Why is ocean acidification called the other co2 problem?

Ocean acidification is referred to as the "other CO2 problem" because it is a significant consequence of increased carbon dioxide (CO2) emissions, alongside climate change. When CO2 is absorbed by seawater, it reacts to form carbonic acid, lowering the ocean's pH and making it more acidic. This change can have detrimental effects on marine ecosystems, particularly on organisms like corals and shellfish that rely on calcium carbonate for their structures. While climate change focuses on global warming, ocean acidification poses a critical threat to ocean health and biodiversity.