful potential, however, EPA has accomplished very little under the Act. This petition 

presents substantial scientific evidence demonstrating that anthropogenic emissions of CO2 pose 

an unreasonable risk to human and environmental health. Indeed, studies show that significant 

and potentially irreversible harm has already occurred. As the Council recognized decades ago, 

“[w]e should no longer be limited to repairing [this] damage after it has been done; nor should 

we continue to allow the entire population or the entire environment to be used as a laboratory.” 

Instead, EPA must take prompt action to reduce and mitigate the anthropogenic production of 

CO2. 

II. EPA Must Issue a Rule to Regulate or Require Tests for CO2 Causing Ocean 

Acidification 

CO2 presents an unreasonable risk of injury to the environment because its exposure to the ocean 

changes seawater chemistry with harmful impacts on marine life and ecosystems. Substantial 

evidence supports this conclusion and is discussed in this petition. Accordingly, this petition 

seeks a rulemaking to regulate CO2 under TSCA. 

This petition requires EPA to make a determination under TSCA section 6 if the injury to the 

environment and health from CO2 is unreasonable. Alternately, if the Agency demonstrates that 

the existing science is insufficient to make a determination under TSCA section 6, EPA must 

initiate test rules under TSCA section 4 to develop the missing information needed to determine 

if the TSCA section 6 trigger is met and how best to mitigate the harm. 

A. TSCA Authorizes EPA to Act on CO2 

To enable the achievement of TSCA’s ambitious objectives, Congress broadly defined EPA’s 

jurisdiction under the Act. As described above, TSCA explicitly directs EPA to initiate 

 

8 Id.

9 Id. § 2603 (emphasis added). 10 Id. 11 Council on Envtl. Quality, Toxic Substances at v (April 1971). 
4 

rulemaking upon finding that “the manufacture, processing, distribution in commerce, use, or 

disposal of a chemical substance” threatens public health or the environment.12 TSCA then 

authorizes the regulation of “chemical substances” that are “in commerce,” a test met by CO2. 

Indeed, CO2 is already on the TSCA inventory as a “chemical in commerce.”13 CO2 necessarily 

qualifies as a “chemical substance,” a category that includes “any organic or inorganic substance 

of a particular molecular identity.”14 Moreover, the anthropogenic emissions at issue are in 

commerce; federal courts have previously concluded that air emissions15 and “incidental 

byproducts of industrial chemical processes” are within the scope of EPA’s authority under the 

Act.16 Existing scientific evidence demonstrates that the anthropogenic production of CO2 has 

already damaged marine ecosystems and endangered vulnerable portions of the human 

population. For the reasons described below, EPA must promptly reduce and mitigate these 

harms. 

 

1. CO2 Is a Chemical Substance 

First, carbon dioxide is a “chemical substance” falling within the scope of the Act. The Act 

defines “chemical substance” as “any organic or inorganic substance of a particular molecular 

identity, including any combination of such substances occurring in whole or in part as a result 

of a chemical reaction or occurring in nature and (ii) any element or uncombined radical.”17. CO2

meets this definition. CO2 is a chemical substance that occurs both in nature and as a result of a 

chemical reaction. It consists of a carbon atom bonded to two oxygen atoms: 

O=C=O 

It is identified by molecular formula CO2 and by CAS number 124-38-9. 

2. CO2 Is in Commerce 

Second, CO2 is in commerce, and it is already on the TSCA inventory (CAS 124-38-9) with 

“chemical in commerce” as the stated reason for regulation.18 Under TSCA’s statutory text, 

“commerce” is defined as “trade, traffic, transportation, or other commerce . . . between a place 

in a State and any place outside of such state, or . . . which affects trade, traffic, transportation, 

or commerce.”19 CO2 is primarily produced as a byproduct from the combustion of fossil fuels; 

according to the EPA, CO2 emissions account for 77% of greenhouse gas emissions worldwide.20

 

12 Id. §§ 2605(a), 2603(a)(1)(A)(i), 2506(a). Although TSCA does not define “disposal,” other federal environmental 

laws explain that this term encompasses “the discharge, deposit, injection, dumping, spilling, leaking, or placing of 

any solid waste or hazardous waste into or on any land or water so that such solid waste or hazardous waste or any 

constituent thereof may enter the environment or be emitted into the air or discharged into any waters, including 

ground waters.” 42 U.S.C. §§ 6903(3), 9601(29). 

13 EPA, Substance Registry at http://1.usa.gov/1IBS1w6 (last accessed June 28, 2015). 14 15 U.S.C. § 2602(2). This definition excludes specific compounds already subject to federal control, such as 

pesticides, tobacco products, nuclear materials and food, drugs and cosmetics. Id. § 2602(2)(B). 15 Citizens for a Better Env’t v. Thomas, 704 F. Supp. 149, 152 (E.D. Ill. 1989). 16 Envtl. Def. Fund v. Envtl. Prot. Agency, 636 F.2d 1267, 1271 (D.C. Cir. 1980). 17 15 U.S.C. § 2602(2)(A). 

18 EPA, Substance Registry at http://1.usa.gov/1IBS1w6. 19 15 U.S.C. § 2602(3). 

20 EPA, Global Greenhouse Gas Emissions Data, http://www.epa.gov/climatechange/ghgemissions/global.html (last 

updated June 21, 2013; last accessed June 28, 2015). 
5 

The most voluminous sources of greenhouse gas emissions are energy suppliers,21 industry,22

land use and forestry,23 agriculture,24 transportation,25 commercial and residential buildings,26

and waste and wastewater.27 All of these emitters produce CO2 as a byproduct of their ordinary 

processes. 

TSCA’s statutory and regulatory text support the proposition that CO2 emitted as a byproduct of 

industrial processes can be regulated under TSCA because CO2 in this context is manufactured, 

meaning “produce[d] . . . with the purpose of obtaining an immediate or eventual commercial 

advantage.”28 All of the industries listed above which emit CO2 are performed to obtain an 

immediate or eventual commercial advantage, as all of these industries are commercial and part 

of a competitive market. Therefore, incidental production of CO2 is manufactured or produced 

“for a commercial purpose,” and is found “in commerce” pursuant to TSCA regulations. 

 Accordingly, CO2 emissions fit the regulatory definition of a chemical substance produced for a 

commercial purpose. This is bolstered by the broad definition of “commerce” in the TSCA 

statute; at the very least, CO2 emissions “affect” trade, traffic, transportation, and commerce. 

TSCA’s purpose and regulatory text support the regulation of chemical substances that are an 

incidental byproduct, and indeed EPA has regulated chemical byproducts under TSCA before. 

For example, PCBs are regulated under TSCA even when they are only incidentally produced as 

a byproduct of industrial processes.29 EPA regulates PCB “byproducts” for which there are no 

separate commercial intents, and TSCA regulates inadvertently vented PCB emissions.30

Moreover, EPA’s authority under TSCA broadly defines what it regulates under “disposal” of 

PCBs to include intentional and accidental disposal.31 EPA has also previously prohibited wastes 

from chemical manufacturing under TSCA.32

 

21 Which emit greenhouse gases through “[t]he burning of coal, natural gas, and oil for electricity and heat.” Id. 22 Which emit greenhouse gases through “fossil fuels burned on-site at facilities for energy” and “chemical, 

metallurgical, and mineral transformation processes not associated with energy consumption.” Id. 23 Which emit “carbon dioxide . . . from deforestation, land clearing for agriculture, and fires or decay of peat soils.” 

Id. 24 “Greenhouse emissions from agriculture mostly come from the management of agricultural soils, livestock, rice 

production, and biomass burning.” Id. 25 Which emit greenhouse gases through “fossil fuels burned for road, rail, air, and marine transportation.” Id. 26 Which emit greenhouse gases from “on-site energy generation and burning fuels or heat in buildings or cooking in 

homes.” Id. 27 Which emit carbon dioxide through the “incineration of some waste products that were made with fossil fuels, 

such as plastics and synthetic textiles.” Id. 28 40 C.F.R. § 710.3; 40 C.F.R. § 704.3 (“Manufacture for commercial purposes also applies to substances that are 

produced coincidentally during the manufacture, processing, use, or disposal of another substance or mixture, 

including both byproducts that are separated from that other substance or mixture and impurities that remain in that 

substance or mixture. Such byproducts and impurities may, or may not, in themselves have commercial value. They 

are nonetheless produced for the purpose of obtaining a commercial advantage since they are part of the 

manufacture of a chemical product for a commercial purpose.”). 29 44 Fed. Reg. 31525 (May 31, 1979); 40 C.F.R. § 761. 

30 See, e.g., 40 C.F.R. Part 761. 31 40 C.F.R. § 761.3. 

32 45 Fed. Reg. 592 (March 11, 1980);40 C.F.R. § 775 (1980) (prohibiting disposal of 2,3,7,8-tetracholorodibenzo-pdioxin (TCDD) a manufacturing waste). 
6 

Further, CO2 emissions are in commerce as they are traded, bought, and sold as carbon offsets. 

CO2 is also produced for commerical purposes including for uses in fertilizer, beverage 

carbonation, dry ice, refrigeration, pressurization, fire extinguishment, and packaging. 

B. EPA Should Initiate Rulemaking to Control CO2 under TSCA 

Petitioners request that EPA make finding that CO2 presents or will present an unreasonable risk 

of injury to the environment or health. TSCA requires that EPA “shall” initiate rulemaking upon 

finding “a reasonable basis to conclude that the manufacture, processing, distribution in 

commerce, use or disposal of a chemical substance of mixture ... presents or will present an 

unreasonable risk of injury to health or the environment.”33 

 

The information and supporting documents provided in this petition indicate that CO2 is already 

causing injury to the environment due to ocean acidification. The scientific evidence further 

supports that the injury to the environment and health will grow more severe as CO2 pollution 

continues. EPA cannot deny that CO2 is harming the environment. Indeed, EPA acknowledges 

that ocean acidification poses risk: 

Ocean acidification, like Climate change is primarily caused by increasing carbon 

dioxide (CO2) concentrations in the atmosphere. As a result of absorbing large 

quantities of human made CO2 emissions the ocean chemistry is changing, which 

is likely to negatively affect important marine ecosystems and species including 

coral reefs, shellfish, and fisheries. 

 (Environmental Protection Agency 2010). 

EPA must find that such injury is an unreasonable risk.34 While Congress did not define 

the phrase “unreasonable risk,” EPA has interpreted relevant legislative history to require 

that the agency: 

balance the benefits derived from risk reduction against the social and economic 

costs incurred, taking into account such factors as the extent and magnitude of 

risk posed; the societal consequences of removing or restricting use of products; 

availability and potential hazards of substitutes; and impacts on industry, 

employment, and international trade.35 

No specific factual determination is necessary to establish “unreasonable risk.” For 

example, even under the stricter standard of 15 U.S.C. § 2606, EPA need not present 

evidence of actual injury before obtaining emergency injunctive relief to control 

“immanently hazardous chemical substance[s] or mixture[s].”36 For the reasons discussed 

below, application of the agency’s balancing test supports the additional regulation of 

CO2. 

 

33 15 U.S.C. § 2605(a). 

34 Id. 35 EPA, Guidance for Petitioning the Environmental Protection Agency Under Section 21 of the Toxic Substances 

Control Act, 50 Fed. Reg. 46,825 (Nov. 13, 1985). 

36 See H.R. Conf. Rep. No. 94-1679 78 (1976). 
7 

According to scientific experts: “Reducing CO2 emissions is the only way to minimise [sic] longterm, large-scale risks” (IBGP et al. 2013). 

1. CO2 Pollution Presents an Unreasonable Risk of Injury to the 

Environment 

There is clear consensus among leading national and international scientific bodies that 

anthropogenic CO2 causes changes in ocean chemistry that harm the marine environment. The 

Intergovernmental Panel on Climate Change (“IPCC”) determined that human sources of CO2

have caused a significant decline in surface ocean pH (Rhein et al. 2013), and over 90 national 

academies of sciences, including the United States’, have signed a statement that ocean 

acidification will “cause grave harm to important marine ecosystems as CO2 concentrations 

reach 450 ppm and above” (Interacademy Panel 2009). The Interacademy Panel concluded that 

CO2 has increased ocean acidity with “potentially profound consequences for marine plants and 

animals” including severe threats to coral reefs, polar ecosystems, and a likely reduction in 

marine food supplies (Id.). The National Research Council also acknowledges that “existing data 

support a growing consensus in the research community that most documented responses to 

acidification reflect impairment of physiological capacity or performance” for marine life with 

likely substantial socioeconomic impacts (National Research Council 2013). The U.S. National 

Climate Assessment concluded that ocean acidification will alter marine ecosystems in dramatic 

ways including threatening coral reef habitats and causing reduced growth and survival of 

shellfish in all regions (Doney et al. 2014). 

EPA acknowledges that “ocean acidification presents a suite of environmental changes that 

would likely negatively affect ocean ecosystems, fisheries, and other marine resources.” 75 Fed. 

Reg. 13538 (Mar. 22, 2010). EPA previously concluded that greenhouse gases, including CO2, 

endanger public health and the environment in part because of ocean acidification.37 

There is no doubt that CO2 pollution is changing ocean chemistry and harming the marine 

environment. Unabated, there will be severe and detrimental impacts on marine ecosystems, the 

economy, and public health. Accordingly, EPA must find that CO2 poses an unreasonable risk to 

the environment and health. 

a. CO2 Causes Irreversible Ocean Acidification 

Ocean acidification is a major threat to the marine environment. The oceans have absorbed CO2 

emitted into the atmosphere from power plants, manufacturing, cement production, and land use 

changes. Between 1750 and 2011, human activities have released 375 gigatons of carbon into the 

atmosphere, and approximately half of that has been absorbed by the oceans (Rhein et al. 2013). 

Each day about 22 million metric tons of CO2 is taken up by the oceans (Feely et al. 2008). This 

uptake of CO2 is changing ocean chemistry, causing the oceans to become more acidic. Since the 

industrial revolution surface ocean pH has declined by 0.11 units on average, corresponding with 

 

37 EPA, Endangerment and Cause or Contribute Findings for Greenhouse Gases under Section 202(a) of the Clean 

Air Act 80 (Dec. 7, 2009). 
8 

a 30% increase in acidity (Orr et al. 2005; Caldeira & Wickett 2005).38 If emissions continue 

unabated, ocean acidity will increase up to 170% by the end of the century (IBGP et al. 2013). 

Figure 1. Time series of atmospheric CO 2 at Mauna Loa (ppmv) and surface ocean pH and pCO2 

(μatm) at Ocean Station Aloha in the subtropical North Pacific Ocean (see inset map). Note that 

the increase in oceanic CO 2 over the period of observations is consistent with the atmospheric 

increase within the statistical limits of the measurements. (Feely et al. 2009). 

Anthropogenic ocean acidification exceeds the trend in natural variability significantly, up to 30 

times in some regions (Friedrich et al. 2012). The rate of change in ocean acidity is 

unprecedented in the past 300 million years, a period that includes four mass extinctions 

(Honisch et al. 2012; Zeebe 2012). The seawater chemistry change is an order of magnitude 

faster than what occurred 55 million years ago during Paleocene-Eocene Thermal Maximum, 

which is considered to be the closest analogue to the present, and during that period 96% of 

marine species went extinct (Id.). The current changes in seawater chemistry are irreversible on 

human timescales (Royal Society 2005). 

CO2’s impact on ocean chemistry is fundamentally altering the marine environment with 

negative impacts on marine species, habitats and ecosystems. 

i. What Is Ocean Acidification 

When the ocean absorbs CO2 from the atmosphere it changes ocean chemistry. CO2 that is 

absorbed by seawater reacts to form carbonic acid, which dissociates to form bicarbonate and 

releases hydrogen ions. This reaction reduces the amount of carbonate ions and decreases pH. 

The oceans store a significant amount of the CO2 pollution from human activities (Royal Society 

2005). While this has provided society with an important service of buffering against climate 

change impacts, it comes at a cost to the marine environment. 

 

38 Because the pH scale is logarithmic a small decrease is a significant change in acidity; for example, a decrease of 

0.1 pH is an approximate 30 percent increase in acidity. 
9 

Globally, surface water pH has declined 0.11 units on average between 1750 and 1994 (Sabine et 

al. 2004). Long-term monitoring has documented the impact of increasing atmospheric CO2 on 

declining seawater pH in the Pacific and Atlantic Oceans (see Figure 2). Results from time-series 

stations in the North Atlantic and North Pacific show a decrease of about 0.002 pH per year 

(Rhein et al. 2013). 

Figure 2. Long-term trends of surface seawater pH at three subtropical ocean time series in the 

North Atlantic and North Pacific Oceans, including (a) Bermuda Atlantic Time-series Study 

(BATS, 31°40’N, 64°10’W; green) and Hydrostation S (32°10’, 64°30’W) from 1983 to present 

(updated from Bates, 2007); (b) Hawaii Ocean Time-series (HOT) at Station ALOHA (A Longterm Oligotrophic Habitat Assessment; 22°45’N, 158°00’W; orange) from 1988 to present 

(updated from Dore et al., 2009) and (c) European Station for Time series in the Ocean (ESTOC, 

29°10’N, 15°30’W; blue) from 1994 to present (updated from González-Dávila et al., 2010). 

Atmospheric pCO2 (black) from the Mauna Loa Observatory Hawaii is shown in the top panel. 

Lines show linear fits to the data, whereas Table 3.2 give results for harmonic fits to the data 

(updated from Orr, 2011).(Rhein et al. 2013)

Ocean acidification not only makes the oceans more acidic, but it also reduces the amount of 

carbonate ions available for animals to build the shells and skeletons they need to survive. 

Carbonate is an important constituent of seawater because many organisms form their shells and 

skeletons by complexing calcium and carbonate. Waters that are supersaturated with aragonite 

are generally good for shell-building, while undersaturated waters (<1.0 Ωar) are corrosive to 

some marine animals. Corals require supersaturated waters above 3.3 Ωar (Meissner et al. 2012). 

Globally, there has been a decrease of about -0.4 Ωar (Gruber et al. 2012). The aragonite 

saturation state has declined 16% since the Industrial Revolution due, in large part, to 

anthropogenic CO2 (Feely et al. 2012a; Ishii et al. 2011). Modeling of the oceans’ aragonite 

saturation predicts that by the end of the century up to 75% of ocean volume could be 

undersaturated with respect to aragonite (Joos et al. 2011). 

ii. Observed and Predicted Acidification 

CO2 has already had measurable impacts on seawater chemistry. Some regions, such as those 

with upwelling systems or high latitudes, are especially vulnerable to ocean acidification. 
10 

1. Pacific Coast 

The West Coast is already experiencing adverse impacts of ocean acidification. As early as 2008, 

a survey off the coasts of Washington, Oregon, and California revealed that this region is already 

experiencing corrosive waters not expected until mid-century (See figure 3) (Feely 2008). 

Researchers found seawater undersaturated with respect to aragonite upwelling onto large 

portions of the continental shelf, reaching shallow depths of 40 to 120 meters (Id.). According to 

the study, the waters were last at the surface approximately 50 years ago when atmospheric CO2

concentrations were much lower (Feely et al. 2008). Feely et al. report that in the Pacific Ocean 

there has been a decrease of the saturation state of surface seawater with respect to aragonite and 

calcite as well as an upward shoaling of the saturation horizon by about 1-2 meters per year on 

average, due in large part to anthropogenic CO2 (R. A. Feely, Sabine, et al. 2012). As a result, 

marine organisms in surface waters, in the water column, and on the sea floor along the West 

Coast of the United States are already being exposed to corrosive water during the upwelling 

season. 

Modeling of the California Current System demonstrates that the area is rapidly approaching 

year-round undersaturation with respect to aragonite and it is departing significantly from natural 

variability (Hauri et al. 2013). Time series monitoring shows that the aragonite saturation state 

along the California coast is much lower than would be expected in the North Pacific (Harris, 

DeGrandpre et al. 2013). Surface Ωar values ranged between 0.66 and 3.9 compared to an 

estimated pre-industrial range of 1.0 to 4.7. While some areas, like Puget Sound, already exhibit 

undersaturated conditions every year (Feely, Klinger, et al. 2012; Reum et al. 2014), scientists 

predict that most shallow shelf areas along the West Coast will become undersaturated with 

respect to aragonite within the next 20-30 years (Capone & Hutchins 2013; Gruber et al. 2012). 
11 

Figure 3. Distribution of the depths of the undersaturated water (aragonite saturation < 1.0; pH < 

7.75) on the continental shelf of western North America from Queen Charlotte Sound, Canada, to 

San Gregorio Baja California Sur,Mexico. On transect line 5, the corrosive water reaches all the 

way to the surface in the inshore waters near the coast. The black dots represent station locations 

(Feely et al. 2008). 

2. Alaskan Waters 

High latitude waters are the “bellwether” of ocean acidification because these will be the first 

ocean regions to become persistently undersaturated with respect to aragonite as a result of 

greenhouse gas pollution (Fabry et al. 2009; Steinacher et al. 2009). High-latitude waters have 

naturally lower carbonate ion concentrations and saturation states due to a combination of cold 

temperatures which increase the solubility of CO2 and ocean mixing patterns (Fabry et al. 2009; 

Mathis et al. 2011a). As early as 2016, 10% of Arctic surface waters are expected to be 

undersaturated with respect to aragonite for at least one month per year (Steinacher et al. 2009). 

Recent observations of calcium carbonate saturation states in the North Pacific and Bering Sea 

have found that full water column undersaturation of calcium carbonate due to ocean 

acidification is already prevalent. Mathis et al. (2011a) reported that extensive areas of bottom 

waters over the Bering Sea shelf are becoming undersaturated with respect to aragonite for at 

least several months (July to September), and some areas of bottom water were already observed 

to be undersaturated with respect to calcite (Fabry et al. 2009, Mathis et al. 2011a). 
12 

Scientists predict that polar waters will be corrosive to shellbuilding animals within decades 

(IBGP et al. 2013). A 2015 study of observations in the Chukchi and Beaufort Seas in the Arctic 

indicates that within 15 years waters will become so corrosive that it will be difficult for marine 

animals to build and maintain their shells (Mathis et al. 2015). The highly productive fisheries of 

Alaska are in some of the most rapidly changing seawater conditions (Mathis et al. 2014). 

3. Sub-tropical Waters 

Subtropical waters have experienced declining saturation states due to ocean acidification. 

Within decades, scientists believe that ocean acidification will impair coral growth (IBGP et al. 

2013). Models show that by the end of the century, most coral reef areas will no longer have 

aragonite saturation states that are optimal for coral growth. A 10-year study of the Caribbean 

region found a strong regional decrease in aragonite saturation state between 1996-2006, from 

4.05 to 3.9, resulting from CO2 (Gledhill et al. 2008). Modeling predicts that under various 

emissions scenarios the coral reefs in the Caribbean will be thermally and chemically stressed 

between now and 2030 (Meissner et al. 2012). Even under the most optimistic scenario, 98% of 

reefs will be stressed by 2050 (Id.). In the Pacific subtropical ocean near Hawaii, there are nearly 

20 years of time-series measurements of significant decreasing seawater pH that match the 

ocean’s uptake of atmospheric CO2 (Dore et al. 2009) 

4. Atlantic Coast 

Even ocean waters not at high latitude, in upwelling systems, or containing coral reefs 

ecosystems are, or will soon be, exhibiting signs of ocean acidification. Observations of East 

Coast waters during all seasons show that while they remain supersaturated with respect to 

aragonite, by the end of this century, saturation states of aragonite and calcite will decrease by 

20–40%, with the lowest Ωar dropping to 1.3 in some seasons (Jiang et al. 2010). A survey of the 

Atlantic Coast showed that waters in the Northeast and particularly the Gulf of Maine are the 

most susceptible to ocean acidification (Wang 2013). 

iii. CO2 Kills and Injures Marine Life 

High-CO2 waters seriously harm marine wildlife and the entire ocean ecosystem. When CO2

concentrations in seawater increase, the availability of carbonate ions decreases, making it more 

difficult for marine organisms to form, build, and maintain the calcium carbonate shells and 

skeletons required for their survival. As seawater becomes more corrosive, it can kill fish eggs 

and inhibit the development of, and essentially dissolve, the shells of small crustaceans, baby 

shellfish, and other tiny creatures at the base of the food web (Fabry 2008). Ocean acidification 

also harms and stresses fish, squid, and other animals that do not build shells (Id.). Not only does 

ocean acidification directly threaten various types of marine animals, it also has implications for 

the broader marine environment and food web. 

The harmful effects of ocean acidification have already begun to occur. For example, ocean 

acidification has caused: 

 A massive die-off of oysters in the Pacific Northwest (Barton et al. 2012; R. a. Feely, 

Sabine, et al. 2012; Washington State Blue Ribbon Panel 2012); 
13 

 Declines in abundance and size of the California mussel, blue mussel and goose barnacle 

in tidepools correlated with a severely declining pH (Wootton et al. 2008); 

 Sluggish growth of corals in the Caribbean and Great Barrier Reef (De’ath et al. 2009; 

De’ath et al. 2012; Gledhill et al. 2008); and 

 Shells of plankton to dissolve off the California Coast and thinner and weaker shells of 

plankton in the Southern Ocean (Bednarsek 2014; Moy et al. 2009). 

In a meta-analysis of over 400 experiments examining the impacts of ocean acidification on 

marine organisms, Kroeker et al. (2013) found the biological effects to be generally large and 

negative. This analysis was restricted to experiments with pH manipulations of less than 0.5 

units, in order to reflect the predicted level of ocean acidification by the end of the century (IPCC 

2007). By limiting the analysis to small variations in pH, this study shows that within the 

foreseeable future ocean acidification will have “profound repercussions for marine organisms” 

(Kroeker et al. 2010). While the negative effect of ocean acidification was most pronounced for 

calcification and survival (27% reductions in both responses), the study also revealed significant 

negative effects on growth and reproduction (11 to 19%, respectively). In addition, abundance 

was reduced by 15%. The strength of this analysis suggests that the patterns highlighted in this 

study are a robust representation of the current literature on ocean acidification. 

While most of the worst consequences of ocean acidification are predicted for the future, 

scientists have already observed damage from CO2 in the oceans. Additionally, the impacts of 

ocean acidification can affect the entire marine food web by altering habitat, prey availability, 

and species interactions. 

b. High-CO2 Waters Injure the Growth, Survival, Fitness, and 

Reproduction of Marine Animals 

The primary known harm of CO2 in the oceans is that it impairs the growth and survival of 

animals that build shells. Because ocean acidification reduces the availability of carbonate ions 

that marine animals use to calcify their shells and skeletons, CO2 reduces the ability of these 

animals to build their protective structures (Doney et al. 2009). Acidified waters can also damage 

and dissolve shells. 

These negative effects have been observed in the ocean as well as documented in laboratory 

studies. Corals, coralline algae, plankton, mollusks, and other shellfish exposed to future levels 

of ocean acidification have all experienced problems (Kleypas & Yates 2009; Kuffner et al. 

2007; Barton et al. 2012; Talmage & Gobler 2011; Talmage & Gobler 2009; Orr et al. 2005; 

Riebesell et al. 2000). 

i. Molluscs, Echinoderms, and Crustaceans 

High CO2 waters are lethal to shellfish. Since 2005, waters off the coast of Washington and 

Oregon have been killing oysters and other molluscs. Shellfish hatcheries in Washington and 

Oregon reported massive mortalities of oyster larvae (Washington State Blue Ribbon Panel 

2012).Wild oysters also failed to reproduce in Willapa Bay, Washington (Id.). Scientists have 

definitively linked oyster production failures to high-CO2 ocean waters that were used to raise 

larvae (Barton et al. 2012). 
14 

In response to reported shellfish hatchery problems in Oregon, Barton et al. reported the results 

of their observations from the Whiskey Creek Hatchery on Netarts Bay in the summer of 2009 

(Barton et al. 2012). Unlike previous laboratory experiments, this study analyzed calcifying 

organism responses in the ambient-water CO2 chemistry of Oregon’s coastal waters. Larval 

production and mid-stage growth (~120 um to ~150 um) of the oyster, Crassostrea gigas, were 

both significantly negatively correlated with the chemistry of waters in which larval oysters were 

spawned and reared for the first 48 hours of life. Although the impact of the exposure was not 

immediate, the delayed reaction caused a significant decline in growth for mid-sized oyster 

larvae and reduced overall production. The findings corroborate other laboratory studies that 

show that many marine species, especially at the larval stage, are adversely affected by ocean 

acidification. 

Scientific studies have demonstrated that even modest pH declines affect the sensitive and 

vulnerable early developmental stages of organisms because these life histories have specific 

environmental needs (Kurihara 2008) (see Figure 10, below, showing negative effects from low 

pH treatments). A number of studies have found a delay in development or less development, 

degraded shells, decreased rate of metamorphosis, shell thickness, and loss of hinge integrity 

(Ross et al. 2011a). The resulting reduced larval size can reduce the feeding efficiency of larvae, 

and smaller larvae are more susceptible to starvation because they encounter comparatively less 

food (Kurihara & Shirayama 2004). Sub-lethal effects of elevated acidity can severely alter the 

composition and fitness of larvae, and given the high mortality rates of larvae in the water 

column and during the transition to benthic settler, small perturbations to larvae potentially may 

have large alterations to settlement dynamics, post-settlement mortality, recruitment, and 

ultimately adult populations (Ross et al. 2011). 

Watson et al. (2009) exposed one day-old oyster larvae to a range of pH conditions, from 7.6 to 

8.1, for 10 days and showed significant decline in the survival and growth of young larvae at 

lower pH. Waldbusser et al. (2010), in a study on the Chesapeake Bay, showed that even modest 

changes in pH present conditions that are corrosive to shells and have physiological impacts on 

adult and larval oysters. Biocalcification declined significantly with a reduction of 0.2 pH units, 

making juvenile bivalves more susceptible to predation and other mortality factors (Id.). 

Negative effects have been seen on the metamorphosis, size, and survival of larval hard clams 

(Mercenaria mercenaria), bay scallops (Argopecten irradians), and Eastern oysters (Crassostrea 

virginica) at levels of CO2 predicted to occur in the 21st century (Talmage & Gobler 2011). At 

650 ppm, or an approximate drop of 0.3-0.4 from pre-industrial values, both M. mercenaria and 

A. irrandians larvae exhibited dramatic declines (over 50%) in survivorship as well as 

significantly delayed matamorphosis and significantly smaller size. C. virginica also experienced 

lowered growth and delayed metamorphosis at this level, an indicator that current and future 

increases in CO2 populations may deplete or alter the composition of shellfish populations in 

coastal ecosystems (Id.). 

The Olympia oyster, Ostrea lurida, a foundation species in estuaries along the Pacific coast, 

exhibits clear decline in larval growth and settlement as levels of CO2 affect seawater pH. 

(Hettinger et al. 2012). Oysters in this experiment were raised at three levels of seawater pH, 
15 

including a control (8.0) and two additional levels (7.9 and 7.8). Larvae reared under pH 7.8 

exhibited a 15% decrease in larval shell growth rate, and a 7% decrease in shell area at 

settlement, compared to larvae reared under control conditions. Impacts were even more 

pronounced a week after settlement, with juveniles that had been reared as larvae under reduced 

pH exhibiting a 41% decrease in shell growth rate. 

Oysters on the Atlantic coast also experience the ill effects of ocean acidification. Dickinson et 

al. (2012) found negative effects on juvenile eastern oysters after exposure to water with a 0.2 

pH change. Exposure of the oysters to elevated acidity led to a significant increase in mortality, 

reduction of tissue energy stores and negative soft tissue growth, indicating energy deficiency. 

Under ocean acidification conditions, thermal tolerance is impaired in oyster larvae, leading to 

reduced development, size and increased abnormality (Ross et al. 2011; Parker et al. 2010). 

Similar results have been found in red abalone, with thermal tolerance impaired at pH 7.87 

compared to control (pH 8.05) (Zippay and Hoffman 2010). 

In studies with edible mussel (Mytilus edulis) and Pacific oyster (Crassostrea gigas) researchers 

found a strong decline of calcification under ocean acidification conditions (Gazeau et al. 2007). 

Based upon these results, researchers concluded that mussel and oyster calcification may 

decrease by 25% and 10%, respectively, by the end of the century.” (Id.). Oysters and mussels 

also exhibit development abnormalities when exposed to acidification (Kurihara 2008). When 

oyster eggs were reared under pH 7.8, they showed malformations of their shell, and when reared 

under pH 7.4, more than 70% of the larvae were either completely non-shelled, or only partially 

shelled, and only 4% of CO2 treated embryos developed into normal larvae by 48 hours after 

fertilization, in contrast to about 70% successful development in control embryos. 

The shrimp Palaemon pacificus displayed variable responses at different developmental stages, 

pH and length of exposure (Kurihara 2008). Following long term (30 weeks) exposure of adults 

to pH 7.89 and 7.64, survival and egg production in early developmental stages decreased in both 

treatments. Findlay et al. (2010) found a slower rate of development of embryos in the common 

intertidal northern hemisphere barnacle Semibalanus balanoides with an estimated 19 days delay 

in reaching 50% hatching stage at pH 7.7. Other amphipods have exhibited metabolic changes in 

response to acidification levels greater than what is allowed under the federal criterion (Hauton 

et al. 2009). 

Echinoderms exhibit delayed and asymmetrical development when exposed to acidified 

conditions. In the absence of adequate adaptation or acclimation, lowered pH levels will have a 

range of sub-lethal effects on sea urchins, brittlestar and seastar larvae from a range of 

geographical regions (Ross et al. 2011). Larvae of the ecological keystone brittlestar, Ophiothrix 

fragilis, either were abnormal, had altered skeletal proportions, or asymmetry during 

skeletogenesis, and there was a delay in development at pH levels of 7.9, or approximately 0.3 

units below current surface levels (Gutowska et al. 2009). Other experiments on brittlestar in low 

pH waters resulted in dramatic results; acidification of 0.2 units induced 100% larval mortality 

within an eight day period. Control larvae showed 70% survival over the same period. Because 

the calcite skeleton of the larval brittlestar aids key functions such as feeding and vertical 

migration, and defense against predators, abnormal development of the skeleton will have drastic 

consequences for fitness. The developmental abnormalities may be exacerbated by temperature 
16 

increases predicted for the end of the century; some scientists suggest that this may result in the 

disappearance of echinoderms from the surface oceans within the next 50-100 years (Ross et al. 

2011a). 

Reproductive success is compromised by ocean acidification. The fertilization rate of sea urchins 

decreases with increasing CO2 concentrations (8.1 to 6.8 pH) (Kurihara 2008). In another sea 

urchin experiment utilizing six CO2 concentrations, with a pH between 8.01 (control) and 6.83, 

cleavage rate, developmental speed, and larval morphology all declined with increased CO2

concentration (Kurihara & Shirayama 2004). At a 0.2 change from control, effects could be seen 

on the morphology and development of the larvae, and these effects became more pronounced 

with greater pH changes (Id.) (see Figure 4, below). The authors concluded that “all the effects 

of raised CO2 concentration observed in this study would have a negative impact on the survival 

of sea urchin embryos in their early life history.” A recent study showed that sea urchin sperm 

flagellar motility was significantly reduced when seawater pH decreased by .3 units, from 8.0 to 

7.7 (Suwa et al. 2010). As discussed above, decreased flagellar motility has severe consequences 

for fertilization and subsequent population dynamics; if sperm lose their ability to find eggs, the 

population size will necessarily diminish. 

Figure 4. Declining development of sea urchin larvae exposed to acidified waters (Kurihara & Shirayama 2004).

Even moderate increases in atmospheric CO2 and ensuing acidification adversely affect the 

growth of both gastropods and sea urchins (Shirayama & Thornton 2005). Before the end of this 

century, atmospheric CO2 is likely to increase by more than 200 ppm, decreasing the pH of the 

ocean by approximately 0.3 units from pre-industrial levels. Two species of sea urchin as well as 

the gastropod Strombus luhanus were exposed for six months to waters with this level of 

elevated CO2, and all three species exhibited similar consequences. Increased CO2 negatively 

affected growth rate, calcification, shell height and body mass, and metabolic activity 
17 

(Shirayama & Thornton 2005). The developing embryos of the gastropod and intertidal snail 

Littorina obtusata also demonstrate slower overall development time, altered embryonic 

movement, and modification of shell shape in hatchlings while exposed to acidified waters (pH 

7.6) (Ellis et al. 2009). 

Arnold et al. (2009) investigated the effect of ocean acidification on lobsters and found that 

indirect disruption of calcification and carapace mass may adversely affect the competitive 

fitness and recruitment success of larval lobsters with serious consequences for population 

dynamics and marine ecosystem function 

Reduced metabolism is expected to impair predator-prey interactions, as well as have 

consequences for growth, reproduction, and survival. Metabolic suppression has previously been 

reported to occur in a variety of adult marine invertebrates, including crabs, squid, worms, 

bivalves, pteropods and amphipods (Albright 2011). Slowed metabolism is generally achieved 

by halting energy-expensive processes, such as protein synthesis, and therefore may lead to 

reductions in growth and reproductive potential (Id.). The blue mussel Mytilus edulis has strong 

physiological mechanisms by which it is able to protect body tissues against short-term exposure 

to acidified seawater, but these come at an energetic cost, and will result in reduced growth 

during long term exposures (Bibby et al. 2008). Consequently, the predicted long-term changes 

to sea water are likely to have a significant effect on the health and survival of blue mussel 

populations (Id.). Mussel beds are a dominant coastal habitat and provide food and structure for a 

diverse array of species in an otherwise physically stressful environment; any decline in their 

population structure will lead to a reduction in appropriate habitat for a myriad of other species. 

In summary, acidified waters impact the development, growth, and reproductive success of a 

suite of echinoderms, crustaceans, and molluscs. A growing body of information is becoming 

available on the effecting of declining pH on these organisms and their ecosystems. The results 

of these studies are clear; as pH falls even 0.2 units from pre-industrial values, these organisms 

will struggle to survive in their increasingly acidic environment. 

ii. Corals 

Coral reef ecosystems, which are estimated to harbor one-third of marine species and which 

support the livelihoods of a half billion people, are particularly threatened by ocean acidification. 

Some corals are already experiencing reduced calcification (De’ath et al. 2009; Cooper et al. 

2008; Bates et al. 2010; Gledhill et al. 2008). Due to the ocean acidification and warming, reefs 

are projected to experience “rapid and terminal” declines worldwide at atmospheric CO2

concentrations of 450 ppm (Veron et al. 2009; Bijma et al. 2013). Prominent coral scientists have 

called for reducing atmospheric CO2 to less than 350 ppm to protect coral reefs from collapse 

(Veron et al. 2009, Frieler et al. 2012). Coral reefs cannot exist below 7.8 pH units (Fabricius et 

al. 2011), and the threshold for coral growth is 3.3 Ωar (Meissner et al. 2012). 

Ricke et al. (2013) analyzed aragonite saturation state (Ωar) surrounding reefs in CMIP5 

simulations under several representative concentration pathway (RCP) scenarios (Ricke et al. 

2013). The study found that in preindustrial times, 99.9% of reefs adjacent to open ocean in the 

CMIP5 ensemble were located in regions with Ωa > 3.5. Accordingly, the study used Ωa = 3.5 as 
18 

an upper bound viability threshold for corals, while also examining thresholds of Ωa = 3.25 and 

3. Under a business-as-usual scenario (RCP 8.5), every coral reef considered was projected to be 

surrounded by water with Ωar < 3 by the end of the 21st century and the reefs’ long-term fate was 

independent of their specific saturation threshold. Under scenarios with significant CO2

emissions abatement, the Ωar threshold for reefs was critical to projecting their fate. The study 

concluded that the “results indicate that to maintain a majority of reefs surrounded by waters 

with Ωar > 3:5 to the end of the century, very aggressive reductions in emissions are required.” 

Corals are among the ecosystems most threatened by ocean acidification. To date, most scientific 

investigations into the effects of ocean acidification on coral reefs have been related to the reefs’ 

unique ability to produce voluminous amounts of calcium carbonate (Kleypas & Yates 2009). 

The persistence of carbonate structures on coral reefs is essential in providing habitats for a large 

number of species and maintaining the extraordinary biodiversity associated with these 

ecosystems. As a consequence of ocean acidification, the ability of marine calcifiers to produce 

calcium carbonate will decrease, resulting in a transition from a condition of net accretion to one 

of net erosion, with drastic consequences for the role and function of these ecosystems (Kleypas 

& Yates 2009). 

Coral reefs are predicted to drastically lower their calcification rates in the near future, and 

historical records show that calcification rates have already fallen relative to pre-industrial 

values. According to scientists, the main reef building organisms will calcify up to 50% less 

relative to pre-industrial rates by the middle of this century (Id.). A drop of approximately 60% 

coral reef calcification is projected for the end of the century, when pH is predicted to fall 0.5 

units below pre-industrial values (Caldeira & Archer 2007). Many studies suggest calcification 

rates could be reduced between 20-60% at 560ppm, or 7.9 pH, and that a reduction of this 

magnitude would fundamentally alter reef structure and function (Convention on Biological 

Diversity 2009). According to the model of Silverman et al. (2009), developed from field 

observations from more than 9,000 reef locations, all coral reefs are expected to reduce 

calcification by more than 80% relative to their pre-industrial rate at 560 ppm (0.3 pH change), 

and at this point “all coral reefs will cease to grow and start to dissolve.” The Interacademy Panel 

on International Issues concurs; “at current emission rates models suggest that all coral reefs and 

polar ecosystems will be severely affected by 2050 or potentially even earlier.” 

In a meta-analysis on coral calcification responses to ocean acidification, the coral calcification 

declined by a mean of 15% per unit decrease in aragonite saturation state (2 < Ω < 4) (Chan and 

Connolly 2013). On current emission trends, calcification will decline 22% on average for corals 

by the end of the century (Id.). This falls to the lower range of responses that have been predicted 

by ocean acidification researchers and described above, which the authors believe reflects 

variation in the calcification responses of different corals. 

Calcification rates at coral reef locations in the western tropical Pacific and the Caribbean may 

have already declined by 15%, (Caldeira & Archer 2007), and data from the Great Barrier Reef 

indicates a 14% decline in calcification rates between 1990 and 2005 (De’ath et al. 2009). Other 

studies in the Great Barrier reef indicate a decline of approximately 21%, and analysis of coral 

growth records confirm that this decline is unprecedented in recent centuries (Cooper et al. 

2008). A model based on field samples shows that calcification of coral reefs in French 
19 

Polynesia declined 15% between the pre-industrial period and 1992, and that rates will decline 

40% by 2050, when CO2 levels reach 560 ppm (pH 7.9) (Anthony et al. 2011). Near Bermuda, 

historical records show that coral skeletal density has decreased 33%, and coral calcification 

rates have declined by 52% as a result of changes in seawater carbonate chemistry (Bates et al. 

2010). These observed changes have occurred even before a 0.2 unit decline in ocean pH; as 

atmospheric CO2 continues to rise and lower pH values, calcification rates will maintain their 

precipitous decline. 

Ocean acidification acts in concert with ocean warming and coral bleaching in furthering coral 

reef decline (Anlauf et al. 2011) (observing a 3% reduction in acidification with a 0.2 decline in 

pH, and a 30% decline when acidification is coupled with 1° C warming). While natural 

variability in the annual cycle and interannual variability may account for some of the observed 

change in coral growth rates, scientists are “virtually certain” that anthropogenic trends already 

exceed natural variability (Friedrich et al. 2012). Studies projecting the combined impacts of 

ocean acidification and ocean warming on corals predict that coral erosion will exceed 

calcification rates at atmospheric CO2 concentrations of 450 to 500 ppm, (Hoegh-Guldberg et al. 

2007), and all coral reefs will begin dissolve at CO2 concentrations of 560 ppm (Silverman et al. 

2009). These figures correspond to a 0.2 and 0.3 unit drop in pH, respectively, as compared to 

pre-industrial values. Van Hooidonk et al. (2014) presented updated global projections for threats 

to coral reefs from ocean warming and ocean acidification based on ensembles of IPCC AR5 

climate models using the Representative Concentration Pathways (RCPs). For all tropical reef 

locations, the study projected absolute and percentage changes in aragonite saturation state (Ωar) 

for the period between 2006 and the onset of annual severe bleaching. 

 In the Caribbean, a recent study concluded that “coral reef communities are likely to be 

essentially gone from substantial parts of the Southeast Caribbean by the year 2035” 

(Buddemeier et al. 2011). The Great Barrier Reef has lost 50% of its coral cover since 1985 as a 

result of the combined effects of ocean acidification, global warming, coral bleaching, coral 

predation by starfish, and cyclone damage (De’ath et al. 2012). In short, due to the synergistic 

impacts of ocean acidification, mass bleaching, and local impacts, coral reefs are projected to 

experience “rapid and terminal” declines worldwide at atmospheric CO2 concentrations 450 

ppm, or pH 8.0, a level that is expected before mid-century (Veron et al. 2009). 

Many experimental studies show declining calcification rates and other ill effects when corals 

are exposed to acidified waters. Decreases in calcification rates across a suite of benthic species 

and calcifying systems range from 3 to 60% for a doubling in pCO2, which corresponds to a 0.3 

reduction in pH (Abbasi & Abbasi 2011). The average response of corals is a 30% decline in 

calcification in response to a doubling in pCO2 (Id.). In a study of an assemblage of corals 

exposed to conditions designed to mimic the change that may be experienced in the next 50-100 

years (pH decline of 0.22 to 0.28 units), calcification rates declined between 44% and 80%. 

The coral Acropora palmata (listed as threatened under the Endangered Species Act), once the 

dominant reef building coral in the Caribbean, experiences impaired fertilization, settlement, and 

growth with increasing pCO2 (Albright et al. 2010). The cumulative impact of ocean 

acidification on fertilization and settlement success is an estimated 52% and 73% reduction in 

the number of larval settlers on the reef under pCO2 conditions projected for the middle and end 
20 

of this century, respectively (0.2 and 0.5 decline in pH) (Id.). After only 8 days of high CO2

conditions (pH 7.75), Acropora experiences a statistically significant (18%) reduction in 

calcification rate (Murubini et al. 2003). Furthermore, there 22 coral species listed as threatened 

under the Endangered Species Act primarily because of threats from ocean warming, 

acidification and disease. The rule proposing listing for the corals found that ocean acidification 

was one of the highest priority threats for corals: 

Ocean acidification has the potential to cause substantial reduction in coral 

calcification and reef cementation. Further, ocean acidification adversely affects 

adult growth rates and fecundity, fertilization, pelagic planula settlement, polyp 

development, and juvenile growth. 

77 Fed. Reg. at 73230 (Dec. 7, 2012). In other words, ocean acidification is driving the 

extinction of corals and the destruction of coral reef ecosystems. 

Experimental studies evaluating the effects of ocean acidification on early life history stages of 

corals generally conclude that primary polyp growth is hindered by increasing acidity (Albright 

et al. 2010, Cohen & Holcomb 2009). Renegar and Riegl (2005) showed a significant decrease in 

the growth rate of Acropora cervicornis larvae at pH levels 0.3-0.5 units below control. Larvae 

of the common Atlantic golf ball coral, Favia fragum, shows significant delays in both the 

initiation of calcification and subsequent growth of the primary corallite in acidic waters (8.17 – 

7.54 pH) (Cohen & Holcomb 2009). Visible changes in the skeletal development were observed 

in all non-control treatments, and in the most acidic waters skeletal development was 75% less 

than the control. 

Acidification also affects cold water corals. Cold water corals have a worldwide but patchy 

distribution, and are often found in areas with highly productive fisheries (De Mol et al. 2002; 

Kenyon et al. 2003). Overall, more than two-thirds of all known coral species are cold water 

corals (Roberts & Hirshfield 2012; Cairns 2007). Recent exploration and research that has begun 

to search for, map, and observe cold water corals has found that these organisms are fragile, 

long-lived, slow-growing, very sensitive to physical or environmental disturbance and adapted 

for a specific environmental niche (McDonough & Puglise 2003). Alaskan waters are already 

showing widespread evidence of ocean acidification as a result of greenhouse gas emissions 

(Mathis et al. 2011a). By 2100, 70% of cold-water corals will be exposed to corrosive waters 

(Convention on Biological Diversity 2009). Conditions in waters typically inhabited by coldwater corals are even less favorable for calcification than those experienced by warm water 

corals; this may cause cold-water corals to be affected earlier and more strongly by CO2-related 

ocean acidification than their warm water counterparts (Abbasi & Abbasi 2011). 

The vulnerable early developmental and reproductive stages of cold water corals may be 

especially strongly impacted (Kurihara 2008; Dupont & Thorndyke 2009; Kroeker et al. 2010). 

In an experiment on the cold-water coral Lophelia pertusa, lowering the pH by 0.3 units relative 

to the ambient level resulted in calcification being reduced by 56% (Maier et al. 2009). Lower 

pH reduced calcification more in fast growing, young polyps (59% reduction) than in older 

polyps (40% reduction). Thus, corals’ larvae and young corals are significantly more susceptible 

to ocean acidification than adults, and will likely show a higher degree of reduced calcification 
21 

and growth with reduced pH, making young and larval corals less likely to survive to maturity as 

the ocean continues to absorb anthropogenic CO2 and as climate change progresses. 

In addition to reduced calcification rates, the strength of cementation may also be reduced in 

waters with a lower pH, promoting higher rates of physical and bio-erosion (Manzello et al. 

2008). Once coral reefs experience lowered calcification and poor cementation, erosion and reef 

flattening can result, which severely reduced the structural heterogeneity of reefs and lowers its 

potential to support biodiversity. An important new study of reef bioerosion determined that the 

combined effects of lower calcification with increased bioerosion can significantly degrade coral 

reefs (Wissshak et al. 2012). In the study, a common bioeroding sponge in the Great Barrier Reef 

was observed on massive Porites. The sponge was more effective at bioerosion of the corals at 

high CO2, ranging from 17% increase from present day levels to 61% increase at the highest 

CO2 treatment. The researchers describe the important role of balancing the antagonistic 

processes of calcification and bioerosion in a reef for a healthy coral ecosystem, and predict 

detrimental consequences under ocean acidification as calcification declines and bioerosion 

increases. 

Bioerosion may result in a loss of change in fish assemblages, lower densities of commercially 

important species, and lower rates of larval fish recruitment (Feary et al. 2007). Weaker reef 

calcification and cementation also increases the potential for reef damage as storm frequency and 

intensity increases with continued global warning, leading to further reef degradation (Id.). In a 

study looking at the impacts of storm damage and ocean acidification, researchers concluded that 

table coral populations are vulnerable to collapse (Madin et al. 2012). In the Indo-Pacific, table 

corals provide an important role in the reef ecosystem by creating reef structure and sheltering 

other reef species. They are also particularly vulnerable to ocean acidification, thermal stress, 

bleaching, disease and stress from storm waves. The table corals will become more vulnerable to 

storm waves as ocean acidification reduces calcification and increases bioerosion, therefore 

weakening their cementation and structure. Madin et al. (2012) found that a coral colony was 

four times more likely to be dislodged by a storm wave by the end of the century ocean 

acidification levels. Because of this vulnerability, the results showed that table corals are prone 

to large and rapid declines in coral cover. 

Numerous biological responses independent of calcification are also negatively impacted by 

ocean acidification. Corals in acidifying waters are likely to be in a nutritionally or energetically 

stressed state and thus less likely to initiate reproduction, or successfully reproduce, due to 

negative impacts of ocean acidification on all stages of the reproductive cycle (Maier et al. 2009; 

McCulloch et al. 2012). Sperm flagellar motility also declines in response to decreasing pH. If 

sperm lose their ability to find eggs in the vast extent of the sea, the life of marine organisms is 

potentially limited. Sperm flagellar motility, which is indispensable for fertilization, is regulated 

by an elevation of intracellular sperm pH (Morita et al. 2010). While 69% of Acropora sperm 

were motile at pH 8.0, 46% were motile at pH 7.8, and fewer than 20% at pH 7.7 (Id.). 

Additionally, the physiological costs associated with reproduction are more likely to result in the 

demise of the organism due to the compounding stressors from ocean acidification and climate 

change (Wood et al. 2008, Cohen & Holcomb 2009). Significant reductions in metabolism have 

been observed for coral larvae following exposure to waters with a 0.2 decline in pH, levels 

projected to occur by the middle of this century (Albright & Langdon 2011). 
22 

Albright et al. (2010) concluded that with increased CO2 concentrations to those projected to 

occur in this century (560 atm to 800 atm, or a 0.3 to 0.5 decline in pH from pre-industrial 

values), the fertilization success of the tropical reef-building coral Acropora palmata decreased 

by 12-13%, settlement success reduced 45-69%, and linear extension was significantly reduced. 

The compounding effect of these impacts translated to 52-73% reduction in the number of larval 

settlers on the reef. Albright et al. (2010) predicted that the net impact on recruitment would 

actually be greater than that given that the depressed post-settlement growth is likely to result in 

elevated rates of post-settlement mortality. This corroborates other studies showing negative 

impacts on early-stage tropical corals. 

Albright and Langdon (2011) tested the effects of ocean acidification on sexual recruitment of 

tropical corals. Larval metabolism was depressed by 27% at acidification levels expected by 

mid-century (0.3 pH reduction) and 63% at end-of-century acidification levels (0.4-0.5 pH 

reduction). Settlement was also reduced 42-45% and 55-60% at the mid and end-of-century 

levels respectively, relative to controls (Albright & Langdon 2011). Another study of larvae of 

tropical corals showed that short-term or long term exposure of larvae to ocean acidification 

decreased their metamorphosis (Suwa et al. 2010). This means that even when larval 

survivorship is unchanged, the success of recruiting new corals could be inhibited by ocean 

acidification (Id.). 

Additionally, under conditions of acidification planktonic larvae lose their preference for 

settlement on the optimal crustose coralline algae communities (Doropoulos et al. 2012). 

Crustose coralline algae in turn, will experience a lower recruitment rate as marine waters 

become more acidic. Crustose coralline algae, a red calcifying algae, is of key importance in 

coral reef ecosystems, stabilizing reef structures and providing an important food source for 

benthic organisms (Convention on Biological Diversity 2009). Crustose coralline algae form a 

major calcifying component of the marine benthos from polar to tropical regions and are 

considered to influence the settlement of coral recruits. With a mean pH change of 0.26 between 

control and treatment, Kuffner et al. (2007) found that crustose coralline algae growth rates 

declined by 40%, and recruitment rate and percentage cover decreased by 78% and 92%, 

respectively. 

In sum, reproduction is critical to maintaining a healthy coral reef population, and the long-term 

impacts of ocean acidification on reproduction, especially on larval settlement and growth, may 

significantly reduce the corals’ ability to recover or maintain a population in the face of human 

caused disturbances and anthropogenic CO2 emissions. This would result in a lack of 

reproductive capacity, genetic bottlenecks, and population collapse (Dupont et al. 2010; Ross et 

al. 2011). 

As the world’s oceans become more acidic and less saturated with carbonate minerals, corals are 

expected to build weaker skeletons and experience slower growth rates, which will make it more 

difficult for corals to retain competitive advantage over other marine organisms (Guinotte et al. 

2006). As coral skeletons weaken, they will become increasingly at risk of storm damage and 

bioerosion, which will reduce the structural complexity of the reef system, reducing habitat 

quality and diversity alongside the loss of coastal protection functions (Hoegh-Guldberg et al. 

2007). At greater than 550 ppm, coral reef ecosystems will be reduced to “crumbling 
23 

frameworks.” (Id.). Extensive studies have demonstrated that small changes in ocean chemistry 

will cause a suite of negative impacts, from reduced calcification rates to lowered reproductive 

success. 

iii. Plankton 

Plankton, which comprise the basis of the marine food web, are among the calcifying organisms 

adversely affected by ocean acidification. Changes to calcifying zooplankton, such as pteropods 

and foraminfera, have the potential to affect the ecological and tropic dynamics which govern the 

exchange of energy and cycling of nutrients throughout the marine food web (Gattuso & 

Hansson 2011). For example, the shelled pteropod, Limacina helicina, an Arctic pelagic mollusc, 

is a food source for higher predators such as fishes, whales and birds that are particularly 

important in high latitude areas. L. helicina makes up about 60 percent of the pink salmon diet 

(Comeau et al. 2012). A decline of pteropod population would likely cause dramatic changes to 

various pelagic ecosystems, and impact the commercially important salmon fishery; a 10% 

decrease in pteropods can lead to a 20% reduction in pink salmon body weight (Aydin 2005). 

Pteropods form integral components of food webs, and are considered an overall indicator of 

ecosystem health (Orr et al. 2005). Studies have shown that pteropods exposed to a pH value 

predicted for the end of this century exhibited a 28% decrease in calcification (Comeau et al. 

2009). Experiments on L. helicina showed that changes from 8.05 pH to 7.89 pH (Δ -0.16 units) 

cased shell dissolution and cracks appeared at 7.76pH, and linear extension of the shell decreased 

as a function of declining pH (Comeau et al. 2012). Samples show dissolution already happening 

in areas that have low aragonite saturation states. A sampling study off the coasts of California, 

Oregon, and Washington showed average to severe dissolution of L. helicina for 53% of onshore 

individuals and 24% of offshore individuals (Bednarsek 2014). A sampling study in 2008 of the 

Southern Ocean found severe dissolution of L. helicina in Ωara 1.0 (Bednarsek 2012). Another 

study found shell weights of one form of Antarctic species declined 35% from 1997-2006 

(Roberts unpublished). 

Ample studies corroborate that high CO2 waters dissolve the shells of L. helicina and reduce 

calcification rates. Comeau et al. (2010) noted decreased calcification for L. helicina with 

decrease in aragonite saturation. Lishka (2012) looked at overwintering L. helicina and L. 

retroversa in the Arctic and noted that they do not calcify in the winter, and they are subject to 

dissolution under high CO2 conditions. Bednarsek (2012) looked at L. helicina and Clio 

pyramidata from the Southern Ocean under different aragonite saturation states and recorded 

dissolution stages. 

Modeling by Comeau et al. (2012) shows that by the end of the century Limacina helicina will 

not be able to calcify over much of the Arctic because of aragonite undersaturation—prediction 

may be conservative because it did not account for shell dissolution. Commentary suggests that 

as waters warm these pteropods will be trapped in acidified conditions and will “disappear 

entirely by the end of the century.” Modeling suggests that waters in the California Current will 

be undersaturated year-round by 2050 (Gruber 2012). Modeling of the Arctic suggests that by 

mid-century the Bering Sea will be persistently undersaturated with respect to aragonite (Mathis 

2011). An analysis of survey measurements in 2005-2006 and 1991-1992 demonstrated a 
24 

shoaling of the aragonite saturation state in waters off Alaska (Feely et al. 2012). In the North 

Pacific the aragonite saturation state shoaled to depths less than 200 m between 40 ̊N and 50 ̊N 

(Id.). On average, the calcite saturation horizon in the Pacific shoaled about 1 m/yr from 1991 to 

2006 (Id.). 

Other species of plankton are also harmed by CO2. Another pteropod, Clio pyramidata, kept in 

aragonite undersaturated waters began to dissolve within two days (Orr et al. 2005). Some 

coccolithophorids are also susceptible to ocean acidification. Studies showed that CO2 related 

changes to seawater caused reduced calcification, resulting in malformed and incomplete shells. 

Calcification of cocolithophorids declined 15-44%, and their shells were malformed as pH 

changed up to about 0.3 units (Riebesell et al. 2000). Coccolithophorids are globally distributed 

and bloom in massive areas affecting the optical properties of the ocean, reflecting light from the 

earth, and play a major role in the ocean carbon cycle. Elevated CO2 concentrations also reduce 

the shell mass of foraminifera (Kleypas et al. 2006). Modern shell weights of foraminifera in the 

Southern Ocean are 30–35% lower than those from preindustrial sediments, which is consistent 

with reduced calcification induced by ocean acidification (Moy et al. 2009). 

iv. Cephlopods and Fish 

The negative physiological effects of ocean acidification are not confined to invertebrates. For 

example, the gametes, embryos, and larvae of vertebrates such as fish are vulnerable to changes 

in ocean chemistry and have shown impairments in their homing and predator/prey detection 

capabilities. 

Changes in the ocean’s CO2 concentration result in accumulation of CO2 in the tissues and fluids 

of fish and other marine animals, called hypercapnia, and increased acidity in the body fluids, 

called acidosis. These impacts can cause a variety of problems for marine animals, including 

difficulties with acid-base regulation, calcification, growth, respiration, energy turnover, 

predation response, and mode of metabolism (Pörtner et al. 2005; Pörtner et al. 2004). Studies 

have shown adverse impacts in squid and fish, among other animals (Rosa & Seibel 2008; 

Ishimatsu et al. 2004; Pörtner et al. 2004). For example, when exposed to acidification, orange 

clownfish suffer a type of brain malfunction that interferes with their homing abilities and makes 

them 5-9 times more likely to swim toward a predator (Munday et al. 2009; Simpson et al. 2011; 

Ferrari et al. 2011). 

Laboratory experiments have shown that ocean acidification at levels expected to occur within 

this century impairs larval orange clownfish and damselfish sensory abilities and behavior, 

making it more difficult for them to locate suitable settlement sites on reef habitat and avoid 

predators. Specifically, ocean acidification disrupts smell, hearing, and behavior of larval orange 

clownfish, (Munday et al. 2009; Nilsson et al. 2012), making larval clownfish attracted to odors 

from predators and unfavorable habitat (Munday et al. 2010; Dickson et al. 2010). Olfactory cues 

that prompted avoidance or neutral behavior in controls (pH 8.15) stimulated strong preference 

behavior in larvae raised at pH 7.8, in addition to significant reduction in response to usually 

positive preferences. Ocean acidification also impairs the hearing capacity of larval clownfish, 

which is predicted to have negative effects on settlement success and survival (Simpson et al. 

2011). 
25 

Similarly, research on six damselfish species found that ocean acidification impairs larval 

damselfish smell, vision, learning, behavior, and brain function, leading to higher risk of 

mortality. For example, in acidified waters, larval damselfish (1) become attracted to predator 

odors and display much riskier behaviors, making them more prone to predation; two species 

suffered a five-fold to nine-fold increase in predation rate at CO2 levels of 700 to 850 ppm, or 0.3 

pH units below control (Munday et al. 2009; Ferrari et al. 2011); (2) cannot discriminate between 

habitat olfactory cues, making it more difficult to locate appropriate settlement habitat (Devine et 

al. 2011); (3) settle on the reef during dangerous times—the full moon rather than new moon—

when they are more vulnerable to predation (Devine et al. 2011); (4) fail to visually recognize or 

evade important predator species; (5) cannot learn to respond appropriately to a common 

predator by watching other fish react or by smelling injured fish, unlike fish under normal 

conditions (Id.); and (6) suffer disruption of an important neurotransmitter which is thought to 

result in the sensory and behavioral impairment observed in acidified conditions (Nilsson et al. 

2012). 

An animal’s ability to transport oxygen is reduced by pH changes (Pörtner 2005). Water 

breathing animals have a limited capacity to compensate for changes in the acidity (Haugan 

2006). For example, fish that take up oxygen and respire CO2 through their gills are vulnerable 

because decreased pH can affect the respiratory gas exchange (Royal Society 2005). Changes in 

metabolic rate are caused by the changes in pH, carbonates, and CO2 in marine animals (Haugan 

2006). 

Squid, for example, show a very high sensitivity to pH because of their energy intensive manner 

of swimming (Royal Society 2005). Because of their energy demand, even under a moderate 

0.15 pH change squid have reduced capacity to carry oxygen and higher CO2 pressures are likely 

to be lethal (Pörtner 2004). Even species more tolerant to pH changes experience decreased 

metabolism from increased CO2 in the water (Pörtner 2004). For example, as much as 50% 

mortality was observed in copepods after only six days of exposure to waters with a pH level 0.2 

units below the control (Pörtner 2005). Reducing pH by 0.3 pH cased a 31% decline in metabolic 

rate and a 45% decrease in activity level for the jumbo squid, an important predator in the Easter 

Pacific (Rosa & Seibel 2008). 

In fish, pH also affects circulation. Fishexposed to high concentrations of CO2 in seawater 

experience cardiac failure and increased mortality (Ishimatsu 2004). At lower concentrations 

sublethal effects can be expected that can seriously compromise the fitness of fish. Juvenile and 

larval stages of fish were found to be even more vulnerable (Ishimatsu 2004). 

In sum, ocean acidification can have many adverse effects on marine animals that can reduce 

their fitness and survival (Royal Society 2005). Many marine animals have low thresholds for 

long-term CO2 exposure (Pörtner 2005). 

c. Other Environmental Impacts of Ocean Acidification 

i. Increased Toxicity of Harmful Algal Blooms and Sediments 

Ocean acidification may already be increasing the toxicity of harmful algal blooms known as 

“red tides.” These toxic red tides poison shellfish, marine mammals, fish, and even cause 
26 

paralytic shellfish poisoning in people. High CO2 levels in seawater magnify the toxins of 

harmful algae. (Fu et al. 2012; Avery O Tatters et al. 2013; Tatters et al. 2012; Avery O. Tatters 

et al. 2013). Studies of the genus Pseudo-nitzscia show that the toxicity of diatoms which 

produce a neurotoxin increases significantly under ocean acidification conditions. A -0.5pH 

change caused toxin production in the diatoms to increase 4.2-fold and a -0.3pH unit change 

increased the toxicity 2.5-fold (Tatters et al. 2012). Many studies on the effects of ocean 

acidification and algal blooms have been conducted at CO2 levels that are already occurring in 

California, and the increase in the toxicity of harmful algal blooms in Southern California (and 

resulting mass mortalities of fish and marine mammals) may be due, in part, to acidified waters 

(Id.) However, these studies suggest that the damage will become much worse. 

Additionally, research shows that under conditions of ocean acidification sediments become 

more toxic (Roberts, Birchenough et al. 2013). Ocean acidification makes sediment-bound 

metals more available and thus more toxic for aquatic life (Id.) For example, ocean acidification 

increases the toxicity of copper (Campbell & Mangan 2014). 

ii. Noise Pollution Increases in Low pH Waters 

Ocean acidification can also decrease the sound absorption of seawater, causing sounds to travel 

further with potential impacts on marine mammals and other marine life sensitive to the sounds 

of vessel traffic, seismic surveys, and other noise pollution (Hester et al. 2008). Sound travels 

10-15 percent further with a change of 0.1 pH, and it is predicted to increase about 40 percent by 

mid-century (Hester et al. 2008). Additionally, a decline of 0.3 pH units causes a 40 percent 

decrease in the sound absorption of surface seawater and sound may travel 70 percent farther, 

further affecting sensitive marine mammals (Brewer et al. 2009). 

d. Ocean Acidification’s Ecosystem Impacts 

While the full implications of elevated CO2 on marine ecosystems are not well-documented, 

there is high confidence that there will be negative ecosystem consequences from ocean 

acidification. The exact changes are difficult to predict, but some of the anticipated impacts 

include loss of diversity, loss of abundance of calcifying species, shifting prey and predator 

interactions, and loss of suitable habitat. 

New mesocosm studies have sought to understand some of the potential ecosystem impacts of 

CO2. Studies of biodiversity near underwater volcanic vents demonstrate reduced richness in 

high-CO2 waters. For example, coral species diversity declined by about 39% between low and 

high-CO2 sites, with the reefs shifting from complex communities to a coral reef dominated by 

massive Porites. Most importantly, the researchers found that coral reef development ceases at 

7.7 pH, and they concluded that a pH decline below 7.8 would be “catastrophic for coral reefs” 

(Fabricius et al. 2011). Scientists also observed that in high-CO2 waters the loss of complex coral 

reef habitat resulted in a loss of diversity of reef-associated species such as crustaceans and 

crinoids (Fabricius et al. 2014). Looking at the macroinvertebrates, the density declined 48% 

between control and high-CO2 areas and taxa diversity declined by 77% (Id.). 
27 

Loss of species diversity associated with ocean acidification can also result from changes in 

competitive interactions. A study of a rocky reef near volcanic vents documented that macro 

algae outcompeted calcareous species in low-pH waters (Kroeker et al. 2012). The researchers 

explained that under the high-CO2 conditions the calcifying species grew more slowly while the 

seaweed took hold and that grazing of seaweed was depressed (Id.). In another study, while the 

areas near volcanic vents lacked scleractinian corals and had low abundance of sea urchins and 

coralline algae, invasive algal species benefited from the acidified conditions (Hall-Spencer et al. 

2008). 

Research on the diversity the intertidal community in the Pacific Northwest documented a shift 

from a ecosystem dominated by calcifying animals to one with non-calcifying organisms as pH 

declined. Researchers documented declines in abundance and size of the California mussel, blue 

mussel, and goose barnacle in tidepools on the Olympic Coast in Washington (Wootton et al. 

2008). They found that in years with low pH waters the calcifying animals were replaced by noncalcifying organisms (Id.). 

The synergistic impacts of ocean acidification and warming are also potentially severe. Ocean 

acidification may induce a negative climate feedback that may increase temperature rise. 

Mesocosm studies found that ocean acidification may amplify global warming through 

decreasing biogenic production of the marine sulfur component dimethylsulphide which can 

impact cloud albedo (Six 2013). Ocean acidification therefore may also contribute to climate 

change impacts on the environment. 

2. Risk Reduction Costs and Benefits 

EPA must make a determination whether the risk of ocean acidification is unreasonable and this 

constitutes a balancing of costs and benefits. While it is EPA’s burden to conduct this analysis, 

petitioners present some limited data on (1) the socio-economic costs of CO2 pollution in light of 

ocean acidification, (2) the feasibility of controls on CO2 pollution, and (3) the social cost of 

carbon including the costs of delaying action to reduce and mitigate CO2 pollution. 

 

a. Socioeconomic Costs of Ocean Acidification 

The release of CO2 into the environment is already having social and economic impact, and these 

impacts are predicted to become even more concerning. Primary economic concerns are from the 

loss of fisheries and coral reefs. Ocean acidification also poses food security and nutrition risks. 

U.N. Convention on Biological Diversity estimated costs on the predicted damage of ocean 

acidification and predicts that the oceans will lose more than $1 trillion in value annually from 

ocean acidification (Convention on Biological Diversity 2014). CO2 related ocean warming and 

acidification will threaten marine food resources by disrupting marine communities, promoting 

harmful algal blooms and the spread of some diseases, and increasing contaminants in fish and 

shellfish (Tirado et al. 2010). 

The United Nations Environment Programme reported that ocean acidification’s impact on 

marine organisms is a threat to food security (UNEP 2010). The report documents that ocean 
28 

acidification is measurable and increasing, which poses a threat to fisheries resources and the 

billions of people that have a marine-based diet (United Nations Environment Programme 2010). 

Seafood has been shown to prevent hundreds of thousands of premature deaths, as well as 

significantly reduce infant morbidity; a decline of seafood availability will decrease 

these benefits. Some populations, including subsistence fishing populations and poor 

communities, depend on seafood and mortality and morbidity can result from the loss of these 

food sources (Mozaffarian 2006). For example, 95% of Alaskan households do some sort of 

subsistence fishing, and 17% of the state’s population, 120,000 people, depend on subsistence 

fishing (Mathis et al. 2014). Many subsistence fishers also have cultural ties threatened by ocean 

acidification. Accordingly, CO2 can result in social and environmental justice concerns that must 

also be assessed and weighed (Convention on Biological Diversity 2014). 

Not only will ocean acidification affect global food webs and ecosystems, it will have a direct 

effect on the global economy. The U.S. economy is very dependent on the health of the ocean. In 

2009, the ocean economy contributed over $223 billion annually to the U.S. gross domestic 

product and provided more than 2.6 million jobs (NOAA, 

http://oceanservice.noaa.gov/facts/oceaneconomy.html). Cooley and Doney (2009) estimate that 

if just a 10-25% decrease in United States mollusk harvests from 2007 were to occur today, $75-

187 million in direct revenue would be lost each year henceforth, with a net loss of $1.7-10 

billion through mid-century, when pH levels are approximately 0.3 units below pre-industrial 

values. In Washington State alone, the seafood industry generates $1.7 billion for gross state 

product and employs 42,000 people (Washington State Blue Ribbon Panel 2012). Already, 

shellfish hatchery failures in Washington have caused an economic stir and caused some 

hatcheries to relocate. Alaska’s commercial fishing industry is valued at over $4 billion a year, 

and supports 90,000 jobs—recreational fishing and fishing tourism add even more value. 

Meanwhile, Alaska is ranked among the most vulnerable areas to acidification. 

Tropical coral reefs provide ecosystem services, such as habitat and nursery functions for 

commercial and recreational fisheries and coastal protection. As reefs decline in acidified waters, 

there will be an ecological shift to a new ecosystem state dominated by less commercially 

valuable species. In 2009, Brander et al. estimated the annual economic damage of ocean 

acidification-induced coral reef loss to escalate rapidly over time, reaching $870 billion by 2100 

(Brander et al. 2009a). In 2014, Brander et al. increased the anticipated loss of ecosystem 

services from corals to be $1000 billion (UNEP 2014). Shoreline protection offered by coral 

reefs and the services it provides by preventing loss of life, property damage and erosion are also 

reduced by CO2 emissions. 

Lane et al. (2014) modeled three major U.S. locations for shallow water reefs -- South Florida, 

Puerto Rico, and Hawaii – to project future reef cover and the economic values generated by 

coral reefs for a greenhouse gas emissions mitigation scenario that represents international 

implementation of policies to reduce global emissions (resulting in a CO2 concentration of 427 

ppm in 2100), compared to a business as usual greenhouse gas emissions scenario resulting in a 

CO2 concentration of 785 ppm in 2100. The study estimated that reducing emissions would 

result in an “avoided loss” in Hawaii of approximately $10.6 billion in recreational use values 

compared to business as usual. Reducing emissions was projected to provide fewer economic 

benefits in Puerto Rico and South Florida, where sea-surface temperatures are already close to 
29 

bleaching thresholds and coral cover is projected to drop well below 5% cover under both 

scenarios by 2050, and below 1% cover under both scenarios by 2100 (Lane et al. 2014). 

As discussed previously, the toxicity of harmful algal blooms increases under conditions of 

ocean acidification. These toxins not only poison marine mammals, but also cause paralytic 

shellfish poisoning in people. Scientists hypothesize that some of the increases red tides off the 

coast of Southern California may be related to ocean acidification, though this has yet to be 

confirmed. In turn, harmful algal blooms cost the United States approximately $82 million each 

year from impacts to fisheries, public health, management, and lost recreational opportunities 

(Hoagland and Scatasta 2006). 

A recent study estimated that the damage our oceans will face from emissions-related problems 

will amount to $428 billion a year by 2050 and nearly $2 trillion per year by the century’s end 

(Noone et al. 2012). 

Acidification impacts processes so fundamental to the overall structure and 

function of marine ecosystems that any significant changes could have farreaching consequences for the oceans of the future and the millions of people that 

depend on its food and other resources for their livelihoods. 

(Doney et al. 2009). There is also a significant cost to delaying action. According to a recent 

report by the Council of Economic Advisers, delaying the implementation of policies to mitigate 

climate change could significantly increase economic damages, in addition to worsening 

environmental harm.39 

While there are still large unknowns on the biological consequences of ocean acidification, the 

science we have is clear: from shellfish to corals, and from pteropods to fish, our marine 

resources are threatened by the acidification of our ocean waters. 

b. Risk Reduction Methods 

There are several ways to reduce risk from CO2. EPA should use a suite of tools to reduce 

emissions, sequester CO2, mitigate harms, and promote alternatives. Under TSCA EPA has 

authority to:40

 prohibit or limit the amount of production or distribution of a substance in commerce; 

 prohibit or limit the production or distribution of a substance for a particular use; 

 limit the volume or concentration of the chemical produced; 

 prohibit or regulate the manner or method of commercial use; 

 require warning labels and/or instructions on containers or products; 

 require notification of the risk of injury to distributors and, to the extent possible, 

consumers; 

 

39 Executive Office of the President of the United States, The Cost of Delaying Action to Stem Climate Change at 1 

(July 2014). 

40 15 U.S.C. § 260. 
30 

 require record-keeping by producers; 

 specify disposal methods; and 

 require replacement or repurchase of products already distributed.

EPA also may impose any of these requirements in combination or for a specific geographical 

region. 41 Specifically, the agency must impose controls sufficient “to protect adequately against 

such risk using the least burdensome requirement.”42 

There is evidence that many industries could employ existing technology to achieve meaningful 

emissions reductions affordably. EPA’s own data demonstrate that lower pollution rates are 

readily achievable for many industrial sources of CO2. For example, the agency has identified 

dozens of “control measures and energy efficiency options that are currently available for pulp 

and paper mill processes,” ranging from technological upgrades to improved equipment 

maintenance.43 Similarly, EPA has compiled more than a decade of reports on “cost-effective” 

control strategies and other approaches available to reduce cement plant CO2 emissions, 

“includ[ing], for example, energy efficiency measures, reductions in cement clinker content, and 

raw materials substitution.”44 

Although cost-effective strategies to reduce CO2 emissions are available, existing controls have 

not reduced CO2 emissions sufficiently to protect against environmental harm. For example, 

most natural gas power plants have never exceeded the agency’s recently proposed emissions 

limit, thus indicating that existing and newly constructed facilities could easily satisfy a more 

stringent standard.45 Because energy-related CO2 pollution accounts for more than eighty percent 

of U.S. greenhouse gas production, readily achievable reductions in this sector would 

significantly benefit the environment.46 Similarly, the pulp and paper industry ranks among the 

largest consumers of energy,47 and emitted nearly 58 million metric tons of CO2 equivalent gases 

in 2004.48 Moreover, market incentives and regulatory controls are effective in increasing the 

rate of innovation for technologies that can reduce CO2 emissions. 

If a chemical presenting an unreasonable risk to health and the environment has already been 

distributed, EPA may prescribe procedures by which relevant manufacturers and purchasers must 

replace or repurchase that chemical.49 In the present situation, we urge the agency to exercise its 

 

41 Id. 42 15 U.S.C. § 2605(a). 

43 See EPA, Available and Emerging Technologies for Reducing Greenhouse Gas Emissions from the Pulp and 

Paper Industry at 11 (2010). 

44 EPA, National Emission Standards for Hazardous Air Pollutants From the Portland Cement Manufacturing 

Industry and Standards of Performance for Portland Cement Plants, 75 Fed. Reg. 54,970, 54,997 (Sep. 9, 2010). 

45 Ctr. for Biological Diversity, Comments on Standards of Performance for Greenhouse Gas Emissions from New 

Stationary Sources: Electric Utility Generating Units (Proposed Rule) Docket No. EPA-HQ-OAR-2013-0495 at 13-

14 (May 9, 2014). 

46 U.S. Dept. of State, U.S. Climate Action Report at 16 (2010). 47 See U.S. Energy Information Administration, First Use of Energy for All Purposes (Fuel and Nonfuel), 2010

(Mar. 2013), http://www.eia.gov/consumption/manufacturing/data/2010/#r1. 48 EPA, Available and Emerging Technologies for Reducing Greenhouse Gas Emissions from the Pulp and Paper 

Industry at 7 (2010). 

49 15 U.S.C. § 2605(a)(7)(C). 
31 

authority to remediate existing harm by requiring that responsible parties mitigate past CO2

emissions. 

There are numerous approaches to mitigating and sequestering CO2 emissions that EPA must 

evaluate. Effective land use and agricultural practices can significantly reduce carbon emissions 

and sequester CO2. Federal programs aimed at consumers can reduce CO2 emissions. For 

example, EPA’s Energy Star program has prevented 1.8 billion tons of greenhouse gas emissions 

by providing information that helps customers select energy efficient devices. Sequestration of 

CO2 in products, infrastructure, and waste management are among numerous methods that could 

be cost-effective to mitigate CO2 pollution.

c. Social Costs of Carbon 

In any analysis of the cost and benefits of reducing CO2 pollution, the costs of failing to address 

the problem of global warming should be included. Most efforts to quantify the social costs of 

carbon underestimate the real-world costs of CO2 pollution. Nevertheless, EPA may not ignore 

these costs. 

Global emissions must be less than 1000 Gt of CO2 between 2000 and 2050 to avoid dangerous 

climate change, which scientists have recommended that this means maintaining temperature 

change below 2° C.50 This means keeping atmospheric CO2 to 450 ppm, a threshold below which 

experts also use for ocean acidification (Veron et al. 2009; Silverman et al. 2009; Interacademy 

Panel 2009; McNeil & Matear 2008; Sea et al. 2007). For example, coral scientists predict that at 

450 ppm, reef-building will be severely diminished or will cease altogether (Veron et al. 2009). 

But the global community has already used a substantial portion of this CO2 budget, emitting 305 

Gt of CO2 between 2000 and 2008 alone.51 As a result, the years between now and 2020 have 

been dubbed the “critical decade.”52 Because carbon emissions must peak soon and decline 

thereafter, the sooner emissions peak, the less severe the subsequent annual reductions will need 

to be;53 correspondingly, if emissions are not sufficiently curbed in this decade, avoiding 

catastrophic damages will require much more drastic, disruptive and costly measures and may no 

longer be possible at all. Nonetheless, if action is taken immediately, it is both technologically 

and economically feasible to reduce emissions by 2020 and lay the groundwork for future 

emissions reductions.54 

Every year that the world delays its efforts to reach sustainable levels of greenhouse gas 

emissions represents a lost opportunity of tremendous economic significance. McKinsey & 

Company estimated in 2009 that for every year of delay, 1.8 Gt of potential CO2 abatement is 

foregone.55 This delay, and the accompanying Gts of lost CO2 abatement, has a price tag, as the 

 

50 Australia Department of Climate Change and Energy Efficiency, The Critical Decade: Climate Science, Risks and 

Responses at 53 (May 2011), available at http://www.scribd.com/doc/56043375/The-Critical-Decade-ClimateChange-Commision-Report. 51 Id. 52 Id. 53 UNEP, The Emissions Gap Report at 14 (Nov. 2010), available at 

http://www.unep.org/publications/ebooks/emissionsgapreport/; for a discussion of economic implications of these 

facts, see infra. 54 Id. at 23. 55 McKinsey & Company, Pathways to a Low-Carbon Economy: Version 2 of the Global Greenhouse Gas 

Abatement Cost Curve at 16 (2009), available at www.worldwildlife.org/climate/WWWFBinaryitem11334.pdf. 
32 

damage caused by CO2 emissions accelerate while the cumulative amount of greenhouse gases in 

the atmosphere rises, both because of the increasingly dire damages wrought by rising 

temperatures and other greenhouse gas effects, and because of the delay factor itself. If 

governments delay mitigation in the present, the emissions reduction curve in future years 

necessarily becomes much steeper, requiring much more drastic and costly emission reduction 

mechanisms with tremendous economy-wide disruptions, just to “catch up” with the lost 

opportunities from prior years to reach a sustainable emissions trajectory—or risk undergoing 

unsustainable climatic extremes. 

Economists have sought to quantify the costs of waiting to embark upon an emissions reduction 

path. In 2007, researchers used the DICE model56 to estimate the cost of delaying mitigation for 

a given period of time and then switching to an optimal abatement trajectory. According to their 

findings, the global cost of ten years of delay, relative to starting on an optimal trajectory in the 

present, ranges from hundreds of billions to several trillion dollars.57 For instance, this study 

estimates that it would cost somewhere between $200 and $400 billion dollars to delay action for 

ten years and then embark upon a mitigation strategy that would result in stabilization at 3 °C (a 

level now universally understood to far exceed the dangerous). The cost of delaying mitigation 

soars into the trillions of dollars as the delay continues, until it ultimately becomes impossible to 

achieve a certain level of temperature stabilization. According to this study, more than thirty 

years’ delay of changing the current course would make it impossible – no matter what the 

expense – to stabilize temperature rises at 2° C above pre-industrial levels. 

EPA and other federal agencies have been using the social cost of carbon to estimate the climate 

benefits of rulemakings since it was first developed by a dozen agencies (including USDA, CEQ 

and EPA) and published by the Interagency Working Group in 2010.58 The social cost of carbon, 

usually expressed as a dollar-per-ton figure, provides an estimate of the economic damages 

associated with an increase in CO2 emissions, conventionally one metric ton, in a given year. The 

dollar figure can also represent the value of damages avoided for emission reductions achieved 

by federal rulemakings. The social cost of carbon is designed to provide a comprehensive 

estimate of climate change damages, including, but not limited to, changes in net agricultural 

productivity, human health, and property damages from increased flood risk. However, given 

current modeling and data limitations, even EPA has conceded that that the social cost of carbon 

protocol is likely a conservative estimate because it does not yet account for all important 

damages.59 Nevertheless, the protocol is designed for use in regulatory processes like this one. In 

2013 the Federal Interagency Working Group increased its estimates of the social cost of carbon, 

using the same 3% annual discount rate, by 50%.60 The 2013 estimates are 50% higher for 

emissions in 2010, with greater percentage increases in subsequent years. Yet, even these social 

 

56 DICE stands for the Dynamic Integrated Climate and Economy model developed by William Nordhaus in 1990. 

57 Keller, K. et al., The Regrets of Procrastination in Climate Policy, Environmental Research Letters (2007), 

available at iopscience.iop.org/1748-9326/2/2/024004/. 58 EPA, The Social Cost of Carbon, http://www.epa.gov/climatechange/EPAactivities/economics/scc.html (last 

accessed June 28, 2015). 

59 Id. 60 Interagency Working Group on Social Cost of Carbon, United States Government, Technical Support Document: 

Technical Update of the Social Cost of Carbon for Regulatory Impact Analysis Under Executive Order 12866 (Nov. 

2013) at 3, available at http://www.whitehouse.gov/sites/default/files/omb/assets/inforeg/technical-updatesocialcost-of-carbon-for-regulator-impact-analysis.pdf. 
33 

cost of carbon figures significantly underestimate the true social cost of carbon, possibly by 

several orders of magnitude. 

Economists have noted that the social cost of carbon is far greater than the $21 per ton of CO2

assumed by interagency protocol in 2010 and greater than the 2013 revision.61 There are several 

inadequacies that make the values too conservative. Foremost, the models fail to evaluate ocean 

acidification—to the contrary the models consider the ocean a sink for CO2. The FUND model 

used in the Working Group’s analysis wholly excludes consideration of climate-induced 

catastrophic events. But the Working Group weighs the values generated by each of the three 

models equally, even though the FUND model’s values is significantly lower62 than the others, 

and consequently pulls down the final value of the social cost of carbon. The potential for 

catastrophic climate events, and the increasing likelihood that tipping points will be reached even 

sooner than anticipated, are increasingly serious risks, however, and, despite the associated 

uncertainties, must be fully represented in any evaluation of the social cost of carbon. Instead, 

the Working Group employed a risk-neutral approach, clearly inappropriate in light of the vast 

majority of scientific studies. Also, the models used fail to account fully or even partially for 

certain highly complex aspects of climate change, including the possibility of interrelations 

between different sectors and accelerating damage feedback loops, non-CO2 emissions,63 and 

social and political instability. Moreover, the valuation techniques and discount rates used to 

reach these values are inherently problematic and fail to represent the full value of all losses from 

climate change, in significant part because some cannot be reduced to monetary terms. 

Other evaluations of the social cost of carbon attempt to account for these omitted factors. The 

Stern Review, in particular, reaches a SCC of $85/ton of CO2 (in 2000 dollars).64 For comparison 

purposes with a Working Group value of $21 in 2005 dollars, this amount is equivalent to 

 

61 F. Ackerman & E. Stanton, Climate Risks and Carbon Prices: Revising the Social Cost of Carbon (2010) (the 

social cost of carbon could be over $800 per ton of CO2 equivalent; F. Ackerman & E. Stanton, Climate Risks and 

Carbon Prices: Revising the Social Cost of Carbon, in Economics, vol. 6 (Apr. 4, 2012) (reaching similar 

conclusions), available online at http://www.economics-ejournal.org/economics/journalarticles/2012-10 (last visited 

June 27, 2014); P. Epstein et al., Full cost accounting for the life cycle of coal, Ann. N.Y. Acad. Sci. (2011) 

(estimating the social cost of coal at between $10 and $100 per ton of CO2 equivalent); L. Johnson & C. Hope, The 

social cost of carbon in U.S. regulatory impact analyses: an introduction and critique, J. Envtl. Stud. & Sci. (Sept. 9, 

2012) (finding a social cost of a ton of CO2 emissions to be 2.6 to over 12 times larger than the Interagency 

Working Group’s central estimate of $21 per ton of CO2) available online 

athttp://link.springer.com/article/10.1007%2Fs13412-012-0087-7 (last visited June 27, 2014) E. Stanton et al., 

Comments on the 2013 Technical Update of the Social Cost of Carbon, January 27, 2014. 

62 Interagency Working Group on the Social Cost of Carbon, Social Cost of Carbon for Regulatory Impact Analysis 

Under Executive Order 12866, at 16-A-11, Fig. 16-A-4.2, available at 

http://www.rff.org/Publications/WPC/Pages/Estimating-the-Social-Cost-of-Carbon-for-Regulatory-ImpactAnalysis.aspx. 63 For instance, the estimated social cost of methane and SF6, are, respectively, $105/tonne and $200,000/tonne. See 

Intergovernmental Panel on Climate Change, Climate Change 2007 Synthesis Report 822, available at 

http://www.ipcc.ch/publications_and_data/ar4/syr/en/contents.html. For a critical analysis of the Working Group’s 

assumptions, see also Ackerman, F. and Stanton, E. A., The Social Cost of Carbon A Report for the Economics for 

Equity and the Environment Network (April 1, 2010), available at

http://www.e3network.org/papers/SocialCostOfCarbon_SEI_20100401.pdf. 64 Nicholas Stern, Stern Review on the Economics of Climate Change Part III: The Economics of Stabilisation at 

287 (2006), available at http://webarchive.nationalarchives.gov.uk/+/http:/www.hmtreasury.gov.uk/independent_reviews/stern_review_economics_climate_change/stern_review_report.cfm. 
34 

$96.25/ton in 2005. The Stern Review uses the PAGE model, which explicitly models for the 

risk of catastrophic climate change.65 In contrast with the Working Group, the Stern Review uses 

a mean temperature increase of 3.9 °C for its baseline scenario (consistent with the Third IPCC 

Report) and a 4.3 °C increase for its higher climate scenario. The resulting higher value of the 

social cost of carbon is thus very likely to be a closer approximation of the real cost of CO2. 

Meanwhile, the costs of reducing CO2 emissions are well worth taking prompt action. The 

“central estimates of the annual costs of achieving stabilisation between 500 and 550ppm CO2

are around 1% of global GDP, if we start to take strong action now. [...] It would already be very 

difficult and costly to aim to stabilise at 450ppm CO2e. If we delay, the opportunity to stabilise at 

500-550ppm CO2e may slip away.”'(Stern 2006). Likewise, the benefits of addressing CO2 for 

ocean acidification also have the ancillary effect of slowing global warming and preventing costs 

associated with climate change. 

The recently proposed rule to reducing power plant CO2 emissions calculates both costs and 

benefits—notably the benefits far exceed the costs. The recently proposed rules for reducing 

power plant carbon emissions, calculates both costs and benefits for a more modest reduction. 

EPA projects that the annual compliance cost will be $4.3 to $5.5 billion (in 2011 dollars, 

depending on discount rate) in 2020 and $5.5 billion (for a 5% discount rate) in 2030. 66 The 

total combined climate benefits and health co-benefits are estimated to be $15.6 to $88 billion in 

2020 and $32.3 to $151 billion in 2030 (depending on discount rate and the options chosen).67

The insurance industry also is well aware of the potential costs of failing to address CO2 

emissions and its associated effects, including: “[h]urricanes and other flooding events ... 

[h]ealth issues associated with heat waves... more airborne allergens, rising temperatures, 

greater humidity, more wildfires, and more dust and particulate pollution may considerably 

exacerbate upper respiratory disease (rhinitis, conjunctivitis, sinusitis, asthma) and 

cardiovascular disease.”68 A European insurance company estimates losses from extreme climate 

change events of 37% within a decade, over $1 trillion under bad circumstances.69 The 

increasing frequency and severity of storms in the U.S. has caused damages to increase 60-fold 

from 1950s to the 1990s.70

Petitioners ask that action to mitigate ocean acidification under TSCA be initiated, either through 

TSCA section 6 (e.g., requiring “repurchasing” relief using sequestration, emission reductions, 

etc.), or through section 4 in order to determine the need for action under section 6 and the most 

effective mitigation strategies. In any case, petitioners suggest that costs be apportioned among 

 

65 According to the Working Group itself, DICE “offers the best insight into the SCC if the world were to experience 

catastrophic climate change.” See Working Group, supra note 62, at 16-A-35. 66 EPA, Regulatory Impact Analysis Technical Document EPA-452/R-14-002 (June 2014). 

67 Id. 68 National Association of Insurance Commissioners, The Potential Impact of Climate Change on Insurance 

Regulation at 10 (2008). 

69 See e.g. Allianz, Climate Change and the Financial Sector: An Action Plan; Evan Mills, Responding to Climate 

Change: The Insurance Industry Perspective. 70 Mills, E. Insurance in a Climate of Change, Science 308: 1040 (2005). 
35 

CO2 emission contributors according to the cumulative CO2 emission inventory information EPA 

has collected.71 

*** 

In summary, the weight of the scientific information on ocean acidification is sufficient to make 

a determination that CO2 poses an unreasonable risk, to the extent that EPA declines to find the 

data adequate, then EPA must develop a test rule under TSCA section 4 as described below. 

C. Alternatively, EPA Must Require Testing to Develop Adequate Data 

EPA must make a determination as to whether adequate data exist to evaluate the environmental 

and health effects of CO2. There is well-established scientific information on the risk of CO2 on 

the environment, but if EPA determines that the data are insufficient then it must develop a 

testing rule. 

In enacting TSCA, Congress declared that “adequate data should be developed with respect to 

the effect of chemical substances and mixtures on health and the environment and that the 

development of such data should be the responsibility of those who manufacture and those who 

process such chemical substances and mixtures.”72 Accordingly, section 4 directs EPA to 

require additional testing upon determining that “the manufacture, distribution in commerce, 

processing, use, or disposal of chemical substance or mixture ... may present an unreasonable 

risk of injury to health or the environment,” or if the chemical is produced in substantial 

quantities and there is a potential for a substantial quality to be released into the environment.73 

1. CO2 May Present an Unreasonable Risk 

As described in depth in this petition, CO2 may present an unreasonable risk to the environment. 

EPA interprets this to mean that there is a “substantial (i.e., more than theoretical) probability" of 

unreasonable risk to the environment or health.74 The information in this petition meets the 

threshold for a testing rule and establishes a substantial probability that CO2 poses an 

unreasonable risk to the environment, but EPA need not even make such a determination because 

CO2 is produced in such large volumes that it clearly meets the criterion of exposure of 

substantial quantities being released into the environment. 

2. Substantial Quantities of CO2 Are Released into the Environment 

It is undeniable that substantial qualities of CO2 are released into the environment. EPA 

established a threshold value of one million pounds for a release of a chemical to be substantial. 

TSCA Section 4(a)(1)(B) Final Statement of Policy; Criteria for Evaluating Substantial 

 

71 This could be structured similar to the sponsorship format used in TSCAʼs High Production Volume (HPV) 

Program. 

72 15 U.S.C. § 2601(b)(1). 

73 15 U.S.C. § 2603 (a)(1)(A), (B)(i). 

74 Chemical Mfrs. Ass'n v. EPA, 859 F.2d 977, 988 (D.C. Cir. 1988). 
36 

Production, Substantial Release, and Substantial or Significant Human Exposure, 58 Fed. Reg. 

28736, 28746 (May 14, 1993). According to the IPCC: 

From 1750 to 2011, CO2 emissions from fossil fuel combustion and cement 

production have released 375 [345 to 405] GtC to the atmosphere, while deforestation 

and other land use change are estimated to have released 180 [100 to 260] GtC. This 

results in cumulative anthropogenic emissions of 555 [470 to 640] GtC. 

(IPCC 2013, Summary for Policymakers). 

In 2012, a total of 9.7 gigatonnes of CO2 were released into the atmosphere from fossil fuel 

combustion and cement production (Global Carbon Project 2013). These emissions are expected 

to increase to 9.9 gigatonnes in 2013 (Id.). The United States contributed 14% of CO2 emissions 

to the atmosphere (Id.). Models estimate that between 2003 and 2012, the oceans absorbed 27% 

of CO2 from the atmosphere (Id.). Over the next millennium, the oceans will absorb 90% of 

anthropogenic CO2 (Kleypas et al. 2006). 

Therefore, the threshold of substantial release is exceeded by more than a million times over. 

3. Recommendations for Testing 

EPA should consider a test rule to fill the information gaps needed to make a determination of 

whether CO2 presents an unreasonable risk of injury to the environment. Some recommendations 

for consideration include: 

 Testing CO2 reduction strategies. For example, research and development for 

emissions reduction strategies that include alternative practices, conservation, 

alternative fuels. Testing CO2 sequestration and capture approaches, and assessing 

attainable CO2 emissions reductions for industries with significant CO2 emissions. 

 Conducting a vulnerability assessment for marine and coastal species and ecosystems. 

Determining atmospheric CO2 levels necessary to conserve marine ecosystems from 

dangerous ocean acidification. Emissions scenarios are important for informing 

policy approaches to acidification.

 Forecasting species’ responses to ocean acidification using modeling tools to predict 

range shifts, demographic and population trends, and physiological responses across 

taxonomic groups using a range of climate models, emissions scenarios, and 

management timelines (25, 50, 100 years). Identify wildlife species and ecosystems 

imperiled by ocean acidification by evaluating range shift models and population 

viability models run under future ocean acidification levels. Recommend 

conservation actions, including protected status, for species that are most at risk. 

Protect species across their range since populations are likely to have different 

adaptations to local oceanic conditions.

 Determining the economic values of ecosystems that are at risk from ocean 

acidification and the costs of reducing CO2 emissions to preserve those ecosystems. 
37 

Additionally, EPA can use guidance on research needs based on existing research plans. There 

are a number of sources recommending research and data needs (National Research Council 

2013; Washington State Blue Ribbon Panel 2012; National Research Council 2010). 

According to TSCA, developing the data is “the responsibility of those who manufacture and 

those who process such chemical substances and mixtures.”75 For example, responsibility could 

be apportioned based on the historical carbon emissions from the EPA Greenhouse Gas Emission 

Inventory together with current emissions. Typically for test rules with multiple responsible 

parties consortiums are set up to comply.76 Here, for example, utilities, cement and lime 

manufacturers, waste incinerators, and other large producers of CO2 should be responsible for 

developing unbiased, independent data. 

While this may seem like a complicated undertaking, EPA has successfully completed more 

complex test rules. For example, from 1998 through the present, the agency used three sets of 

regulatory test rules under TSCA to collect chemical data for almost 3,000 high production 

volume (HPV) chemicals, including over 10,000 individual studies with data from domestic and 

foreign producers.77 

EPA must develop test rules under TSCA section 4 for research and data development focused 

on information essential for making a definitive TSCA section 6 finding. These would include 

risk, benefit and cost information. 

D. Inadequacy of Existing CO2 Reduction Strategies 

Petitioners are aware that the Agency has recently planned and initiated several emission 

reduction actions aimed at slowing the rate at which carbon emissions are increasing. However, 

these actions by themselves, while laudable, will not stabilize atmospheric CO2 at a level which 

will prevent widespread harm from ocean acidification. 

1. Global Greenhouse Gas Emissions Are Increasing Substantially 

The atmospheric concentration of CO2 reached 400 parts per million (ppm) for the first time in 

human history in May, 2013, compared to the pre-industrial concentration of ~280 ppm (Scripps 

Institution of Oceanography 2013). The current CO2 concentration has not been exceeded during 

the past 800,000 years and likely not during the past 15 to 20 million years (Denman et al. 2007; 

Tripati et al. 2009). Atmospheric CO2 emissions have risen particularly rapidly since the 2000s 

(Raupach et al. 2007; Friedlingstein et al. 2010). The global fossil fuel CO2 emissions growth 

rate was 1.0% per year in the 1990s compared with 3.1% per year since 2000, and this growth 

rate has largely tracked or exceeded the most fossil-fuel-intensive emissions scenarios projected 

by the IPCC (A1FI and RCP 8.5) since 2000 (Raupach et al. 2007, Peters et al. 2012). The CO2

emissions growth rate fell slightly in 2009 due largely to the global financial and economic 

 

75 15 U.S.C. § 2601 

76 15 U.S.C. § 2602 (b)(3)(A) 

77 EPA, High Production Volume (HPV) Challenge; http://www.epa.gov/chemrtk/index.htm (last accessed June 28, 

2015). 
38 

crisis; however, the decrease was less than half of what was expected and was short-lived 

(Fiedlingstein et al. 2010). In 2014 and 2015, global CO2 concentrations exceeded 400ppm.78 

2. U.S. Measures to Reduce Greenhouse Gas Emissions Are Insufficient 

EPA has taken some initial steps toward curbing greenhouse pollution under the Act. In 2009, 

the agency issued a formal finding that greenhouse pollution endangers public health and welfare 

and moved to limit emissions from passenger cars and trucks. The EPA also acknowledged that 

major new or modified “stationary” sources of greenhouse pollution, like power plants and 

factories, must obtain permits and control their emissions before beginning construction. 

However, it narrowed the scope of this requirement considerably under its so-called “tailoring 

rule,” which initially limits the permitting program to only a few hundred very large sources of 

greenhouse gases, letting a huge number of smaller — but still significant — sources off the 

hook. 

While existing domestic laws including the Clean Air Act, Energy Policy and Conservation Act, 

Clean Water Act, Endangered Species Act and others provide authority to executive branch 

agencies to require greenhouse gas emissions reductions from virtually all major sources in the 

United States, these agencies are either failing to implement or only partially implementing these 

laws for greenhouse gases. The landmark 2014 pact with China to reduce greenhouse gas 

emissions is significant, but there is little to ensure it is enforced and implemented. According to 

the plan, United States will reduce CO2 emissions 26 to 28% below 2005 levels by 2025. 

Proposed power plant rules also fail to do enough to cut CO2 pollution. Using the Clean Air Act, 

the president aims to reduce existing power plant emissions 30 percent below 2005 levels (or 

about 7.7 percent below 1990 levels, the base year for the international climate treaty) by 2030. 

But international scientists warned years ago that developed countries like the United States must 

reduce their emissions 25 percent to 40 percent below 1990 levels by 2020 to avoid tipping the 

scales further toward a climate catastrophe. Likewise, the recently announced plans to limit 

power plant emissions (Carbon Pollution Emission Guidelines for Existing Stationary Sources: 

Electric Utility Generating Units) focuses on emission reduction. Power plants are responsible 

for about a third of our carbon emissions, and the rule is designed to reduce those emissions by 

almost a third by 2030. This would result in a 10% decrease in 15 years. Stabilizing atmospheric 

concentration to prevent further acidification of the oceans would require about an 80% decrease 

in all emissions. Clearly this is a good first step, but by itself inadequate to address acidification. 

EPA has issued a rulemaking regulating greenhouse gas emissions from automobiles that will 

reduce greenhouse emissions emitted per vehicle mile traveled by passenger vehicles in the 

future. But because the improvements are modest and more vehicles are projected to drive more 

miles in the future, the rule will not reduce emissions from this sector overall but will only slow 

the rate of increase.79 Meanwhile, even the government concedes that “these reductions in 

emissions are not sufficient by themselves to reduce total HD vehicle emissions below their 2005 

 

78 NOAA, Trends in Atmospheric Carbon Dioxide, http://www.esrl.noaa.gov/gmd/ccgg/trends/ 79 EPA, Light-Duty Vehicle Greenhouse Gas Emission Standards and Corporate Average Fuel Economy Standards; 

Final Rule, 75 Fed. Reg. 25324 (May 7, 2010). 
39 

levels by 2020.”80 This means that the vehicle rule is far from achieving emissions goals agreed 

to by the U.S. in the Copenhagen Accord, which aim to keep global warming below 2 ̊C. 

The EPA has also to date issued only a single proposed rule under the new source pollution 

standard program for stationary sources of pollution, for electric generating units (power plants). 

While there is enormous potential to reduce emissions through this program overall and through 

the power plants rule in particular, the EPA has instead proposed a weak and flawed rule that it 

admits will not reduce emissions from these sources between now and 2020 compared to what 

would be expected without the rule.81 Indeed, in the rulemaking the EPA conceded that new 

power plant rule on greenhouse gas emissions “will not have direct impact on U.S. emissions of 

greenhouse gases under expected economic conditions.”82 

While full implementation of our flagship environmental laws, particularly the Clean Air Act, 

would provide an effective and comprehensive greenhouse gas reduction strategy, due to their 

non-implementation, existing domestic regulatory mechanisms must be considered inadequate to 

protect marine species from climate change and ocean acidification. 

3. International Measures to Reduce Greenhouse Gas Emissions Are 

Inadequate 

International initiatives are also currently inadequate to effectively address climate change. The 

United Nations Framework Convention on Climate Change, negotiated in 1992 at Rio de 

Janeiro, Brazil, provides the forum for the international negotiations. In the Framework 

Convention, signed and ratified by the United States, the world agreed to take the actions 

necessary to avoid dangerous climate change. Parties to the Convention also agreed as a matter 

of fairness that the world’s rich, developed countries, having caused the vast majority of 

emissions responsible for the problem, would take the lead in solving it. It was not until the 1997 

meeting in Kyoto, Japan, that the first concrete, legally binding agreement for reducing 

emissions was signed: the Kyoto Protocol. The Protocol requires the world’s richest countries to 

reduce emissions an average of 5 percent below 1990 levels by 2012, while developing nations 

also take steps to reduce emissions without being subject to binding emissions targets as they 

continue to raise their standard of living. The United States has been a major barrier to progress 

in the international negotiations. After the Clinton administration extracted many concessions 

from the rest of the world in exchange for the United States signing on in Kyoto, the Senate 

rejected the equity principles behind the Convention, saying the United States should not agree 

to reduce its own emissions unless all other countries — regardless of their responsibility or 

ability — were similarly bound. Citing the same excuses, President George W. Bush repudiated 

the Kyoto Protocol entirely. Thus the United States is the only industrialized country in the world 

that has yet to ratify the Kyoto Protocol. The United States negotiating team under both the 

George W. Bush and the Obama administrations has pursued two primary objectives in the 

international talks: to refuse any legally binding emissions reduction commitments until all other 

 

80 NHTSA, Medium- and Heavy-Duty Fuel Efficiency Improvement Program – Final Environmental Impact 

Statement (June 2011). 

81 EPA, Standards of Performance for Greenhouse Gas Emissions for New Stationary Sources: Electric Utility 

Generating Units, 77 Fed. Reg. 22392, 22430-33 (April 13, 2012). 

82 Id. at 22401. 
40 

countries— but particularly China and India — do so, and to push back the date for a new 

agreement. Not surprisingly, the United States had failed to meet its (never ratified) Kyoto 

pledge to reduce emissions to 7.2% below 1990 levels by 2012; to the contrary, U.S. emissions 

have increased by 10.5% since 1990 (EPA 2012). 

Moreover, the Kyoto Protocol’s first commitment period only sets targets for action through 

2012, and there is still no binding international agreement governing greenhouse gas emissions 

in the years beyond 2012. While the 2009 U.N. Climate Change Conference in Copenhagen 

called on countries to hold the increase in global temperature below 2C (an inadequate target for 

avoiding dangerous climate change), the non-binding “Copenhagen Accord” that emerged from 

the conference, and the subsequent “Cancún Accords” of 2010 and “Durban Platform” of 2011 

failed to enact binding regulations that limit emissions to reach this goal.83 Even if countries 

were to meet their Copenhagen and Cancún pledges, analyses have found that collective national 

pledges to cut greenhouse gas emissions are inadequate to achieve the 2°C target, and instead 

suggest emission scenarios leading to 2.5C to 5C warming (Rogelj et al. 2010; UNEP 2011; 

UNEP 2010). As of July 2013, many governments were not implementing the policies needed to 

meet their inadequate 2020 emission reduction pledges, making it more difficult to keep global 

temperature rise to 2C and likely leading to a temperature rise of at least 3.5C (USGCRP 

2013). As noted in the NMFS Management Report, the U.S. has yet to issue regulations to limit 

greenhouse gas emissions in accordance with its pledge under the Copenhagen Accord (NMFS 

2012). 

CONCLUSION 

In conclusion, this petition requires EPA to make a determination whether CO2 poses an 

unreasonable risk to the environment therefore requiring regulation under section 6 of TSCA. In 

an extensive review of the literature on the impact of ocean acidification on marine fauna and 

ecosystem processes, the authors found that while additional research is called for, sufficient 

information exists to state with certainty that deleterious impacts on some marine species are 

unavoidable, and that substantial alteration of marine ecosystems is likely over the next century. 

(Fabry et al. 2008). If, nonetheless, EPA determines that the information is insufficient to make 

such a finding it must develop testing rules pursuant to TSCA section 4. 

 

 

83 The non-legally binding Copenhagen Accord of 2009 and Cancún Accords of 2010 recognize the objective of 

limiting warming to 2°C above pre-industrial temperatures, but do not enact binding regulations to achieve this goal 

(http://cancun.unfccc.int/cancun-agreements/main-objectives-of-the-agreements/#c33; 

unfccc.int/resource/docs/2009/cop15/eng/11a01.pdf). According to the Durban Platform, developed and developing 

nations agreed to a process to develop a “new protocol, another legal instrument, or agreed outcome with legal force 

that will be applicable to all Parties to the UN climate convention”; this legal instrument must be developed as of 

2015 and will not take effect until 2020 (unfccc.int/resource/docs/2011/cop17/eng/l10.pdf). 
41 

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