There is high confidence that increasing ocean temperatures, changes in ocean acidity, and changes in the frequency and intensity of storms are extremely likely to affect coastal and marine resources. Large storm events within the past decade have resulted in significant effects on marine resources, particularly coral habitats and organisms that rely on them. There is medium confidence in predictions that coral habitats will likely continue to decline throughout the Caribbean, with associated effects on resources dependent on these habitats; although, scientific studies are still needed in terms of climate change effects on fisheries resources, particularly for species that are found in offshore waters or are pelagic. Changes in coral habitats are already occurring as evidenced by massive coral bleaching events (including a three-year global-level bleaching event from 2015–2017) and the increase in these events. Such changes in bleaching events are due to rising sea surface temperatures. There is high confidence that there have been changes in ocean pH and medium confidence on the ecological effects. Due to the lack of studies on the social consequences of climate change and associated losses of resources such as fisheries, there is medium confidence that effects on coastal and marine resources resulting from climate change will affect island economies. These effects can be a result of changes in availability and condition of fishery resources, loss of reefs and other coral communities that serve as coastal barriers, and effects on tourism due to loss of the resources that are primary attractions for visitors.
There is medium confidence in the ecological effects that will result due to changes in ocean pH. The CO2 system of seawater is well understood and established. As such, the understanding of the basic equilibria governing the process of ocean acidification dates back to at least 1960{{< tbib '168' 'b20e8c2b-cfb8-48b6-85c6-c981c361e267' >}} and represents a foundational understanding of modern chemical oceanography. The ecological consequences of human-induced changes to the system (that is, ocean acidification) is, however, a considerably new field. Both themes were assessed considering recent findings and based on adequate observed local data (for example, atmospheric pCO2 [carbon dioxide partial pressure] values are based on measurements of weekly air samples from St. Croix, the USVI, the United States, and Ragged Point, Barbados), complemented with empirical models. Projected changes in climate for the Caribbean islands were based on the future projections of fossil fuel emissions driven by reasonable models from the Intergovernmental Panel on Climate Change (IPCC).{{< tbib '169' 'bc140b4c-c2d9-4d99-a684-5c054dc5134f' >}} Additional empirical species response data would be useful for increasing the understanding of expected effects of ocean acidification on species and habitats in the Caribbean.
" contributors: [] evidence: "In 2006, the National Marine Fisheries Service (NMFS) listed elkhorn and staghorn corals as threatened species under the Endangered Species Act, with persistent elevated sea surface temperatures and sea level rise being two of the key factors influencing the listing decision.{{< tbib '158' '9d974b61-97ea-4778-977d-26701052c8e9' >}} The Acropora Biological Review Team (2005) found that the number of hurricanes affecting reef ecosystems in the Caribbean has increased over the past two decades (2 hurricanes in the 1970s, 6 in the 1980s, and 12 in the 1990s). Sea surface temperature is expected to continue rising, and this implies an increasing threat to elkhorn and staghorn corals from bleaching-induced mortality and possibly an exacerbation of disease effects. In 2014, NMFS listed an additional 5 species of Atlantic/Caribbean corals (lobed, mountainous star, boulder star, pillar, and rough cactus) as threatened and reevaluated the listing of elkhorn and staghorn corals, confirming them as threatened species; it also listed 15 Indo-Pacific coral species as threatened,{{< tbib '159' '8960de56-9b32-4544-9255-046a9ef45e0d' >}} with two of the key factors being ocean warming and ocean acidification. Brainard et al.{{< tbib '159' '8960de56-9b32-4544-9255-046a9ef45e0d' >}} found that ocean warming and related effects of climate change have already created a clear and present threat to many corals that will likely continue into the future and can be assessed with certainty out to 2100. Increases in human population densities and activity levels in the coastal zone are expected to continue, meaning the vulnerability of these populations and infrastructure will likely continue increasing with climate change.{{< tbib '160' '895e2c92-d614-4154-8509-7689918c8697' >}} Direct measurements at the Bermuda Atlantic Time-series Study station shows that surface ocean acidity has increased by about 12% and aragonite saturation (Ωarg) has decreased by about 8% over the past three decades.{{< tbib '161' 'ade3d353-6612-4e45-96d3-9269de56eda0' >}} These values agreed with those reported across the Caribbean{{< tbib '162' '0e312df5-ad3d-4709-8b58-8cea86d26415' >}} and Atlantic regions{{< tbib '18' 'd51156cc-0034-4afc-b2b7-1ad99efde458' >}},{{
Many coastal regions already experience low surface seawater pH and Ωarg conditions (localized or coastal ocean acidification) due to processes other than CO2 uptake. As a result, the effect of ocean acidification on coastal zones can be several times higher and faster than typically expected for oceanic waters.{{< tbib '163' 'dc5e5365-8b0f-4a21-93b4-c6a822be824d' >}}
Caribbean coral reefs in the Bahamas, Belize, Bonaire, and Grand Cayman are already experiencing significant reductions in carbonate production rates, with 37% of surveyed sites showing net erosion.{{< tbib '164' '0841a7ce-1022-4cf7-be4f-5c20d3b19f2a' >}} Friedrich et al. (2012).{{< tbib '66' 'a03f3916-2084-4353-bce4-adac93801617' >}} concluded that calcification rates may have already dropped by about 15% within the Caribbean with respect to their preindustrial values.
" files: [] gcmd_keywords: - definition: 'An ecosystem is a community of living organisms in conjunction with the nonliving components of their environment (things like air, water and mineral soil), interacting as a system. These biotic and abiotic components are regarded as linked together through nutrient cycles and energy flows. As ecosystems are defined by the network of interactions among organisms, and between organisms and their environment, they can be of any size but usually encompass specific, limited spaces. (although some scientists say that the entire planet is an ecosystem.' href: https://data.globalchange.gov/gcmd_keyword/f1a25060-330c-4f84-9633-ed59ae8c64bf.yaml identifier: f1a25060-330c-4f84-9633-ed59ae8c64bf label: ECOSYSTEMS parent_identifier: 91c64c46-d040-4daa-b26c-61952fdfaf50 uri: /gcmd_keyword/f1a25060-330c-4f84-9633-ed59ae8c64bf - definition: |- Related to the act, process, or season of catching a species of fish or a group of species in marine and non-marine environments, excludes fish farming, hatcheries, and other aquaculture. href: https://data.globalchange.gov/gcmd_keyword/fa57b0a0-9723-4195-bdd1-4f26aefa0e07.yaml identifier: fa57b0a0-9723-4195-bdd1-4f26aefa0e07 label: FISHERIES parent_identifier: f27ad52c-3dfd-4788-851a-427e60ae1b8f uri: /gcmd_keyword/fa57b0a0-9723-4195-bdd1-4f26aefa0e07 - definition: 'Any measurement or statistic of, related, or based on the production, distribution, and consumption of goods and services.' href: https://data.globalchange.gov/gcmd_keyword/cdbe5ef5-408d-489d-b6ff-4482ce4a99c7.yaml identifier: cdbe5ef5-408d-489d-b6ff-4482ce4a99c7 label: ECONOMIC RESOURCES parent_identifier: fb93d937-c17c-45d0-a9e3-ca5c8a800ca8 uri: /gcmd_keyword/cdbe5ef5-408d-489d-b6ff-4482ce4a99c7 - definition: Describes an activity that diverts or amuses or stimulates. It can also be described as an activity that renews health and spirits by enjoyment and relaxation. href: https://data.globalchange.gov/gcmd_keyword/9ee8acad-458e-45c1-a1d5-9b1649c82ea7.yaml identifier: 9ee8acad-458e-45c1-a1d5-9b1649c82ea7 label: RECREATIONAL ACTIVITIES/AREAS parent_identifier: c8317644-4cb2-4e37-b536-c762f7e670ab uri: /gcmd_keyword/9ee8acad-458e-45c1-a1d5-9b1649c82ea7 - definition: |- A measure of the average kinetic energy of the vibration of water molecules, measured or estimated at the sea surface. href: https://data.globalchange.gov/gcmd_keyword/bd24a9a9-7d52-4c29-b2a0-6cefd216ae78.yaml identifier: bd24a9a9-7d52-4c29-b2a0-6cefd216ae78 label: SEA SURFACE TEMPERATURE parent_identifier: 251c87cd-03b3-464f-8390-8ede2fec28fc uri: /gcmd_keyword/bd24a9a9-7d52-4c29-b2a0-6cefd216ae78 - definition: |- A measure of the alkaline or acid strength of a substance. pH is defined as the logarithm of the reciprocal of the hydrogen ion concentration of a solution. href: https://data.globalchange.gov/gcmd_keyword/4433600b-f323-458a-b295-352f939aab6b.yaml identifier: 4433600b-f323-458a-b295-352f939aab6b label: PH parent_identifier: 6eb3919b-85ce-4988-8b78-9d0018fd8089 uri: /gcmd_keyword/4433600b-f323-458a-b295-352f939aab6b - definition: An increase in the average height of the sea surface over a vertical datum. href: https://data.globalchange.gov/gcmd_keyword/0afaaa5e-f88c-4c1f-95c1-1faa0148885a.yaml identifier: 0afaaa5e-f88c-4c1f-95c1-1faa0148885a label: SEA LEVEL RISE parent_identifier: b6fd22ab-dca7-4dfa-8812-913453b5695b uri: /gcmd_keyword/0afaaa5e-f88c-4c1f-95c1-1faa0148885a - definition: 'A violent disturbance of the atmosphere with strong winds and usually rain, thunder, lightning, or snow.' href: https://data.globalchange.gov/gcmd_keyword/ad28623e-bb9b-433c-8fc1-2ab06dda58c4.yaml identifier: ad28623e-bb9b-433c-8fc1-2ab06dda58c4 label: SEVERE STORMS parent_identifier: ec0e2762-f57a-4fdc-b395-c8d7d5590d18 uri: /gcmd_keyword/ad28623e-bb9b-433c-8fc1-2ab06dda58c4 - definition: 'Underwater structures made from calcium carbonate secreted by corals. Corals are colonies of tiny living animals found in marine waters containing few nutrients. Most coral reefs are built from stony corals, and are formed by polyps that live together in groups. The polyps secrete a hard carbonate exoskeleton which provides support and protection for the body of each polyp.' href: https://data.globalchange.gov/gcmd_keyword/dff4d4af-e1e0-4991-884b-a1c088a802b2.yaml identifier: dff4d4af-e1e0-4991-884b-a1c088a802b2 label: CORAL REEFS parent_identifier: c58320e6-3f1d-4c36-9bee-6bad73404c21 uri: /gcmd_keyword/dff4d4af-e1e0-4991-884b-a1c088a802b2 - definition: 'The loss of intracellular endosymbionts (Symbiodinium, also known as zooxanthellae) through either expulsion or loss of algal pigmentation.' href: https://data.globalchange.gov/gcmd_keyword/f5df87b6-ed50-4da0-9ba5-7ce4c907bdb3.yaml identifier: f5df87b6-ed50-4da0-9ba5-7ce4c907bdb3 label: CORAL BLEACHING parent_identifier: ad497e7a-48fa-45e1-90a5-b052508bdb30 uri: /gcmd_keyword/f5df87b6-ed50-4da0-9ba5-7ce4c907bdb3 href: https://data.globalchange.gov/report/nca4/chapter/us-caribbean/finding/key-message-20-2.yaml identifier: key-message-20-2 ordinal: 2 parents: [] process: 'The majority of our Key Messages were developed over the course of two separate author meetings. The first occurred March 9–10, 2017, and the second on May 3, 2017. Both meetings were held in San Juan, Puerto Rico; however, people were also able to join remotely from Washington, DC, Raleigh, North Carolina, and the U.S. Virgin Islands (USVI). In addition, the author team held weekly conference calls and organized separate Key Message calls and meetings to review and draft information that was integral to our chapter. To develop the Key Messages, the team also deliberated with outside experts who are acknowledged as our technical contributors.
Marine ecological systems provide key ecosystem services such as commercial and recreational fisheries and coastal protection. These systems are threatened by changes in ocean surface temperature, ocean acidification, sea level rise, and changes in the frequency and intensity of storm events. Degradation of coral and other marine habitats can result in changes in the distribution of species that use these habitats and the loss of live coral cover, sponges, and other key species (very likely, high confidence). These changes will likely disrupt valuable ecosystem services, producing subsequent effects on Caribbean island economies (likely, medium confidence).
' uncertainties: "The link between climate stressors such as increasing sea surface temperatures and bleaching response and increasing prevalence of disease in corals is postulated. There is some scientific evidence indicating a link, but it is hard to make definitive conclusions. Effects of climate change on fisheries in the Caribbean have not been as well studied as the effects on marine habitats, particularly coral reefs.{{< tbib '74' '94f95306-0dd9-43cf-8e70-9a379423f31d' >}},{{
Uncertainty with respect to ocean acidification is dominated by uncertainty about how ecosystems and organisms will respond, particularly due to multiple interactions with other stressors.
The value of the loss of ecosystem services to ocean acidification is unknown. Such losses are attributable to the degradation of ecosystems that support important economic marine species such as coral, conch, oysters, fish larvae, urchins, and pelagic fish in the Caribbean. There is strong evidence for decreasing carbonate production, calcification rates, coral cover, and biomass of major reef-building species throughout the Caribbean region. However, there is still not enough evidence to conclude that all these decreased ecosystem processes are due to ocean acidification.
There are only a few studies on ecosystem and organism responses to climate stressors (such as ocean warming) that consider ocean acidification in the Caribbean. For instance, low pH values could affect nursery areas of commercially important species such as tuna, presenting a source of vulnerability for the economy, but studies are scarce. Ocean acidification could also affect the food web dynamics at lower trophic levels and have physiological effects at larval stages that would likely cascade upward, affecting coral and fish recruitment.
The effects of ocean acidification on coral reefs, shellfish, fish, and marine mammals will likely cause an economic effect on fisheries, coastal protection, and tourism in the Caribbean. Ocean acidification can exacerbate the current global warming effects on coral reefs, and it will likely continue deteriorating reef conditions and cause ecological regime shifts from coral to algal reefs.{{< tbib '77' 'b09adbe5-6a17-4d3c-ab96-b3d9e306af67' >}},{{
Sea level rise is currently the most immediate and well-understood climate-related threat to mangroves.{{< tbib '70' 'c527429c-5661-477a-a6f4-1690355bcbd5' >}} It is not clear how mangroves will respond to elevated CO2, and some studies suggest increases may actually be beneficial to mangroves.{{< tbib '70' 'c527429c-5661-477a-a6f4-1690355bcbd5' >}} Similarly, in the Caribbean where temperatures are already high, increasing temperatures, as well as declines in rainfall and corresponding increases in soil salinity during periods of drought, will likely increase plant water stress and reduce productivity. There have been limited studies on the effects of climate change on seagrass beds; therefore, these effects remain uncertain.{{< tbib '69' '63aac7f9-5e82-4aff-ab62-75c12537612f' >}} Sea level rise that results in reduced sunlight due to increased water depths can lead to the loss of seagrass beds from deeper waters. As discussed previously, the loss or degradation of these habitats, which are part of the coral reef ecosystem and serve as nursery habitat for important nursery species, will likely contribute to declines in fishery productivity due to climate change.
" uri: /report/nca4/chapter/us-caribbean/finding/key-message-20-2 url: ~