Ocean Acidification: Frequently Asked Questions

November 3, 2022 – April 25, 2023 R47300

Ocean Acidification:
April 25, 2023
Frequently Asked Questions
Caitlin Keating-Bitonti
The ocean absorbs carbon dioxide (CO2) from the atmosphere. Chemical reactions between CO2
Analyst in Natural
and water can change the pH of seawater (pH is a measure of water’s acidity or basicity). The
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current shift in the chemistry of seawater is toward a lower pH, commonly referred to as ocean

acidification (OA). Scientific consensus is that rising CO2 concentrations in the atmosphere will
Eva Lipiec
continue to contribute to OA globally, primarily affecting the ocean’s surface waters, over the
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21st century. Other factors, such as seawater temperature and freshwater input, also can influence
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ocean acidification.

Certain U.S. regions are experiencing impacts from OA (e.g., coastal waters of Oregon), and

some scientists expect that nearly all U.S. coastlines and open ocean waters will experience
impacts of OA by 2100. In addition, some scientists project large freshwater bodies, such as the Great Lakes, may exhibit
acidification trends and impacts similar to those in the ocean by 2100. Impacts of OA include inhibiting the ability of some
marine organisms to grow their shells and corroding existing carbonate reef structures—a similar pattern is shown in the
fossil record from a period of widespread OA approximately 56 million years ago. These impacts to shell-building marine
organisms have had consequences for U.S. fisheries and aquaculture. Economic impacts of increased OA going forward may
include higher risks of storm damage to coastal communities and loss of tourism revenue from OA-caused degradation of
coral reefs.
Congress has authorized federal agencies, such as the National Oceanic and Atmospheric Administration (NOAA) and the
Environmental Protection Agency, to support activities that aim to adapt to and mitigate OA impacts. The Federal Ocean
Acidification Research and Monitoring Act (FOARAM; 33 U.S.C. §§3701 et seq.) was enacted in 2009. Among other things,
the law established the federal Interagency Working Group on Ocean Acidification (IWGOA) to coordinate OA activities
across the federal government. IWGOA’s work includes studying OA’s potential impact on marine species and ecosystems
as well as identifying adaptation and mitigation strategies.
Congress has continued to show interest in OA. For example, in 2022, Congress passed the Coastal and Ocean Acidification
Research and Innovation Act of 2021 (P.L. 117-167, Division B, Title VI, Subtitle E), which amended FOARAM. The
amendments added acidification of coastal waters as a concern to be addressed; established an advisory board to the IWGOA;
emphasized research on OA adaptation and mitigation strategies, the compounding effects of OA with other environmental
stressors, and the socioeconomic impacts of OA; and authorized appropriations for NOAA and the National Science
Foundation to conduct OA activities. Congress also has provided funding for certain OA activities. For example, Congress
specified funding to NOAA for OA activities in the explanatory statement accompanying the Consolidated Appropriations
Act, 2023 (P.L. 117-328).
Some Members of Congress have introduced, and congressional committees have considered, additional OA-related
legislation. For example, bills introduced during the 117th Congress focused on examining and addressing the impacts of OA,
among other activities. As another example, some Members have proposed legislation to increase federal engagement and
collaboration with tribes on OA issues in the 118th Congress.
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Introduction
Rising atmospheric carbon dioxide (CO2) levels impact the ocean in several ways, including by
altering its seawater chemistry. The increased uptake of atmospheric CO2 by the surface of the
ocean contributes to ocean acidification (OA).1 Parts of the ocean currently are experiencing OA,
and scientists project that OA will continue over the 21st century.2 The effects of OA vary
geographically, and with ocean depth, due to other factors that influence seawater chemistry.
Similarly, not all marine organisms will be impacted by OA in the same way; however, many
shell-building organisms are harmed by OA. U.S. ocean and coastal waters, as well as the Great
Lakes, are threatened by OA, and Congress has shown and continues to show interest in
addressing OA and its impacts. This report answers nine frequently asked questions about OA.
What Is Ocean Acidification?
Atmospheric gases, such as CO2, continuously diffuse into the surface of the ocean.3 Dissolved
gases in the surface of the ocean are in near equilibrium with gases in the atmosphere. Thus, as
more CO2 is emitted into the atmosphere, the surface of the ocean absorbs more CO2. Figure 1
shows the direct relationship between seawater CO2 concentrations (green data and line) and
atmospheric CO2 concentrations (red points and line). The increased uptake of atmospheric CO2
by the ocean alters the chemistry of seawater by decreasing its pH in a process referred to as
ocean acidification, or OA (blue data and line).4

1 Woods Hole Oceanographic Institution, “Ocean Acidification,” at https://www.whoi.edu/know-your-ocean/ocean-
topics/how-the-ocean-works/ocean-chemistry/ocean-acidification/.
2 Josep G. Canadell et al., “Chapter 5: Global Carbon and Other Biogeochemical Cycles and Feedbacks,” in Changing
Climate 2021: The Physical Science Basis, Intergovernmental Panel on Climate Change (IPCC), eds. Valerie Masson-
Delmotte et al., 2021, p. 720 (hereinafter referred to as IPCC, AR6 Physical Science Basis).
3 The surface mixed layer depth of the ocean varies seasonally and geographically but generally is between 0 and 200
meters beneath the surface of the ocean.
4 Rising carbon dioxide (CO2) emissions are the root cause for current surface ocean acidification (OA). In the ocean
interior, bacteria break down organic matter during cellular respiration, which adds CO2 to seawater (see “What
Factors Influence Ocean Acidification?”). National Oceanic and Atmospheric Administration (NOAA), “Ocean
Acidification,” at https://www.noaa.gov/education/resource-collections/ocean-coasts/ocean-acidification.
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Figure 1. Pacific Atmospheric and Seawater Carbon Dioxide Concentrations and
Seawater pH

Source: National Oceanic and Atmospheric Administration (NOAA), “Hawaii Carbon Dioxide Time-Series,” at
https://www.pmel.noaa.gov/co2/file/Hawaii+Carbon+Dioxide+Time-Series.
Notes: ppm = parts-per-mil ion, µatm = microatmosphere. Figure shows the relationship between atmospheric
carbon dioxide (CO2) concentrations (red points and line) and dissolved CO2 concentrations of seawater in
surface ocean (green points and line), as well as the relationship between increasing dissolved CO2
concentrations in surface ocean (green points and line) and decreasing seawater pH (blue points and line).
Atmospheric CO2 measurements were made at Mauna Loa Baseline Observatory (refer to Station Mauna Loa on
the insert map), which has been continuously monitoring and col ecting data related to atmospheric change since
the 1950s (NOAA, “Mauna Loa Baseline Observatory,” at https://gml.noaa.gov/obop/mlo/). Dissolved CO2 and
pH measurements were made at Station ALOHA, a circle of a 6-mile radius in the Pacific Ocean north of Hawaii
(refer to Station ALOHA on the insert map), which has been col ecting oceanographic data since 1988 (Station
ALOHA, at https://aco-ssds.soest.hawaii.edu/ALOHA/).
OA alters seawater chemistry following a series of chemical reactions. When atmospheric CO2
dissolves into water (H2O), it forms carbonic acid (H2CO3). Some of the carbonic acid breaks up
in ocean water, producing free hydrogen ions. As the number of free hydrogen ions increases, the
pH of the ocean decreases and the water becomes more acidic. The prevailing global average pH
(a measure of hydrogen ion concentration) of water near the ocean surface is around 8.1, with
regional variations.5

5 The pH scale is an inverse logarithmic representation of hydrogen ion concentration, indicating the activity of
hydrogen ions (or their equivalent) in the solution. A pH of less than 7.0 is considered acidic, a pH greater than 7.0 is
considered basic, and a pH level of 7.0 is defined as neutral.
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Ocean Acidification: Frequently Asked Questions

How Might Ocean Acidification Change over the
21st Century?
Over the past two centuries, the average pH of water near the ocean surface has decreased by
almost 0.1 unit.6 That change represents a 26% increase in the concentration of free hydrogen
ions dissolved in seawater, because the pH scale is logarithmic (i.e., water with a pH of 8.0 is 10
times less acidic than water with a pH of 7.0 and 100 times less acidic than water with a pH of
6.0).
Modeling studies project that OA will continue over the 21st century, but the rate of OA likely will
depend on the rate of atmospheric CO2 emissions.7 Under the Intergovernmental Panel on
Climate Change’s scenario involving a doubling of the concentration of atmospheric CO2 by
2050 based on no additional climate change policies, models project that average surface ocean
pH may decrease by 0.4 units by the year 2100 (see the maroon line in Figure 2).8 However,
using a scenario in which CO2 emissions reach net zero by 2050 or shortly thereafter, models
project that average surface ocean pH may decrease by less than 0.1 unit by 2050 and may rise
slightly in the second half of the 21st century (see the light and dark blue lines in Figure 2).9
Figure 2 also shows the projected pathway of ocean surface pH for other CO2 emissions
scenarios in modeling studies.10
Figure 2. Scenario Projections of Global Ocean Surface pH

Source: CRS with information from Intergovernmental Panel on Climate Change, “Summary for Policymakers,”
in Changing Climate 2021: The Physical Science Basis, eds. Valerie Masson-Delmotte et al., 2021, p. SMP-22.
Notes: CO2 = carbon dioxide; GHG = greenhouse gas. Model scenarios with intermediate to very high GHG
emissions (yellow, red, and maroon lines) project decreasing ocean surface pH through the 21st century. Other
model scenarios with very low to low GHG emissions (light and dark blue lines) project decreasing pH until
around 2070 that rises slightly after 2070. The light blue line holds global warming to about 1.5 degrees Celsius
(°C), in line with the goals of the Paris Agreement; the dark blue line holds global warming to beneath 2°C.

6 James Orr et al., “Anthropogenic Ocean Acidification over the Twenty-First Century and Its Impact on Calcifying
Organisms,” Nature, vol. 437 (2005); and NOAA, “Ocean Acidification,” at https://www.noaa.gov/education/resource-
collections/ocean-coasts/ocean-acidification.
7 IPCC, AR6 Physical Science Basis, Chapter 5, p. 720.
8 Ibid., p. 714.
9 Net-zero emissions means that some greenhouse gases (GHGs) are emitted, but these emissions are offset by
removing an equivalent amount of GHGs from the atmosphere and storing it permanently in soil, plants, or materials.
Achieving net-zero emissions may be considered more feasible than releasing no GHGs to the atmosphere (i.e., zero
emissions).
10 IPCC, AR6 Physical Science Basis, Chapter 5, p. 720.
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Model projections of average global OA changes, such as the projections shown in Figure 2, are
driven primarily by atmospheric CO2 simulations.11 In general, the global trend would reflect
surface pH decline with increasing atmospheric CO2 concentrations. Regional seawater properties
may influence the surface pH value, resulting in geographic variations in OA.12 See “What
Factors Influence Ocean Acidification?” for a further discussion on the factors that may amplify
regional variations in seawater pH.
What Factors Influence Ocean Acidification?
Not all ocean and coastal regions experience OA in the same way. Increased CO2 concentrations
in the atmosphere contribute to OA, but other factors also influence coastal and ocean
acidification. Rates of acidification can vary geographically for numerous reasons, including
temperature, ocean circulation, biological activity, coastal upwelling, freshwater input, nutrient
runoff, and atmospheric deposition, among other influences.13
 Temperature. Gases, such as CO2, are more soluble in colder water than in
warmer water. Thus, marine waters near the poles have a much greater capacity
to absorb atmospheric CO2 than do ocean waters in the tropics. As a
consequence, polar regions tend to experience greater regional changes due to
OA.14
 Ocean Circulation. Dissolved CO2 is transported from the ocean surface into
deeper ocean water at high latitudes, because cold polar surface waters have a
higher density than warm tropical waters. The cold polar surface waters sink to
depth (i.e., vertical ocean mixing), and both observations and modeling studies
show that the vertical ocean mixing contributes to acidification of the deeper
ocean.15 For example, OA below 2,000 meters has been detected in polar regions
in both the North Atlantic and the Southern Ocean.16
 Biological Activity. The breakdown of organic carbon in the ocean interior by
bacteria, via a biological process known as cellular respiration, adds CO2 to
seawater. Deep ocean water is enriched in CO2 due to cellular respiration, in
addition to the capacity of colder water in the deep ocean to absorb CO2.
Phytoplankton near the ocean surface and marine plants (i.e., kelp, seaweed,
seagrass) take up CO2 during photosynthesis, which may offset some effects of
OA.
 Coastal Upwelling. Coastal upwelling is a process by which coastal winds push
warm surface waters offshore, causing cold deep water to rise to the surface.
Upwelled ocean waters have high CO2 concentrations, because deep ocean
waters carry dissolved CO2 from two sources: (1) atmospheric CO2 from cold
polar waters that absorbed CO2 at the surface and sank to depth and (2) CO2

11 IPCC, AR6 Physical Science Basis, Chapter 5, p. 719.
12 Ibid.
13 IPCC, AR6 Physical Science Basis, Chapter 5, p. 720.
14 IPCC, AR6 Physical Science Basis, Chapter 5, p. 677.
15 IPCC, AR6 Physical Science Basis, Chapter 5, p. 717.
16 Ibid.
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respired by bacteria during the decomposition of organic carbon in the ocean
interior.17
 Freshwater Input. Riverine influx associated with high-intensity precipitation
events or glacial melt can yield large freshwater inputs that contribute dissolved
inorganic carbon, organic carbon, and nutrients to coastal waters. These
contributions can alter the chemistry of waters located at the mouths of large
rivers or the toes of glaciers. Rivers and streams also can deliver gases and
particles deposited within the watershed via atmospheric deposition (see below)
to freshwater bodies or coastal waters.
 Nutrient Runoff. Riverine inputs with high nutrient loads (often nitrogen and
phosphorous associated with farming practices) can lead to excessive plant and
algae growth in coastal settings, a process known as eutrophication.18 The
resulting decomposition of algae and plants in coastal waters produces increased
amounts of CO2 in the water column, which can lead to a lowering of seawater
pH.19
 Atmospheric Deposition. Fossil fuel combustion and biomass burning release
sulfur dioxide and nitrogen oxide gases to the atmosphere, where these gases are
chemically transformed into sulfuric acid and nitric acid.20 Wet atmospheric
deposition is commonly known as acid rain, and it includes any form of
precipitation (e.g., sleet, snow) that contains acidic compounds, such as sulfuric
and nitric acids.21 Uncontaminated precipitation (normal rain) is naturally acidic
with a pH of 5.6; acid rain generally has a pH between 4.2 and 4.4.22 Acid rain
plays a minor role in making the ocean more acidic on a global scale, but it can
have a greater impact on ocean coastal waters and freshwater systems.23
How Does Ocean Acidification Impact Marine Life?
The influence of OA on marine life is complicated. A pH of less than the global average of 8.1
may cause some organisms to expend more energy, but organisms may be able to adapt in
complex and species-specific ways to OA. OA may affect more marine species when its effects
are compounded by the effects of climate change, including warming seawater temperatures and
deoxygenation (loss of oxygen).24 In particular, OA poses physiological stress to invertebrate

17 U.S. Global Change Research Program (USGCRP), “Chapter 13: Ocean Acidification and Other Ocean Changes,”
in Climate Science Special Report: Fourth National Climate Assessment, vol. I, eds. Donald J. Wuebbles et al., 2017, p.
373 (hereinafter referred to as USGCRP, NCA4 vol. I). For a discussion on coastal upwelling, see CRS Report R47021,
Federal Involvement in Ocean-Based Research and Development, by Caitlin Keating-Bitonti.
18 U.S. Environmental Protection Agency (EPA), “The Sources and Solutions: Agriculture,” at https://www.epa.gov/
nutrientpollution/sources-and-solutions-agriculture.
19 NOAA, “What Is Eutrophication?,” at https://oceanservice.noaa.gov/facts/eutrophication.html.
20 Scott C. Doney et al., “Impact of Anthropogenic Atmospheric Nitrogen and Sulfur Deposition on Ocean
Acidification and the Inorganic Carbon System,” Proceedings of the National Academy of Sciences, vol. 104 (2007), p.
14580 (hereinafter referred to as Scott Doney et al., 2007).
21 EPA, “What is Acid Rain,” at https://www.epa.gov/acidrain/what-acid-rain.
22 Ibid.
23 Scott Doney et al., 2007, p. 14580, and EPA, “Effects of Acid Rain,” at https://www.epa.gov/acidrain/effects-acid-
rain.
24 IPCC, AR6 Physical Science Basis, Chapter 5, p. 721.
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organisms that build their hard parts (i.e., shells, skeletons, reef structures) with carbonate
minerals.25
Marine Invertebrates
For many marine invertebrate organisms, the abundance and availability of carbonate ions (CO 2-
3 )
in seawater are critical for survival. Most marine invertebrates have biochemical mechanisms to
regulate internal pH and are able, within limits, to grow and secrete their shells or exoskeletons
even when water in their surrounding environment is acidic. At current average ocean pH levels
(about 8.1), ocean waters near the surface have ample carbonate ions to support shell formation
and coral reef growth. However, as more CO2 dissolves into the ocean, the resulting chemical
reactions decrease the abundance and availability of carbonate ions.26 A reduction in the
availability of carbonate ions in the ocean makes it physiologically challenging for shell-forming
marine organisms to grow shells, especially those in early stages of their life cycle (i.e., larval and
juvenile stages). If the availability of carbonate ions becomes too low (i.e., undersaturated) in
seawater, then shells made with carbonate minerals tend to dissolve.
The following sections expound on current or potential impacts of OA on specific types of
invertebrate species, including corals, oysters, lobsters, and crabs.
Corals
OA reduces corals’ ability to build and maintain reefs, the majority of which are located in
tropical and subtropical shallow waters. Most corals are colonial organisms, comprising hundreds
to hundreds of thousands of individual animals, called polyps.27 Some polyps secrete carbonate
skeletons that can grow into very large reef structures, called coral reefs. Modeling studies
employing an emissions scenario in which very little climate change mitigation is undertaken this
century project seawater pH conditions by 2100 that are less favorable to the growth of coral reefs
(refer to the maroon line in Figure 2).28
Coral reefs are biodiverse, productive ecosystems that can provide socioeconomic benefits to
coastal communities. For example, studies show that reefs provide protection against erosion by,
and flooding from, waves comparable to that provided by artificial structures such as
breakwaters.29 Coral reef recreation and tourism also provide economic benefits for coastal
communities. For example, in 2015, reef-related tourism generated an estimated $217 million for
Puerto Rico and $108 million for the U.S. Virgin Islands.30 In addition to potential impacts on
tourism, declines in coral reef cover may reduce fisheries’ maximum catch potential in the

25 Carbonate minerals include aragonite, calcite, and high-magnesium calcite.
26 As more CO
1-
2-
2 dissolves into the ocean, bicarbonate ions (HCO3 ) form at the expense of carbonate ions (CO3 ),
which is described by the following reaction: CO
2-
1-
2 + CO3 + H2O = 2HCO3 .
27 NOAA, “What Are Corals?,” at https://oceanservice.noaa.gov/education/tutorial_corals/coral01_intro.html.
28 USGCRP, “Chapter 27: Hawai’i and U.S.-Affiliated Pacific Islands,” in Impacts, Risks, and Adaptation in the United
States: Fourth National Climate Assessment, vol. II, eds. David R. Reidmiller et al., 2018, p. 1264 (hereinafter referred
to as USGCRP, NCA4 vol. II); and K.L. Ricke et al., “Risks to Coral Reefs from Ocean Carbonate Chemistry Changes
in Recent Earth System Model Projections,” Environmental Research Letters, vol. 8 (2013), p. 5.
29 Filippo Ferrario et al., “The Effectiveness of Coral Reefs for Coastal Hazard Risk Reduction and Adaptation,”
Nature Communications, vol. 5 (2014); and U.S. National Park Service, “Breakwaters, Headlands, Sills, and Reefs,” at
https://www.nps.gov/articles/breakwaters-headlands-sills-and-reefs.htm.
30 USGCRP, NCA4 vol. II, Chapter 20, p. 829.
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exclusive economic zones of most central and western Pacific islands and in the Caribbean
region.31
Shellfish
OA’s effects on certain shellfish has impacted shellfish fishery revenues and may continue to do
so should OA expand to new regions and greater water depths.32 Of particular relevance to
shellfish hatcheries, relatively acidic ocean conditions caused by OA may impair the ability of
larval shellfish to build shells. For example, in the mid-2000s, oyster growers from Washington to
California experienced financial hardships from widespread death of larval shellfish (seed) at
hatcheries.33 In 2008, scientists from the National Oceanic and Atmospheric Administration
(NOAA) and various universities linked the oyster seed losses to OA; in turn, oyster hatcheries
shifted their operations to adapt to the OA conditions (see “What Are Federal Agencies Doing
About Ocean Acidification?”).34 An additional consideration regarding OA’s impact on oysters is
potential reductions in shell thickness and hardness, which could devalue oysters commercially
because shells that are easily shucked and do not break or chip (i.e., thick and hard shells) are a
sought-after characteristic of oysters on the half shell.35
OA also may affect other economically valuable shellfish, including the American lobster and
Dungeness crab. In 2021, the most recent year reported by NOAA Fisheries, the American lobster
found along the coast of New England was the highest-valued shellfish species in North
America.36 The Gulf of Maine, an area with record high stock abundance of American lobster,37
has experienced changing oceanographic conditions.38 Ocean warming has influenced lobster
fisheries in the region,39 and some research studies project the Gulf of Maine will experience OA
conditions by 2050.40 In the laboratory, researchers have shown that OA impacts both juvenile
and adult lobsters by causing erratic heart rates and fewer infection-fighting blood cells; should
these laboratory conditions occur in nature, they may impact lobsters’ survival.41

31 USGCRP, NCA4 vol. II, Chapter 27, p. 1264; and USGCRP, NCA4 vol. II, Chapter 20, p. 853.
32 Sarah Cooley and Scott Doney, “Anticipating Ocean Acidification’s Economic Consequences for Commercial
Fisheries,” Environmental Research Letters, vol. 4 (2009).
33 Ryan Kelly, “Narratives Can Motivate Environmental Action: The Whiskey Creek Ocean Acidification Story,”
Ambio, vol. 43 (2014), pp. 592-599.
34 Ibid. and NOAA, “Improving an Ocean Acidification Observation System in Support of Pacific Coast Shellfish
Growers,” at https://ioos.noaa.gov/project/turning-headlights-high/.
35 Catherine Liberti et al., “The Impact of Oyster Aquaculture on the Estuarine Carbonate System,” Elementa: Science
of the Anthropocene, vol. 10 (2022).
36 NOAA Fisheries reported a total commercial catch of nearly 134.7 million pounds of American lobster, yielding over
$924.7 million dollars, in 2021 (NOAA Fisheries, “Landings,” at https://www.fisheries.noaa.gov/foss/f?p=
215:200:14333709901427:Mail:NO, hereinafter referred to as NOAA Fisheries, Landings Database).
37 NOAA, “American Lobster,” at https://www.fisheries.noaa.gov/species/american-lobster.
38 Samantha Siedlecki et al., “Projecting Ocean Acidification Impacts for the Gulf of Maine into 2050: New Tools and
Expectations,” Elementa: Science of the Anthropocene, vol. 9 (2021).
39 Katherine Mills et al., “Fisheries Management in a Changing Climate: Lessons from the 2012 Ocean Heat Wave in
the Northwest Atlantic,” Oceanography, vol. 26 (2013), pp. 191-195.
40 Samantha Siedlecki et al., “Projecting Ocean Acidification Impacts for the Gulf of Maine into 2050: New Tools and
Expectations,” Elementa: Science of the Anthropocene, vol. 9 (2021).
41 Amalia Harrington and Heather Hamlin, “Ocean Acidification Alters Thermal Cardiac Performance, Hemocyte
Abundance, and Hemolymph Chemistry in Subadult American Lobsters Homarus americanus H. Milne Edwards, 1837
(Decapoda: Malcostraca: Nephropidae),” Journal of Crustacean Biology, vol. 39, no. 4 (2019), pp. 468-476.
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On the U.S. West Coast, Dungeness crabs are a valuable shellfish.42 Thus far, Dungeness crabs
have shown no change in natural population dynamics due to changing oceanographic conditions.
However, laboratory experiments have found decreased survival rates in Dungeness crabs
hatched in waters with a pH of 7.5 (a level that has been observed in upwelled waters along the
Washington coast) compared with those hatched in laboratory waters with a global average pH of
8.1.43
Marine Vertebrates
Whereas invertebrate organisms primarily build their hard parts (e.g., shells, carapace) with
carbonate minerals, vertebrate bones, including those of fish, are composed of a phosphate
mineral. OA does not affect the chemical structure of phosphate. Some studies, however, show
that the durability and robustness of some fish bones and shark teeth increase under OA
conditions.44 Other studies have claimed that OA can alter the behaviors of certain fish species,
but the research methodology behind these studies is debated.45
How Might U.S. Regions Be Affected by Ocean
Acidification?
Some U.S. regions have experienced measurable impacts from OA. Scientists expect that nearly
all U.S. coastlines will experience the impacts of OA by 2100.46 As shown in Figure 2, models
project a decrease in global ocean surface pH ranging from about 0.05 to 0.10 units by 2050. As
discussed above in “What Factors Influence Ocean Acidification?,” regional seawater properties
may affect the surface pH value, resulting in geographic variations of OA.
For example, Pacific waters along the U.S. West Coast are influenced by coastal upwelling.47
Observations and models project the California Current System may experience an expansion and
intensification of low-pH water due to upwelling.48 OA has impacted some oyster hatcheries
along the West Coast. In particular, in 2007, the Oregon-based Whiskey Creek Shellfish Hatchery
was unable to provide shellfish growers with late-stage oyster larvae because the low-pH

42 NOAA Fisheries reported a total commercial catch of nearly 69.3 million pounds of Dungeness crab in 2021,
yielding a total revenue of over $332.2 million for the Pacific Coast (NOAA Fisheries, Landings Database).
43 Nina Bednarŝek et al., “Exoskeleton Dissolution with Mechanoreceptor Damage in Larval Dungeness Crab Related
to Severity of Present-Day Ocean Acidification Vertical Gradients,” Science of the Total Environment, vol. 716 (2020);
and NOAA, “Dungeness Crab Larvae Already Showing Effects of Coastal Acidification,” January 23, 2020, at
https://research.noaa.gov/article/ArtMID/587/ArticleID/2581.
44 Jonathan Leung et al., “Shark Teeth Can Resist Ocean Acidification,” Global Change Biology, vol. 28, no. 7 (2022);
Valentina Di Santo, “Ocean Acidification and Warming Affect Skeletal Mineralization in a Marine Fish,” Proceedings
of the Royal Society B: Biological Sciences, vol. 268 (2019); and Alice Mirasole et al., “Evidences On Alterations in
Skeleton Composition and Mineralization in a Site-Attached Fish Under Naturally Acidified Conditions in a Shallow
CO2 Vent,” Science of the Total Environment, vol. 761 (2021).
45 See Martin Enserink, “Sea of Doubts,” Science (2021), at https://www.science.org/content/article/does-ocean-
acidification-alter-fish-behavior-fraud-allegations-create-sea-doubt.
46 USGCRP, NCA4 vol. I; and USGCRP, NCA4 vol. II.
47 For more information about ocean upwelling, see CRS Report R47021, Federal Involvement in Ocean-Based
Research and Development, by Caitlin Keating-Bitonti.
48 See “What Factors Influence Ocean Acidification” for more information about coastal upwelling. IPCC, AR6
Physical Science Basis, Chapter 5, p. 721.
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seawater corroded the shells of early stage larvae.49 Waters circulating around Alaska’s Pacific
coastline also are derived from upwelled cold waters and may be impacted by OA.50 Moreover,
glacial runoff may further amplify OA along the Alaskan coast (e.g., Gulf of Alaska).51
U.S. coastal regions near agricultural watersheds and urbanized estuaries may be susceptible to
OA due to eutrophication.52 For example, the Mississippi River delivers riverine inputs of
nutrients (nitrogen and phosphorus) to the Gulf of Mexico, contributing to eutrophication of
coastal waters and a decrease in pH along the Gulf coast.53 Similarly, runoff into the Chesapeake
Bay is contributing to eutrophication and a decrease in pH in the Bay’s waters.54 In addition,
coastal waters of the East Coast are influenced by freshwater inputs from riverine and estuarine
sources, which may contribute to OA.55
Tropical oceans are expected to experience the greatest change in seawater chemistry associated
with rising atmospheric CO2 concentrations.56 The seawater pH off the Hawaiian Island of Oahu
has declined from an annual average of about 8.11 in 1988 to 8.07 (roughly an 8.7% increase in
acidity), according to 35 years of ocean data collection at Station ALOHA (Figure 1).57 Although
oceanic pH varies geographically, scientists consider the conditions at Station ALOHA to be
broadly representative of those across the western and central Pacific Ocean.58 The tropical and
subtropical Pacific Ocean also is projected to experience the highest levels of thermal stress from
climate change, which could exacerbate the effects of increasing OA.59
Big freshwater systems, such as the Great Lakes, may be susceptible to acidification.60 The Great
Lakes are projected to experience acidification at a similar rate to the oceans by 2100 as a result
of atmospheric CO2 emissions.61 Currently, there are no long-term monitoring programs in the
Great Lakes that are designed to detect acidification.62

49 NOAA, “Improving an Ocean Acidification Observation System in Support of Pacific Coast Shellfish Growers,” at
https://ioos.noaa.gov/project/turning-headlights-high/; and R. Kelly, “Narratives Can Motivate Environmental Action:
The Whiskey Creek Ocean Acidification Story,” Ambio, vol. 43 (2014).
50 Jeremy Mathis, “Ocean Acidification Risk Assessment for Alaska’s Fishery Sector,” Progress in Oceanography, vol.
136 (2015).
51 Ibid; IPCC, AR6 Physical Science Basis, Chapter 5, p. 720.
52 NOAA, “What Is Eutrophication?,” at https://oceanservice.noaa.gov/facts/eutrophication.html.
53 IPCC, AR6 Physical Science Basis, Chapter 5, p. 721.
54 NOAA, “OPA Projects in the Southeast U.S.,” at https://oceanacidification.noaa.gov/CurrentProjects/
Southeast.aspx#.
55 USGCRP, NCA4 vol. I, Chapter 13, p. 373.
56 OA generally occurs in shallow ocean waters in tropical regions because there is little to no vertical ocean mixing to
transport the atmospheric CO2 absorbed by the surface ocean into the deep ocean.
57 Data collection and observations began at the Station ALOHA in October 1988.
58 John Marra and Michael Kruk, “State of Environmental Conditions in Hawaii and the U.S. Affiliated Pacific Islands
und a Changing Climate: 2017,” NOAA National Centers for Environmental Information, 2017, p. 74, at
https://coralreefwatch.noaa.gov/satellite/publications/state_of_the_environment_2017_hawaii-usapi_noaa-nesdis-
ncei_oct2017.pdf.
59 Ibid.
60 See, for example, Linda Weiss et al., “Rising pCO2 in Freshwater Ecosystems Has the Potential to Negatively Affect
Predator-Induced Defenses in Daphnia,” Current Biology, vol. 28 (2018).
61 Mark Rowe et al., “Great Lakes Region Acidification Research,” NOAA Ocean, Coastal, and Great Lakes
Acidification Research Plan: 2020-2029, 2020, p. 102 (hereinafter referred to as NOAA, Acidification Research Plan,
2020).
62 Ibid, p. 104. In 2022, NOAA’s Great Lakes Environmental Research Laboratory placed an instrumentation buoy in
the Thunder Bay National Marine Sanctuary to monitor Lake Huron’s water column carbon dioxide pressure and pH
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Has Ocean Acidification Happened in the Past?
OA has occurred in the past when geologic events (e.g., volcanic eruptions) emitted large
quantities of CO2 and other gases to the atmosphere. The fossil record suggests that some mass
extinction events of marine organisms that have occurred in geologic history may have been
related to changes in ocean pH. For example, approximately 56 million years ago, a large pulse of
methane locked in ocean sediments was released into the ocean-atmosphere system over a 3,000-
20,000 year period.63 Methane released into the ocean-atmosphere undergoes a chemical reaction
to become CO2 within about 10 years. Chemical analyses of marine sediments suggest this
methane release was associated with a global surface ocean pH decline ranging from 0.15 to 0.30
units. However, this change in pH occurred more slowly than the current rate of OA and
continued over a long time interval.64
What Actions or Interventions Might Limit or
Reduce Ocean Acidification?
Some stakeholders may be interested in limiting or reducing OA and its impacts. Mitigating OA
involves decreasing the availability of CO2 in the ocean by removing it from either the
atmosphere or the ocean. The ocean’s rate of uptake of atmospheric CO2 would start to decrease
if the concentration of atmospheric CO2 decreased.
Some shellfish industries have implemented approaches to mitigate CO2 concentrations in the
water. Some shellfish farmers on the Pacific and Atlantic coasts of the United States grow marine
plants (e.g., kelp, seaweed, seagrass) as a nature-based approach to offset the effects of OA.65
Researchers also are exploring an approach that involves placing bags of oyster shells near oyster
farms to improve the health of the living oysters.66 These researchers are testing the hypothesis
that, over time, the shells in the bags will dissolve and provide a natural buffer to OA. The
placement of oyster shells, or pulverized silicate or carbonate rocks, in seawater can alter the
water chemistry by fixing the CO2 dissolved in the seawater to the added material (i.e., shell,

level—both measurements are needed to study acidification. NOAA aims to expand the monitoring network in Lake
Huron and establish monitoring stations in Lakes Erie, Michigan, Ontario, and Superior. (John Flesher, “Scientists:
Atmospheric Carbon Might Turn Great Lakes More Acidic,” Associated Press, December 19, 2022, at
https://apnews.com/article/science-us-news-fish-plants-oceans-4db7ea795573e9d9260f6432b3e9b9f6, and NOAA,
Acidification Research Plan, 2020, p. 104).
63 Miriam Katz et al., “Uncorking the Bottle: What Triggered the Paleocene/Eocene Thermal Maximum Methane
Release?,” Paleoceanography, vol. 16 (2001); James Zachos et al., “Rapid Acidification of the Ocean During the
Paleocene-Eocene Thermal Maximum,” Science, vol. 308 (2005); and IPCC, AR6 Physical Science Basis, Chapter 5, p.
714.
64 IPCC, AR6 Physical Science Basis, Chapter 5, p. 714.
65 Marine plants remove CO
2 from the surface waters of the ocean via photosynthesis. See, for example, World
Wildlife Foundation, “Exploring the Benefits of Kelp Farming in Maine,” 2021, at https://www.worldwildlife.org/
magazine/issues/winter-2021/articles/exploring-the-benefits-of-kelp-farming-in-maine; and Marketplace, “Could Kelp
Help Mitigate Ocean Acidification?,” February 22, 2018, at https://www.marketplace.org/2018/02/22/could-kelp-help-
oyster-industry-mitigate-effects-ocean-acidification/.
66 NOAA, “Researchers Explore Using Empty Oyster Shells to Decrease Acidic Seawater,” October 13, 2017, at
https://seagrant.noaa.gov/News/Article/ArtMID/1660/ArticleID/1661/Researchers-Explore-Using-Empty-Oyster-
Shells-to-Decrease-Acidic-Seawater.
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pulverized rock or mineral). This approach for removing dissolved CO2 from the water is known
as ocean alkalinity enhancement or enhanced weathering.67
What Are Federal Agencies Doing About Ocean
Acidification?
Congress has shown interest in OA and its impacts over the past few decades and has directed
federal agencies to take certain actions to address OA.
Federal Agency Research and Monitoring Activities
In 2022, Congress amended the Federal Ocean Acidification Research and Monitoring Act of
2009 (FOARAM; P.L. 111-11).68 As amended, FOARAM
 Established and assigned responsibilities to the federal Interagency Working
Group on Ocean Acidification (IWGOA) and a nonfederal advisory board;
 Directed the Secretary of Commerce to establish an OA program within NOAA
and defined the program’s activities;69
 Instructed the National Science Foundation (NSF) to continue its OA research
activities, supporting competitive proposals for OA research, observation, and
monitoring;
 Charged the National Aeronautics and Space Administration with ensuring space-
based monitoring of OA and its impacts; and
 Authorized appropriations for NOAA and NSF to carry out these activities from
FY2023 through FY2027.70
The IWGOA released a strategic federal research and monitoring plan in 2014.71 In that plan, the
working group listed seven thematic areas of federal research and monitoring activities.72

67 National Academies of Sciences, Engineering, and Medicine, A Research Strategy for Ocean-Based Carbon Dioxide
Removal and Sequestration (Washington, DC: National Academies Press, 2022), p. 181. For more information on
ocean-based CO2 removal technologies, see CRS Report R47172, Geoengineering: Ocean Iron Fertilization, by Caitlin
Keating-Bitonti.
68 33 U.S.C. §§3701 et seq. See “What Are Recent Congressional Actions Addressing Ocean Acidification” for
information on the 2022 amendments.
69 Under statute, the federal Interagency Working Group on Ocean Acidification (IWGOA) is chaired by a
representative from NOAA and includes representatives from the National Science Foundation; National Aeronautic
and Space Administration; Smithsonian Institution; National Institute of Standards and Technology of the Department
of Commerce; EPA; Bureau of Indian Affairs, Bureau of Ocean Energy Management, National Park Service, U.S. Fish
and Wildlife Service, and U.S. Geological Survey of the Department of the Interior; U.S. Department of Agriculture;
Department of State; Department of Energy; Department of the Navy; and other agencies as appropriate.
70 The Federal Ocean Acidification Research and Monitoring Act of 2009 (FOARAM; P.L. 111-11), as amended, did
not specify an authorization of appropriations for the National Aeronautics and Space Administration.
71 IWGOA was charged with developing a strategic research and monitoring plan to guide federal research on OA and
overseeing the plan’s implementation (33 U.S.C. §§3703(a)(2)). IWGOA is to submit an updated plan to Congress at
least once every five years (33 U.S.C. §§3703(c)(3)). According to NOAA, a revised plan is forthcoming (email
correspondence with NOAA Office of Legislative and Intergovernmental Affairs, April 12, 2023).
72 IWGOA, Strategic Plan for Federal Research and Monitoring of Ocean Acidification, March 2014, at
https://oceanacidification.noaa.gov/Portals/42/Images/IWGOA Strategic Plan.pdf.
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1. Research to understand responses to OA
2. Monitoring of ocean chemistry and biological impacts
3. Modeling to predict changes in the ocean carbon cycle and impacts on marine
ecosystems and organisms
4. Technology development and standardization of measurements
5. Assessment of socioeconomic impacts and development of strategies to conserve
marine organisms and ecosystems
6. Education, outreach, and engagement strategy on OA
7. Data management and integration
The IWGOA’s 2016 report on implementation of the strategic plan identified multiple OA-related
activities across most of the IWGOA agencies.73 Of the seven thematic areas outlined in the 2014
strategic plan, most OA activities reported in 2016 were related to (1) research to understand
responses to OA and (2) monitoring of ocean chemistry and biological impacts.74 As of 2016 (the
latest update on implementation of the strategic plan), strategic plan actions remaining to be
addressed were (7) data management and integration.75
The IWGOA’s summary report for FY2018 and FY2019 (the most recent available) identified
funding levels by agency and research and monitoring activities by geographic area, with a focus
on locations of interest to the United States (Figure 3).76 Over the FY2012-FY2019 period, NSF
and NOAA reported the highest amount of OA activity funding in FY2019, with totals of $67.9
million and $29.3 million, respectively.77

73 According to the report, the Smithsonian Institution and the Department of Energy were not members of IWGOA in
2014, so their activities were not included in the 2016 implementation plan. In addition, the U.S. Navy did not
contribute to the document because its work on OA is “limited.” Activities of the Bureau of Indian Affairs also were
not included in the 2016 implementation plan. (National Science and Technology Council [NSTC] Subcommittee on
Ocean Science and Technology, Implementation of the Strategic Plan for Federal Research and Monitoring of Ocean
Acidification, December 2016, p. 33, at https://oceanacidification.noaa.gov/sites/oap-redesign/Documents/IWGOA/
OA%20Implementation%20Plan%20FINAL.pdf [hereinafter referred to as NSTC, Implementation Report, December
2016]).
74 NSTC, Implementation Report, December 2016, p. 3.
75 Ibid.
76 IWGOA, Sixth Report on Federally Funded Ocean Acidification Research and Monitoring Activities, October 28,
2022, pp. 27-28, 36, and 38 (hereinafter referred to as IWGOA, Sixth Report, October 2022). IWGOA is to submit
updated reports on implementation and funding to Congress every two years (33 U.S.C. §3703(c)(2)). According to
NOAA, revised reports are forthcoming (email correspondence with NOAA Office of Legislative and
Intergovernmental Affairs, April 12, 2023).
77 IWGOA, Sixth Report, October 2023, pp. 36, 38.
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Figure 3. Trends in Federal Funding of Ocean Acidification Research and Monitoring
Activities, FY2012-FY2019

Source: CRS, using Interagency Working Group on Ocean Acidification (IWGOA), Third Report on Federally
Funded Ocean Acidification Research and Monitoring Activities, April 23, 2015, pp. 20 and 25-26; IWGOA, Fourth
Report on Federally Funded Ocean Acidification Research and Monitoring Activities, December 20, 2016, pp. 43, 48, and
50; IWGOA, Fifth Report on Federally Funded Ocean Acidification Research and Monitoring Activities: Fiscal Years 2016
and 2017, January 28, 2020, p. 29; and IWGOA, Sixth Report on Federally Funded Ocean Acidification Research and
Monitoring Activities, October 28, 2022, pp. 27-28, 36, and 38.
Notes: Fiscal year total funding for ocean acidification research and monitoring for all IWGOA member
agencies that submitted information in that year, including the Bureau of Indian Affairs, Bureau of Ocean Energy
Management, Environmental Protection Agency, Department of State, National Aeronautics and Space
Administration, National Oceanic and Atmospheric Administration (NOAA), National Park Service, National
Science Foundation (NSF), Smithsonian Institution, U.S. Fish and Wildlife Service, and U.S. Geological Survey,
(solid black line); and for the two agencies with the most funding, NSF (dashed red line) and NOAA (dashed blue
line).
The IWGOA’s (sixth) summary report for FY2018 and FY2019 provides the most recent publicly available
funding levels. The IWGOA’s (fifth) summary report for FY2016 and FY2017 notes that the NSF contributions
are underreported. For example, ship support for NSF research activities is provided by NSF-funded University
National Oceanographic Laboratory System and is a major expense for OA activities; this expense was not
included in data used by CRS to create this figure.
NOAA is working on the summary report for FY2020 and FY2021 (email correspondence with NOAA Office of
Legislative Affairs, April 12, 2023).
Federal Agency Adaptation and Mitigation Activities
Federal agencies also support activities to adapt to and mitigate OA impacts.78 For example,
following the drop in oyster production levels at the Whiskey Creek Shellfish Hatchery in 2007,
NOAA deployed a network of sensors off the Northwest Pacific Coast to act as an early warning
system for shellfish hatcheries.79 The early warning system alerts hatchery managers when

78 For example, see NOAA Ocean Acidification Program, “Adaptation Strategies,” at
https://oceanacidification.noaa.gov/WhatWeDo/EducationOutreach/SOARCEWebinars/TabId/3463/PID/16157/evl/0/
CategoryID/207/CategoryName/adaptation-strategies/Default.aspx; and EPA, “What EPA Is Doing to Address Ocean
and Coastal Acidification,” at https://www.epa.gov/ocean-acidification/what-epa-doing-address-ocean-and-coastal-
acidification.
79 NOAA, “Improving an Ocean Acidification Observation System in Support of Pacific Coast Shellfish Growers,” at
https://ioos.noaa.gov/project/turning-headlights-high/; and R. Kelly, “Narratives Can Motivate Environmental Action:
The Whiskey Creek Ocean Acidification Story,” Ambio, vol. 43 (2014).
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upwelling produces relatively colder and lower pH seawater; these alerts allow hatchery
managers to time when coastal waters are pumped into the hatchery’s oyster larvae tanks or treat
the waters to avoid harming the oysters. Such early warning systems can help buffer the shellfish
industry against OA, as larvae grown at the hatchery are sold to commercial shellfish growers.
In another example, at the 2023 Our Ocean Conference in Panama, the United States (via the
Department of State) joined the International Alliance to Combat Ocean Acidification (OA
Alliance) and committed to drafting its national OA action plan. Members of the OA Alliance
committed to take individual actions that address the environmental, cultural, and economic threat
posed by OA by creating an action plan.80
In addition to the areas identified by the IWGOA in its 2014 strategic plan, the Ocean Policy
Committee (OPC) has noted other actions to address OA, such as engaging with vulnerable
communities, especially tribal communities, and ensuring that OA and its impacts are included in
discussions of potential solar geoengineering and carbon dioxide removal approaches.81 OPC also
identified other federal entities that may have a role in addressing OA, in addition to agencies in
the IWGOA, including the National Science and Technology Council Subcommittee on Ocean
Science and Technology and the National Security Council.82
What Are Recent Congressional Actions Addressing
Ocean Acidification?
In 2022, Congress passed the Coastal and Ocean Acidification Research and Innovation Act of
2021 (P.L. 117-167, Division B, Title VI, Subtitle E), which amended FOARAM. The
amendments included
 the addition of a definition for coastal acidification;83
 the addition of several federal agencies and departments to IWGOA;
 the establishment of an advisory board to IWGOA;
 a greater research focus on OA adaptation and mitigation strategies, on how OA
may interact with other environmental stressors, and on the socioeconomic
impacts of OA; and
 authorization of appropriations for FY2023 through FY2027.

80 U.S. Department of State, “United States Announces $800 Million in International Commitments for Protecting Our
Ocean,” press release, March 8, 2023, at https://www.state.gov/united-states-announces-800-million-in-international-
commitments-for-protecting-our-ocean/. In addition to the United States as a whole, nine U.S. states are members of
the OA Alliance and, of these nine states, California, Oregon, Maine, Washington, Maryland, and Hawaii have
completed their respective action plans. New Jersey, New York, and Virginia are the remaining alliance members. OA
Alliance, “Current Members,” at https://www.oaalliance.org/current-members, and OA Alliance, “Action Plans,” at
https://www.oaalliance.org/action-plans.
81 The Ocean Policy Committee coordinates federal actions on ocean-related matters and was codified by the National
Defense Authorization Act for Fiscal Year 2021 (P.L. 116-283, Title X, Subtitle E, §1055).
82 Ocean Policy Committee, Ocean Climate Action Plan, March 2023, p. 44, at https://www.whitehouse.gov/wp-
content/uploads/2023/03/Ocean-Climate-Action-Plan_Final.pdf.
83 The Coastal and Ocean Acidification Research and Innovation Act of 2021 (P.L. 117-167) amended the ocean
acidification definition in FOARAM and defined coastal acidification as “the decrease in pH and changes in the water
chemistry of coastal oceans, estuaries, and Great Lakes from atmospheric pollutions, freshwater inputs, and excess
nutrient run-off from land.”
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Congress also has provided direction to federal agencies regarding OA via the appropriations
process. For example, in FY2023, Congress appropriated $17 million to NOAA for the Integrated
Ocean Acidification Program.84 Language accompanying the FY2023 appropriations act directed
the agency to continue to work with state, local, territorial, and tribal governments on ocean and
coastal acidification research to complete vulnerability assessments required by FOARAM,85 and
to work with the White House Office of Science and Technology Policy to competitively award
prizes for innovation to understand, research, or monitor OA or its impacts, or to develop
management or adaptation options to respond to OA.86
Some Members of Congress have introduced additional legislation regarding OA in recent years.
For example, some bills in the 117th Congress would have directed the Secretary of Commerce or
NOAA to work with the National Academies of Sciences, Engineering, and Medicine to examine
the impact of OA and other environmental stressors on estuarine environments.87 One of these
bills also would have directed NOAA to support state and local OA vulnerability assessments and
strategic research planning related to OA and its impacts on coastal communities, among other
OA activities.88 Other bills would have included OA and its impacts as part of broader climate
change impacts or physical risks to be addressed in certain ways.89 As another example, in the
118th Congress, the proposed Coastal Communities Ocean Acidification Act of 2023 (H.R. 676)
would amend FOARAM to require federal engagement and collaboration with tribes.90

Author Information

Caitlin Keating-Bitonti
Eva Lipiec
Analyst in Natural Resources Policy
Analyst in Natural Resources Policy

84 “Explanatory Statement Submitted by Mr. Leahy, Chair of the Senate Committee on Appropriations, Regarding H.R.
2617, Division B—Commerce, Justice, Science, and Relate Agencies Appropriations Act, 2023, Consolidated
Appropriations Act, 2023,” Congressional Record, daily edition, vol. 168 (December 20, 2022), p. S7911. Hereinafter,
2023 Explanatory Statement Accompanying P.L. 117-328, Division B.
85 Ibid.
86 U.S. Congress, House Committee on Appropriations, Commerce, Justice, Science, and Related Agencies
Appropriations Bill, 2023, Report Together with Minority Views to Accompany H.R. 8256, 117th Cong., 2nd sess., June
30, 2022, H.Rept. 117-395, p. 43. The explanatory statement accompanying the 2023 Consolidated Appropriations Act
states that “Unless otherwise noted, the language set forth in House Report 117-395 (‘the House report’) carries the
same weight as language included in this joint explanatory statement and should be complied with unless specifically
addressed to the contrary in this joint explanatory statement or the act. The explanatory statement, while repeating
some language for emphasis, is not intended to negate the language referred to above unless expressly provided herein”
(2023 Explanatory Statement Accompanying P.L. 117-328, Division B, p. S7898).
87 For example, in the 117th Congress see H.R. 2533 (passed by the House on May 18, 2021) and H.R. 3764, Section
1011 (placed on the Union Calendar on December 30, 2022).
88 In the 117th Congress, H.R. 3764, Section 1011 (placed on the Union Calendar on December 30, 2022).
89 For example, in the 117th Congress, see H.R. 1187, Title IV (passed by the House on June 16, 2021), H.R. 2570
(placed on the Union Calendar on May 20, 2021), H.R. 2780, Section 301 (placed on the Union Calendar on December
30, 2022), H.R. 2872 (placed on the Union Calendar on November 16, 2022), and S. 1217 (hearings held by the Senate
Committee on Banking, Housing, and Urban Affairs on September 14, 2021).
90 In the 118th Congress, H.R. 676 was ordered to be reported by the House Committee on Science, Space, and
Technology on March 29, 2023.
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