FACT BRIEF

Is the ocean acidifying?

Tuesday, June 4, 2024

By John Mason

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YES

Acidification of oceans simply means a reduction in their pH outside of normal values.

The pH scale measures acidity and alkalinity of water-based solutions. It runs from 0 (highly acidic) through 7 (neutral) to 14 (highly alkaline). Any reduction in pH value, in the direction of 0, is acidification. The oceans acidify whenever they become less alkaline, regardless of whether their pH declines below 7.

A good analogy for acidification can be found with the way we talk about temperatures. If the pH of a solution shifts from 8.1 to 7.9, that is acidification, even though the solution remains slightly alkaline. In the same way, if the temperature rises from -40°C to -15°C, it has definitely warmed up, even though it's still freezing cold.

Since the Industrial Revolution, ocean pH has declined from 8.2 to 8.1 — a 30% increase in acidity.

See a full discussion of this at Skeptical Science

This fact brief is responsive to conversations such as this one.

Sources

Smithsonian Ocean Ocean Acidification

Encyclopædia Britannica PH | Definition, Uses, & Facts

National Oceanic and Atmospheric Administration What is Ocean Acidification?

European Environment Agency Ocean acidification

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Skeptical Science is a non-profit science education organization. Our goal is to remove a roadblock to climate action by building public resilience against climate misinformation. We achieve this by publishing debunking of climate myths as well as providing resources for educators, communicators, scientists, and the general public. Skeptical Science was founded and is led by John Cook, a Senior Research Fellow with the Melbourne Centre for Behaviour Change at the University of Melbourne.

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