Ocean Acidification

Climate change’s spike up in carbon dioxide means that oceans—which cover 71 percent of Earth’s surface—are going to become cesspools.

“I have to admit, we’re just scratching the surface here,” Ulf Riebesell told The Daily Beast recently. He’s talking about how only now, decades after climate change was recognized as an impending crisis, we’re figuring out how the extreme temperatures facing Earth will affect the water covering 71 percent of the planet.

Riebesell is the lead author of a landmark study involving more than 250 scientists, 580 peer-reviewed articles, 20 German research institutions, and 350 marine species, trying to understand how climate change will affect the world’s oceans. Eight diligent years and $25.5 million later, Riebesell’s team’s research was presented at the annual United Nations Climate Change Conference in Bonn, Germany, this week.

The findings: Our oceans are about to get extremely acidic (PDF).

Referred to by the scientific community as “the other carbon dioxide problem,” ocean acidification is the phenomenon of decreasing pH levels in ocean water. That’s in response to increasing carbon dioxide in seawater instead of in the atmosphere.

It might seem harmless, but the fact that carbon dioxide levels are about to spike up in the ocean has some potentially devastating, wide-ranging impacts on marine and human life. At risk is everything from global climate regulation to the availability of fish for human consumption.

“Personally, I’m very concerned that the future ocean will be less biodiverse,” Riebesell said. “There will be fewer species in the ocean. Many [ocean animals] living today will not be competitive under future conditions,” Riebesell said. In other words, even the slightest uptick in carbon dioxide could completely extinguish entire species of ocean animals.

Ocean acidification will inevitably play into coastal economies that rely on oceans as a food and monetary source. “If all of a sudden the ocean doesn’t provide as much, this will make a major difference,” Riebesell said.

The acidification of the world’s oceans did not happen overnight. Approximately 30 percent of greenhouse gases released by humans into the atmosphere since industrialization began have been absorbed by the waters that make up the majority of the planet’s constitution. It’s an inverse relationship: The more carbon dioxide humans release, the less the ocean absorbs.

Which might seem advantageous on the surface, Riebesell admitted. “The uptake of carbon dioxide is a great service to the climate system. It slows down global warming,” he said. “At the same time that the ocean takes up carbon dioxide, it loses its buffer capacity, and the end result is the more acidified it gets, the less carbon dioxide it can take up of what we emit into the atmosphere.” Riebesell added that decreasing carbon dioxide absorption from the atmosphere is factored into existing climate change models.

Currently, the increase in surface ocean water acidity also hovers around 30 percent. This number, however, can be expected to rise along with increasing greenhouse gas emissions.

“The equivalent of this is bubbles in your soda water,” Jeff Orlowski, director of the Emmy Award-winning 2012 documentary Chasing Ice, and the recently released Chasing Coral, said, as an illustration, adding that he didn’t think the carbonization would be visibly noticeable.

“Everything in the ocean is connected through the water, and we’re changing the chemistry of the water. So, picture our atmosphere changing in a significant way. … Imagine there was a 30 percent change in oxygen production, for example. That would systematically change all life on land,” Orlowski said.

Through chemical reactions, acidification increases hydrogen in the water, benefitting algae production. At the same time it reduces carbonate, negatively impacting coral, shellfish, snails, some phytoplankton (microscopic plants), and other calcifying organisms—which all rely on carbonate to produce their shells or skeletons.

This fundamental change in animal biology from ocean acidification is already happening. Riebesell said he started noticing that oyster larvae weren’t developing properly in Pacific Northwest hatcheries a few years ago. “The young larval and juvenile life stages are very sensitive to acidification. Basically, the larvae didn’t grow—a loss of hundreds of millions of U.S. dollars to oyster hatcheries,” he said.

The larvae of cod, a popular staple, is especially sensitive to acidification, leading to anticipated declines of up to 25 percent in stock. Some hatcheries increased their water’s pH, while others relocated, impacting local economies.

Changes in migratory patterns of fish can also be expected, Riebesell said, which could wreak havoc on local communities, as fish once available close to a coast, for example, head for the deep ocean.

The degradation of coral reefs, already severely challenged by warmer waters, leaves nearby coastal areas vulnerable to erosion and storm surge, while also reducing habitat for coral-dependent food species.

Still, small steps are helpful and might make a big impact. Riebesell and Orlowski urged world leaders to honor the Paris climate agreement (the U.S. has not signed on to it), and say that even figuring out ways to reduce your personal carbon footprint with lifestyle modifications can have wide impact.

But is it too late to completely reverse ocean acidification? Maybe, Orlowski said. “The ocean is not too big to fail,” he lamented.

Carah Wertheimer, The Daily Beast, 11 November 2017. Article.