Will the Oceans Become Acidic in the Future?

Check out this answer from Consensus:

Ocean acidification poses a serious threat to marine ecosystems, with potential impacts on a wide range of marine organisms and the services they provide. While some species may show resilience or even benefit from the changing conditions, the overall outlook suggests significant ecological disruptions. Immediate action to reduce CO2 emissions is crucial to protect the health and stability of the world’s oceans.

The phenomenon of ocean acidification (OA) is a significant consequence of increased atmospheric CO2 levels. As CO2 is absorbed by the world’s oceans, it leads to a series of chemical reactions that lower the pH of seawater, making it more acidic. This article explores the current understanding of ocean acidification, its potential impacts on marine ecosystems, and the future outlook based on recent scientific research.

The Chemistry of Ocean Acidification

Ocean acidification is primarily driven by the absorption of CO2 from the atmosphere. When CO2 dissolves in seawater, it forms carbonic acid, which subsequently dissociates into bicarbonate and hydrogen ions, leading to a decrease in pH. This process has already resulted in a 30% increase in the concentration of H+ ions in ocean surface waters since the early 1900s, and projections suggest a potential drop in seawater pH of up to 0.5 units by 21004.

Impacts on Marine Life

Echinoderms

Echinoderms, such as sea stars and sea urchins, are vital components of marine ecosystems. Studies indicate that while some echinoderm species show resilience to OA, others experience significant negative impacts, particularly in long-term exposure scenarios. These impacts include developmental abnormalities and reduced fitness, which could have profound ecosystem-level consequences1 9.

Molluscs

Molluscs, including mussels and oysters, are particularly vulnerable to ocean acidification. The reduction in carbonate ion concentration, essential for shell formation, poses a significant threat to these species. The potential sub-lethal impacts on molluscs could disrupt marine ecosystems and global protein sources7.

Marine Food Webs

Ocean acidification affects various marine taxa, including reef-building corals, crustose coralline algae, and pteropods. These organisms play crucial roles in marine food webs, and their decline could propagate through multiple trophic levels, leading to unpredictable changes in species distributions and abundances2.

Chemical Communication

Marine animals rely on chemical cues for various behaviors, such as predator detection and reproduction. Research shows that ocean acidification can alter the structure and function of peptide signaling molecules, impairing these chemically mediated behaviors and interactions5.

Ecosystem-Level Changes

Studies conducted at volcanic CO2 vent sites, which simulate future ocean acidification conditions, reveal significant shifts in benthic ecosystems. Typical rocky shore communities with abundant calcareous organisms are replaced by communities lacking scleractinian corals and with reduced sea urchin and coralline algal abundance. These changes suggest that ocean acidification may benefit invasive non-native algal species, further altering ecosystem dynamics4.

Future Outlook

The current rate of ocean acidification is unprecedented, and its long-term impacts on marine ecosystems are still not fully understood. However, the evidence suggests that continued CO2 emissions will lead to more acidic oceans, with significant consequences for marine biodiversity and ecosystem services. Political will and large-scale investment in clean-energy technologies are essential to mitigate the most damaging effects of human-induced climate change, including ocean acidification2 6.

Will the oceans become acidic in the future?

Ben McNeil has answered Extremely Unlikely

An expert from UNSW Sydney in Oceanography, Climatology, Marine Science

Acidity is measured by the pH of a substance, which is defined by the hydrogen ion concentration (pH = -log[H+]). pH values above 7 are commonly referred to as “basic” (or “alkaline”) and pH lower than 7 as ‘acidic’. Today the surface oceans average pH is 8.1, making them alkaline. But carbon dioxide (CO2) when dissolved in water, increases the H+ concentration, thereby lowering the pH. As the oceans absorb billions of additional tonnes of CO2 produced from fossil-fuel pollution, the pH of the surface ocean has decreased by about 0.1 over the past century and will continue into the future – but the lowest potential pH projections into the future will be ~7.6-7.7. So the oceans are not likely to become ‘acidic’ over the coming centuries. However, as pH is measured on the logarithmic scale (see above equation), small changes in pH invoke large changes in seawater ‘acidity’. In our body even slight changes (~0.1) to our blood pH can cause serious health problems. For the oceans, these changes (0.1-0.4) in pH are likely to cause problems for some marine organisms and coral reefs, however the impact is still unclear based on species dependent responses. Here is a great primer on ocean pH (http://www.pmel.noaa.gov/co2/story/A+primer+on+pH)

Will the oceans become acidic in the future?

Robert Key has answered Extremely Unlikely

An expert from Princeton University in Oceanography, Palaeoclimatology, Climatology, Geochemistry

The difficulty with this question boils down to vocabulary. That is, it is highly unlikely that the ocean will become an acid (while humans still exist), but it will continue to become more acidic yearly. Whenever I try to explain this I start with a temperature comparison. If the temperature is 35C and then moves to 34C then it is correct to say that it has gotten colder, but no one would say that it is cold. Obviously, you would use warmer and hot instead. This provides a good analog to the ocean becoming more/less acid/acidic (or basic) and acid/base and allows simplification of the conversation to a level than anyone can understand based solely on personal experience.

Will the oceans become acidic in the future?

Robert Letscher has answered Unlikely

An expert from University of California, Irvine in Geochemistry, Oceanography

As has been pointed out by others in their responses, the oceans are definitely ‘acidifying’ currently and will continue to do so into the future for decades to centuries, even if human co2 emissions to the atmosphere cease. However, this acidification will not push the ocean pH below a value of 7 which is needed for a solution to be classified as ‘acidic’.

Will the oceans become acidic in the future?

Katsumi Matsumoto has answered Near Certain

An expert from University of Minnesota in Oceanography, Palaeoclimatology, Geochemistry

CO2 combined with water becomes an acid, carbonic acid. So long as CO2 will continue to be emitted, the oceans will become more acidic as they uptake CO2 via naturally occurring air-sea gas exchange.

Will the oceans become acidic in the future?

Clifford Goudey has answered Likely

An expert from Massachusetts Institute of Technology in Mechanical Engineering, Renewable Energy, Marine Science

Ocean acidification is happening now due to the increased uptake by the oceans of CO2 from the atmosphere. So as long as we keep atmospheric CO2 levels abnormally high from fossil fuel emissions, the oceans will continue to acidify. A conversion to renewable energy sources will reduce CO2 emissions and eventually our air and oceans will return to normal.

Will the oceans become acidic in the future?

Steven Campana has answered Near Certain

An expert from University of Iceland in Oceanography, Fisheries Sciences, Marine Ecology

The large-scale addition of CO2 to the atmosphere is now being transferred in part to the ocean, where it contributes to ocean acidification. So acidification will happen; it is a predictable chemical response. But it’s important to keep scale in mind. The amount of acidification will be undetectable to the average person; it is not as if the ocean is going to turn into a churning vat of acid. However, it will become acidic enough to disrupt the calcification of crustaceans and shellfish. And that by itself could cause huge problems in the marine ecosystem.

Will the oceans become acidic in the future?

Douglas Fenner has answered Uncertain

An expert from National Oceanic and Atmospheric Administration in Marine Biology

The problem here is the word “acidic.” Taken literally, that means “a pH below 7.” 7 is the pH of water, pure water with no CO2 in it. Using that meaning of the word, the oceans will NOT become acidic in the future. They are at about a pH of 8 now and will NOT get to below 7.

If the question were “is acidification happening in the ocean?” the answer is “YES.” “Acidification means a reduction in pH. Not reduction to below 7, but any reduction. Another term that would mean the same thing would be something like “debasification” or “dealkilination.” But those terms are not commonly used. So acidification is talking about the direction of change, but not specifying how much change, while “acidic” is saying what it will change to, “less than pH 7.”

Ocean waters are heavily “buffered” which means that because of chemicals already in them, adding an acid or base will not change the pH as much as if those chemicals were not present.

Acidification has already been happening, it happens because CO2 emitted by people burning things (and by producing cement) emitts CO2 into the atmosphere. CO2 readily dissolves in water, especially under pressure. When you open a container of soda pop, the “fizz” bubbles are CO2. You can get huge amounts to dissolve under pressure, release the pressure and it comes out. When it is dissolved in water, it reacts to form a weak acid, “carbonic acid.” That in turn reacts with several chemicals, which uses much but not all of it up. So CO2 from humans is reducing the ocean’s pH, but it will never make it have a pH below 7.