Scientists: Corals could disappear from Japan if CO2 continues to rise

January 10, 2013

By TOMOYUKI YAMAMOTO/ Staff Writer

TSUKUBA, Ibaraki Prefecture—Corals could become extinct in the waters around Japan within 60 years if carbon dioxide emissions continue to rise at their current rates, the National Institute for Environment Studies and Hokkaido University said Jan. 9.

Researchers from the two institutes and Swiss scientists used supercomputers to model how Japan's marine habitats might change under a global-warming scenario of the Intergovernmental Panel on Climate Change.

The calculations were based on a "business as usual" model of CO2 emissions, which says that airborne CO2 concentrations will more than double from current levels by 2100. CO2 is believed to induce global warming.

The results showed that areas of high temperature, where coral is prone to bleaching and dying, would expand to waters off southern Kyushu and all parts of Okinawa Prefecture. Furthermore, high airborne CO2 dissolving in seawater would accelerate ocean acidification, which itself would make broad areas around Japan uninhabitable for corals because high acidity prevents corals from forming skeletons.

"The impact of acidification is larger than we expected," said Hiroya Yamano, a senior researcher at the National Institute for Environment Studies. "Reducing CO2 emissions is the only way to preserve corals."

The scientists estimated that by the 2060s, corals would only be able to grow in locations off Kyushu and Shikoku—and that they, too, would become uninhabitable a decade later.

The research results were published in December in Biogeosciences, a science journal.

By TOMOYUKI YAMAMOTO/ Staff Writer
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Corals off Ishigakijima island, Okinawa Prefecture (Provided by the National Institute for Environment Studies)

Corals off Ishigakijima island, Okinawa Prefecture (Provided by the National Institute for Environment Studies)

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  • Corals off Ishigakijima island, Okinawa Prefecture (Provided by the National Institute for Environment Studies)

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