Carbon emissions are bad for the atmosphere, but they aren’t good for the ocean either — and a new report says the forecast may be even worse that we thought.
The ocean is the world’s largest carbon sink, absorbing about a quarter of the carbon dioxide released into the atmosphere each year. But a new report from the World Meteorological Organisation says the ocean’s capacity to keep taking in carbon may be shrinking. And that could have devastating impacts.
The WMO reports that the ocean has already dropped to 70% of its pre-industrial ability to absorb CO2, and if conditions don’t change it could be as low as 20% by the end of the century. Carbon dioxide that goes into the ocean stays out of the atmosphere, an important role to slow against global warming — but as the oceans take in more CO2, the ecosystems within them face more problems.
When carbon dioxide enters the ocean, it undergoes a chemical reaction with the water, which causes the ocean’s pH to drop toward the acidic end of the pH spectrum. Small organisms, such as coral and shellfish, have been known to suffer under acidic conditions, and their demise could impact other animals all the way up the food chain.
The below graph shows the negative impacts of ocean acidification, with the bottom panel showing how four types of animals are adversely affected by increasing acidity. Not surprisingly, increases in acidity increase negative effects in all the surveyed creatures.
As you move right on each graph, the acidity goes up, as do the negative effects, seen in purple. Animals which use calcium carbonate, such as corals and mollusks, are at greater risk.
Several stations monitor ocean pH around the world, and their results show a concerning downward trend — acidification. This WMO chart shows results from a handful of stations. The numbers differ slightly among the datasets because of their local environments, but each one shows an overall decrease in pH from 1990 on — and no sign that the progress will be slowing any time soon.
Despite these stations’ efforts, the WMO reports that even more data collection is needed if we are to understand and effectively monitor trends in carbon uptake and ocean acidification. It’s a crucial step in the effort to save the planet’s most important carbon sink — and the thousands of organisms that rely on it for survival.
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