Upwelling regions intensify ocean acidification beyond what atmospheric CO2 increases would alone, threatening coastal ecosystems and industries.

Historic coral boron isotope records were used to reconstruct 20th-century coastal acidity and, with regional ocean modeling, project 21st-century changes.

The research emphasizes understanding regional ocean processes and supports ongoing climate mitigation and adaptation efforts, including renewable energy and electrification to protect ocean health.

A Nature Communications study of the California Current shows deeper, naturally acidic waters rise to the surface, releasing CO2 from microbial decomposition and amplifying surface acidity when they mix with atmospheric CO2.

Findings indicate upwelling zones experience faster acidification rates due to the pre-existing acidity of upwelled water, intensifying local impacts.

Implications extend to major global upwelling systems like Humboldt, Benguela, and Canary, which may face similar accelerated acidification as CO2 levels rise.