Ocean Coral’s White Skeletons Send a Stark Message

Environment Policy Brief #168 | By: Todd J. Broadman | May 30, 2024
Featured Photo: www.carbonbrief.org


Coral worldwide is in the midst of a fourth mass bleaching event according to the National Oceanic and Atmospheric Administration (NOAA). Huge stretches of coral reef have turned white or are losing color , primarily due to warm ocean temperatures. These bleaching events do not necessarily kill off the corals, yet mortality usually follows such events. Current average ocean temperatures, say most scientists, exceed the threshold for coral reef survival and their prognosis is that between 70% and 90% of reefs will die off within the next decade if they do not make a recovery.

In arriving at this conclusion the NOAA gathers satellite data which records ocean temperatures over a long period of time. Scientists also gather data directly through on the ground observation. The accumulated heat stress indicates an intensity of bleaching not seen before. So somber are their reports that there is jubilation when they find stretches of reef that have not been bleached.

“We have crossed the tipping point for coral reefs,” according to ecologist David Obura, with Coastal Oceans Research and Development.  “They’re going into a decline that we cannot stop, unless we really stop carbon dioxide emissions.” The beautiful coloration seen in coral is due to algae. Algae lives inside coral and has a symbiotic relationship with coral tissue. The bleaching or whiteness happens when algae leave coral due to stress. If the algae loss persists over a long period of time, the coral will then die.

While this process is unfolding, there is a U.S. federal agency focused on coral reefs: the United States Coral Reef Task Force (USCRTF). The USCRTF was established in 1998 by Executive Order with a mission to preserve and protect coral reef ecosystems. Historically, the USCRTF has helped build partnerships and strategies, yet has carried out minimal on-the-ground action to conserve coral reefs. Other federal agencies that partner with the USCRTF include: the U.S. Geological Survey (USGS), Federal Emergency Management Agency (FEMA), U.S. Army Corps of Engineers (USACE), National Oceanic and Atmospheric Administration (NOAA), and the University of California, Santa Cruz (UCSC). The USCRTF has gone so far as to have “approved a resolution recognizing coral reefs of U.S. states and territories as national, natural infrastructure.”  This resolution “encourages” the use of federal funding to help conserve and restore coral reefs. They aim to “fortify the nation’s commitment” to coral reefs. These faint intentions fall short of effective policy-making.

While coral reefs cover less than one percent of the ocean floor, they deliver vital benefits for marine ecosystems and economies. A full quarter of marine life depends upon coral reefs for shelter, food, and spawning. The Global Coral Reef Monitoring Network estimates that every year coral reefs provide about $2.7 trillion in goods and services, from tourism to coastal protection. Recreation generates about $36 billion from snorkeling and scuba diving tourism. Coral reefs are a natural protective barrier against storm surges and large waves.


In March of this year, global average sea surface temperature (SST) reached a record monthly high of 21.07C (69.93F), according to the EU Copernicus Climate Change Service. Neal Cantin, a coral biologist with the Australian Institute of Marine Sciences, outlines the stakes: “We’re certainly in a new regime. Corals clearly aren’t keeping up.” As a consequence, 75 percent of the Great Barrier Reef, an area the size of Italy, has experienced bleaching this year, the fifth bleaching event in the last 8 years. Since 1950 nearly 90 percent of the live corals in the Florida Keys have been lost. A 2005 bleaching event in the Caribbean around Antilles and Puerto Rico saw a loss of 50 percent. This alters the entire ecosystem of the surrounding oceans; like having “a rain forest without the rain forest trees.”

What we know is that the time gap between one bleaching event and the next is getting shorter. And those gaps are critical because they are a time window for the corals to recover. Corals need time – nine to twelve years – for the waters to cool so that the life-giving algae returns. More and more of them will not recover and left as “graveyards of calcium carbonate skeletons” which will erode and break apart.

Interventions such as breeding corals in labs will do little to stay the mass death of this species. Anticipating possible extinction, scientists are placing coral larvae into cryopreservation banks, as well as breeding corals with more resilient traits. As David Obura underscores, “When a 50- or 100-year-old coral dies, it takes at least that length of time to replace it. And we just don’t have that kind of time anymore.” As with other species, what has taken millennia of biology to develop is undone in a few generations of human environmental disregard. The spectacular beauty and place of coral is no match for an anthropocentric worldview with oil at its center.

Engagement Resources:
  • https://oceanservice.noaa.gov/  The National Ocean Service provides data, tools, and services that protect our ecosystems and enhance climate and economic resilience.
  • https://www.barrierreef.org/ collaborates and invests in innovative ideas and designs real-world, scalable conservation programs in Australia and the Pacific.
  • https://insideclimatenews.org/ provides essential reporting and analysis on climate change, energy and the environment, for the public and for decision makers.

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