Purple coral off the coast of Maui, Hawaii. Photo by: Rhett A. Butler.
In an unprecedented show of concern, 2,600 (and rising) of the world’s top marine scientists have released a Consensus Statement on Climate Change and Coral Reefs that raises alarm bells about the state of the world’s reefs as they are pummeled by rising temperatures and ocean acidification, both caused by greenhouse gas emissions. The statement was released at the 12th International Coral Reef Symposium.
“Rising sea levels, more intense storms, changes in ocean chemistry due to air and water pollution—all these stress coral reefs,” said chief organizer of the statement, Steve Palumbi with the Center for Ocean Solutions, in a press release. “At least 25 percent of the world’s coral reefs have been degraded. Because of the global origin of climate change, the only way to tackle this is through a worldwide effort.”
Higher temperatures in the ocean has resulted in unheard of coral bleaching events, whereby the coral loses its symbiotic zooxanthellae, which can severely weaken reefs and even lead to mass mortality. In addition, acidification of the oceans, which is caused by excessive carbon inputs into the ocean, decreases calcium carbonate; corals, as well as marine mollusks and even some plankton, depend on calcium carbonate to survive. A recent study found that ocean acidification is currently occurring at a rate not seen for 300 million years, a trend that could eventually lead not only to coral decline, but mass extinction throughout the oceans.
“The international Coral Reef Science Community calls on all governments to ensure the future of coral reefs, through global action to reduce the emissions of carbon dioxide and other greenhouse gases, and via improved local protection of coral reefs,” the statement reads. While governments have been negotiating climate change agreements for decades, global greenhouse gas emissions continue to rise. A lack of concerted action means that global temperatures are currently on track to hit 6 degrees Celsius (11 degrees Fahrenheit) by 2100, according to the International Energy Agency (IEA); this would essentially lead to a climate catastrophe with temperatures rising higher than they have been in 50 million years.
Terry Hughes, Director of the ARC Centre of Excellence for Coral Reef Studies, echoed warnings by the IEA: “There is a window of opportunity for the world to act on climate change—but it is closing rapidly.”
The statement also makes note that coral reefs are being injured by other human impacts in addition to climate change, such as overfishing, habitat destruction, and pollution.
“The world, its coral reefs and the millions of people that depend upon them need more bold action,” the head of the U.S. National Oceanic and Atmospheric Administration, Jane Lubchenco, speaking at the conference told attendees:
In uncharacteristically strong words about climate change from the Obama Administration, Lubchenco noted that within 50 years 95 percent of the world’s coral reefs could suffer bleaching events. In addition, ocean acidification—which she called “climate change’s equally evil twin”—posed a “a serious threat to most corals.”
Researchers have estimated that coral reefs provide ecosystem services worldwide to the tune of $170 to $375 billion. Many communities depend on coral reefs for food security, storm and erosion buffers, and tourism. They are also the ocean’s most biodiverse ecosystem, harboring around a quarter of the world’s marine species.
(03/05/2012) Human emissions of carbon dioxide may be acidifying the oceans at a rate not seen in 300 million years, according to new research published in Science. The ground-breaking study, which measures for the first time the rate of current acidification compared with other occurrences going back 300 million years, warns that carbon emissions, unchecked, will likely lead to a mass extinction in the world’s oceans. Acidification particularly threatens species dependent on calcium carbonate (a chemical compound that drops as the ocean acidifies) such as coral reefs, marine mollusks, and even some plankton. As these species vanish, thousands of others that depend on them are likely to follow.
(01/24/2012) Emissions of carbon over the last two centuries have raised the acidity of the oceans to the highest levels in 21,000 years and likely beyond, according to a new study in Nature Climate Change. The change threatens a number of marine species, including coral reefs and molluscs.
(06/14/2012) In an announcement to coincide with the beginnings of the UN’s Rio+20 Summit on Sustainable Development, Australia has announced ambitious plans to protect 3.1 million square kilometers (1.19 million square miles) of its ocean, including the Coral Sea. If enacted, the proposition will increase Australia’s marine protected areas from 27 to 60, covering about 40 percent of Australia’s waters.
(06/11/2012) The first time I ever saw a giant clam was at a ride in Walt Disney World’s Magic Kingdom. My family and I piled into the Nautilus submersible at the 20,000 Leagues Under the Sea: Submarine Voyage and descended into the playtime depths. While we saw sea turtles, sharks, lobsters, mermaids, and even a sea monster, the creature that lingered in my mind most was the giant clam, raising and closing its pearly shell in the weedy abyss. Of course, none of these aquatic wonders were real—they were animatronics—but to a child with a vivid imagination they stirred within me the deep mystery of the boundless ocean, and none more so than that monstrous clam with its gaping maw.
(04/25/2012) Illegal fishermen have been utilizing homemade bombs to kill fish off the coast of Komodo Island, Indonesia, reports the Associated Press (AP); the bombs have not only injured fish populations in the protected area, but has also blasted biodiverse coral reefs popular with tourists. A scuba teacher told the AP that a section of Tatawa Besar coral reef, a popular diving spot, had been “blasted, ripped off, turned upside down.”
(04/18/2012) A new video by Google Earth and the World Resources Institute (WRI) highlights the world’s many endangered coral reefs. A part of the WRI’s Reefs at Risk program, the video highlights regional and global threats to the oceans’ most biodiverse ecosystem. According to the WRI, a stunning 75 percent of the world’s reefs are currently threatened.