Ocean Warming and Acidification Accelerate Global Climate Impacts
Rising sea temperatures and altering ocean chemistry threaten coastal communities, marine ecosystems and global food security.
- By Jesse Jacobs
- July 27, 2026
Global ocean temperatures and sea levels are rising at accelerated rates, signaling deep structural changes in the planet's climate system driven by human-caused greenhouse gas emissions.
According to analysis by World Resources Institute expert Tom Pickerell, the ocean absorbs approximately 91% of the excess heat trapped by greenhouse gases. This energy imbalance has caused sea surface temperatures to reach record highs, while the rate of ocean warming between 2005 and 2025 more than doubled compared to the period between 1960 and 2005.
The heat intake has triggered rapid melting of polar sea ice and thermal expansion of seawater. By late 2025, global average sea levels were about 11 centimeters higher than in 1993, with the rate of annual increase nearly doubling over the past decade.
Beyond thermal changes, the ocean absorbs about 25% of human-generated carbon dioxide emissions. This process has increased average surface ocean acidity by roughly 30% since the preindustrial era. Higher acidity lowers the availability of carbonate ions, threatening shell-forming organisms, coral reefs and commercial fisheries.
The physical and chemical changes in seawater are already disrupting coastal livelihoods. Rising sea levels are pushing saltwater into agricultural lands in low-lying countries such as The Gambia, while island nations like Tuvalu face severe land loss and forced migration.
While deep-ocean warming and interior acidification are largely irreversible on human timescales, environmental experts emphasize that expanding coastal adaptation, protecting natural buffers like mangroves and using advanced ocean-observation systems can significantly mitigate near-term risks.
About the Author
Jesse Jacobs is Assistant Editor of EPOnline.com.