A Norwegin coral reef with gorgonian and stony corals in Norway.
CREDIT: AP Photo/GEOMAR, Karen Hissmann
The growing acidity of the world’s oceans could cost the global economy $1 trillion by 2100 if humans don’t stop putting so much carbon dioxide into the atmosphere, according to an extensive report compiled by 30 experts worldwide and released Wednesday by the U.N. Convention on Biological Diversity.
Oceans have absorbed so much carbon dioxide emitted from power plants, deforestation, manufacturing, and driving, that their acid levels have increased by a staggering 26 percent over the last 200 years, the report said. The disruption of the ocean’s natural pH levels are directly impacting the health of marine life and ecosystems and scientists emphasize that if these trends continue unchecked, it could be both horribly detrimental for the world economy and largely irreversible for thousands of years.
“The oceans are facing major threats due to rising levels of carbon dioxide in the atmosphere,” said Braulio Terreira de Souza Dias, the Convention’s executive director, in a statement accompanying the report. “In addition to driving global climate change, increasing concentrations of carbon dioxide affect ocean chemistry, impacting marine ecosystems and compromises the health of the oceans and their ability to provide important services to the global community.”
Wednesday’s report is intended to be the most up-to-date compilation of what we currently know about ocean acidification — one of the biggest and least talked about effects of global warming — and what we know so far about its effects. It draws on hundreds of peer-reviewed papers published in the last few years to provide a comprehensive guide. Here are some of its most important takeaways.
More than a quarter of all CO2 emitted is absorbed by the ocean
CREDIT: National Resource Council
Not all greenhouse gas emissions from power plants and other sources end up in the atmosphere. According to the report, more than 25 percent of all carbon emissions are absorbed into the ocean. When the carbon enters the ocean, it dissolves, forming carbonic acid. The carbonic acid then dissociates, and forms bicarbonate ions and hydrogen ions. As the hydrogen ions increase, so does the ocean’s acidity.
The acidity that results does not mean that the ocean is actually acid, or falling below a pH level of 7.0. The term “acidification” refers only to the process of the oceans becoming less alkaline than they were previously. It is possible, however, that oceans could eventually fall into the acid category if emissions keep rising over the next 100 years.
An acidic ocean hurts marine life, and therefore hurts the economy
CREDIT: CDB.int
From left the right, this graphic shows the direct impacts of putting CO2 into the ocean, and how those impacts effect ecosystems, food security, and coastal protection, among other things.
Increased ocean acidity impacts the ocean in a number of ways. Directly, it can make it harder for coral and some plankton to produce their skeletons and shells, and increase the risk of those shells dissolving. Acidification can also change the behavior of marine fish and some invertebrates, making them more susceptible to predators. The U.N. study cited reef fish larvae as an example, observing that fish exposed to elevated CO2 lost their abilities to distinguish between different habitat types, to distinguish between kin and non-kin, and to smell predators. Fish, the report said, become “no longer able to learn.”
In all, acidification harms ocean ecosystems, which is bad for humans because ocean ecosystems “help create human well-being and economic wealth,” the report says. Specifically, ocean ecosystems support a number of industries: commercial fishing, shellfishing, tourism, leisure and recreation. Reduced coral health can impact their natural defense of erosion, making it more costly to maintain coastlines.
The U.N. report admits that more research needs to be done on the extent of harm that will be done to these industries because of acidification, and the uncertainty makes it difficult to estimate the economic impacts. At least one study, though, determined that the global economy would lose up to $1 trillion in services like coastline maintenance by 2011, just because of impacts on coral reefs. Those estimated losses don’t include effects on tourism or other industries.