The economic impacts of ocean acidification are already being felt
Rising acidity levels in the oceans have posed a serious threat to shellfish, particularly oysters.
CREDIT: AP Photo/Ted S. Warren
The U.N. report cited “strong evidence” that acidification is already negatively impacting shellfisheries off the northwest coast of the U.S., partially because the pH of the water there is already so low. Oyster hatcheries in Oregon and Washington, the report said, have been suffering high death rates in larvae — up to 80 percent — since 2006. The pH of the hatchery’s water are “major factors” affecting that death rate, the study said.
The problem at one point threatened the viability of that industry, which the report says has a total economic value of about $280 million every year.
Fortunately, those businesses have been able to recover their operations for now. “The oyster hatcheries have now adapted their working practices so that they avoid using very low pH seawater, either by re-circulating their seawater or treating their water during upwelling events,” the report said. “With these new practices, the north-west coast oyster hatcheries are producing near to full capacity again.”
If we don’t stop acidification soon, fixing it could take thousands of years
This graphic shows how the pH level of the ocean would change in the “business as usual” scenario predicted by the IPCC.
CREDIT: CBD.int
One of the most jarring aspects of the U.N. report is its observations of historical evidence to see how long it would take to restore oceans to normal after an acidification period. The Paleocene-Eocene Thermal Maximum (PETM), or about 56 million years ago, likely had carbon content closest to the content we have today, the report said.
It’s not a perfect analogy, the report says, as the carbon that was concentrated in the ocean 56 million years ago was naturally accumulated over thousands of years, not man-made over tens or hundreds of years like today. Back then, an estimated 2000-3000 petagrams of carbon was released into earth’s atmosphere over 10,000 years. Now, the IPCC predicts the world will release 5000 petagrams of carbon into the atmosphere over the next 500 years if we follow a “business as usual” scenario.
The geological record shows that it took approximately 100,000 years for the oceans to return to the pH level we now consider to be “normal” after the PETM. That leads scientists to believe that, absent some sort of remedy, it could take a similar amount of time for our ocean to return back to normal as well.
“We can see that ocean acidification is not a short-lived problem,” the report reads, “and [it] could take many thousands of years to return to pre-industrial levels even if carbon emissions are curbed.”