Report finds CO2 causing rapid ocean acidification

WASHINGTON, December 3, 2013—A report released in November concludes that the world’s oceans are acidifying at an “unprecedented rate.” Authored by researchers at the 2012 Third Symposium on the Ocean in a High CO2 World, the report warns that oceans have become 26% more acidic since the beginning of the Industrial Revolution and continue to do so.

Since the start of the Industrial Revolution, the world’s oceans have absorbed about a quarter of all CO2 emissions released by humans, according to the report.

When CO2 dissolves into the ocean, it creates carbonic acid. Carbonic acid leads to higher water acidity, especially near the surface. As levels of carbon dioxide (CO2) in the atmosphere rise due to human activity like burning fossil fuels, acidity levels in the oceans also rise.

“As ocean acidity increases, its capacity to absorb CO2 from the atmosphere decreases. This decreases the ocean’s role in moderating climate change,” write the authors of the report.

With the collaboration of 540 experts from 37 countries, the Symposium report warns that increasing ocean acidification is changing ecosystems and marine biodiversity, with the potential to affect food security and regional economies.

“Reducing CO2 emissions is the only way to minimize long-term, large scale risks,” warn study authors.

According to the report, species-specific observation both in the field and in laboratories show that acidification of ocean water has varying effects on different organisms “from the poles to the tropics.”

Acidification of the ocean can reduce an organism’s ability to sustain its shell or skeleton. It can also reduce the growth, survival, abundance, and larval development of a number of other species. Coral, mollusks, and shellfish are extremely vulnerable to carbonic acid in ocean water. According to National Geographic, carbonic acid has also been shown to cause reproductive disorders in some fish species.

On the other hand, increased acidification is well tolerated by other species that may thrive, like some sea grasses.

The effects of acidification will be felt in all of the world’s oceans within a few decades; scientists predict that within that time, the water in polar oceans will become too corrosive for the shells of certain organisms and the chemistry in the tropical ocean will slow down or even stop reef growth in some places.

The devastating effect of acidifying oceans will also be felt economically. The report predicts that if the oceans continue to acidify at the present rate, it will have a noticeable impact on food webs, ocean biodiversity, and the global fishing and shellfish industry. The U.S. shellfish industry alone could an estimated $130 billion yearly, according to the report’s authors, should current CO2 emissions remain the same.

Researchers note that the world’s poor, those located on coastlines, and those dependent on fishing are in an especially vulnerable position, as acidification endangers the fishing industry, and the destruction of coral reefs can impact tourism and reduce shoreline protection.

The report’s authors predict that if CO2 emissions continue at present levels, by 2100 the oceans will be 170 percent more acidic than before the start of the Industrial Revolution. Even if all human CO2 emissions were to stop immediately, according to the researchers, oceans and marine ecosystems would require decades to repair from the damage already done.

The report warns, however, that even though changes are expected in marine biodiversity and ecosystems in the next few decades, it is impossible to make reliable, quantitative predictions about the effects of rising CO2 levels on the world’s oceans. The report also notes that oceans face a variety of challenges not limited to acidification, including warming water temperatures, deoxygenation, pollution and overfishing, that all contribute to destruction of ecosystems and biodiversity.

“What I’m hoping is that people realize that CO2 is not just a question of global warming. That we are acidifying the ocean at a rate that has been unprecedented — for millions and millions of years,” said one of the report’s authors, Daniela Schmidt from the University of Bristol, to CNN.  “The more CO2 emissions, the more acidification. The ocean is in direct interchange with the atmosphere.”

The Scientific Committee on Oceanic Research, the Intergovernmental Oceanographic Commission of UNESCO, and the International Geosphere-Biosphere Programme sponsored the 2012 Symposium. The report was presented on November 18 during the U.N. Conference of the Parties climate change meeting in Warsaw, Poland.

Laura Sesana, The Washington Times, 3 December 2013. Article.

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