The ocean is changing, and not in a good way. Over the past 200 years, human activities like burning fossil fuels and deforestation have significantly increased carbon dioxide (CO₂) levels in the atmosphere. The ocean absorbs about 30% of this CO₂, triggering a chemical reaction that lowers the pH of the water.

Since then, the pH of surface ocean waters has dropped by 0.1 units—which may sound small, but because the pH scale is logarithmic, it actually means the ocean is about 30% more acidic than before.

According to NOAA, this increasing acidity is already harming marine life, and the problem is only getting worse.

When CO₂ mixes with seawater, it creates carbonic acid, which lowers the pH of the ocean. Think of it like adding lemon juice to water—it becomes more acidic. This increase in acidity causes a big problem for shellfish, corals, and other sea creatures that rely on carbonate to build their shells and skeletons. But with more acid in the water, there’s less carbonate available, making it harder for these creatures to grow and survive.

Tiny sea snails called pteropods, also known as “sea butterflies,” are among the first to feel the impact. NOAA research shows that when these creatures were placed in more acidic water, their shells began dissolving in just 45 days. This is a big deal because pteropods are food for many sea creatures, including krill, fish, and even whales. If they disappear, entire food chains could collapse. Acidification also affects fish—clownfish struggle to sense predators, making them more vulnerable.

Ocean acidification isn’t just bad for marine life—it’s bad for us too. Billions of people rely on seafood for food, and many jobs depend on fisheries that could shrink if shellfish populations decline. Coral reefs, which support marine life and protect coasts from storms, are also in trouble. If we keep polluting at the current rate, the ocean’s pH could drop to 7.8 by 2100, a level not seen in millions of years—a time when mass extinctions were happening.

The good news? We can still slow this down. The best way to stop ocean acidification is to reduce CO₂ emissions by switching to clean energy sources like wind and solar power. Scientists are also exploring solutions like growing more seagrass and seaweed, which absorb CO₂ and help balance ocean chemistry. But the biggest impact comes from cutting down pollution and protecting marine ecosystems.

The ocean has been absorbing our pollution for centuries, but it can’t keep up forever. If we act now, we can protect marine life, coastal communities, and the future of our planet. The time to make a change is now.

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