Hot and sour might be a delicious combination if you’re ordering soup in a Vietnamese restaurant, but when it comes to the world’s oceans, hot and sour is a deadly and destructive duo.
According to research just released by a panel of over 500 of the world’s leading experts on ocean acidification, increased levels of carbon dioxide in the atmosphere are acidifying the oceans at an “unprecedented rate, faster than at any time in the last 300 million years. Since the start of the industrial revolution, oceans have become 26% more acidic.
By 2100, ocean acidification is predicted to increase by 170 percent if current rates of greenhouse gas emissions continue. More acidic water will make the oceans unlivable for about 30 percent of ocean species. About one quarter of annual CO2 emissions from human activities currently end up in the ocean, or about 24 million tons of CO2 every day.
Some of the species most at risk are mollusks like oysters and clams, and corals, but any species that needs a hard shell to survive may be affected. Oyster farmers in the Northwest are already seeing the impact. The global cost of the decline in mollusks could be $130 billion by 2100.
Coral reefs are already imperiled by warming oceans which cause coral bleaching. But ocean acidification alone is likely to cause reef building to cease by the end of the 21st century on the current CO2 emissions trajectory. All the fish that depend on corals for habitat will also be indirectly affected by ocean acidification.
Other commercially important species like crab and lobster have not been shown to be adversely affected by more acidic oceans, but rising water temperatures do make lobsters extremely vulnerable to shell disease.
“People who rely on the ocean’s ecosystem services are especially vulnerable and may need to adapt or cope with ocean acidification impacts within decades,” the report says. “Tropical coral reef loss will affect tourism, food security and shoreline protection for many of the world’s poorest people.”
The effects of the unprecedentedly sour oceans are being felt the most in the Arctic and Antarctic, because frigid waters can hold more CO2 and thus cause more rapid acidification. Within the next six years, ten percent of the Arctic will be a no go for organisms that have calcium carbonate shells, and by the turn of the century, all of the Arctic will be lost habitat for these species. This change of course impacts not only shelled creatures, but all the fish, birds and marine mammals which depend on them for food.
And there’s one more catch to keep in mind — as ocean acidity increases, the oceans’ capacity to absorb CO2 from the atmosphere decreases, which means that the enormous carbon sink that has helped to moderate the warming climate thus far will become less and less effective.
The review of the state of the science will be formally presented at the U.N. Conference of the Parties climate change meeting in Warsaw, Poland, on November 18.