The rising concentration of carbon dioxide (CO2) in the atmosphere is a major driver of ocean acidification. The ocean absorbs about a quarter of the CO2 released through human activities like burning fossil fuels. As CO2 dissolves in seawater, it creates carbonic acid, which makes the ocean more acidic.
Here's a simplified breakdown of the process:
CO2 dissolves in seawater
CO2 + H2O -> H2CO3 (carbonic acid)
H2CO3 dissociates into H+ (hydrogen ions) and HCO3- (bicarbonate ions)
The increased concentration of H+ ions lowers the pH of the ocean, making it more acidic. This can have negative consequences for marine life, especially organisms that build shells and skeletons from calcium carbonate.