Australia’s Great Barrier Reef is suffering its worst coral bleaching in recorded history with 93 percent of the World Heritage site affected, scientists said Wednesday, as they revealed the phenomenon is also hitting the other side of the country. A recent study of the Great Barrier Reef has shown that in the past 30,000 years the world’s largest reef system has suffered five death events.
The current damage is a harbinger of what climate change has in store for the Earth’s reef ecosystems in the future. “The replenishment ability of the reef has been diminished”, Terry Hughes, the study’s lead author and director of the Australian Research Council Center of Excellence for Coral Reef Studies at James Cook University in Queensland, said in an interview.
Coral bleaching is a phenomenon in which stressed corals expel algae and turn white, often as a result of warming ocean temperatures. Bleaching doesn’t kill corals immediately, and they can recover. Reefs can recover, but this recovery can take as long as a decade. Climate change will makes things worse. The exposure of the Great Barrier Reef to ocean acidification.
“Unfortunately, they might not have long. We just reached the end of a three-year long global bleaching event ” , said Mark Eakin, coordinator of the National Oceanic and Atmospheric Administration’s Coral Reef Watch and a chief science advisor for the Netflix movie.
Scientists have warned that the world must limit global warming to 1.5 degrees Celsius above pre-industrial levels if the planet hopes to stave off the worst effects of climate change, a prospect that looks increasingly unlikely.
Coral reefs are important ecosystems of ecological, economic and cultural value yet they are in decline worldwide due to human activities. Researchers say bleaching happens when corals’ environment changes suddenly. If not given time to recover, bleached corals can perish. Nearly half of the coral-around 1 billion animals-died in the past two years, Hughes tells The Washington Post. Bleaching is caused by anomalously warm water, which prompts coral polyps to eject their symbiotic algae.
Climate change is warming the world’s oceans, creating more mass bleaching events.
Coral researcher Erinn Muller, Ph. D. says “coral reefs don’t easily bounce back from loss events like disease outbreaks or bleaching from hot water. Transitioning from 50 percent of the reef being covered by living corals, now we’re down to about five percent coral cover”.
Coral bleaching is a phenomenon in which stressed corals expel algae and turn white, often as a result of warming ocean temperatures. Bleaching doesn’t kill corals immediately, and they can recover. Reefs can recover, but this recovery can take as long as a decade. Climate change will make things worse. The exposure of the Great Barrier Reef to ocean acidification.
And check out the NOAA’s Coral Reef Watch. Last spring, marine biologists reported that we ‘re currently in the midst of one of the largest coral die-offs they’d ever seen, and the third global bleaching event on record. Though many corals resemble cacti or flowers, they ‘re animals, not plants. This leads to the condition marine scientists call “bleaching”.
As global temperatures continue to rise, fueling ever more powerful El Niño events, coral are being left with little time to recover before they get hit by another hot spell. Global warming has disappeared. Australian scientists are warning that warm waters have caused severe bleaching of the Great Barrier Reef’s northern section.
This dramatic collapse of once colorful and vibrant marine ecosystems has accelerated in recent years, due to the relentlessly warming ocean waters. Higher than usual water temperatures led to Hawaii’s coral reefs “bleaching”. When sea surface temperatures rise, corals expel the colourful algae. It’s estimated that some reefs around Hawaii’s coast experienced a 90 percent mortality rate. The too-warm temperatures prompted the coral to expel the colorful algae living on them, turning them white.
The situation is so bad that the US National Oceanic and Atmospheric Administration declared a global coral bleaching event last week-only the third ever recorded. As global warming continues, it is likely that these events will become more frequent.
A similar process is happening to some coral species. The acidity of the ocean’s surface has increased due to increased atmospheric CO2. At the PETM 56 million years ago, very high levels of CO2 persisted for several thousand years. For many reefs across the Caribbean and Indian Ocean regions, where the study focused, rates of growth are slowing due to coral reef degradation. Some 1,500 fish species call it home.
Scientists there have coral records going back 400 years. A very old Porites colony on Jarvis has seen many El Nino’s. In fact, new research has revealed that they may very well disappear unless a significant amount of cuts are made in greenhouse gas emissions.
Prolonged periods of extreme heat in the oceans can damage kelp forests and coral reefs, and harm fish and other marine life. And not surprisingly, temperatures are rising globally. Yet the scale of this bleaching event has even the most sober and senior coral reef scientists worried. Unless humanity gets its act together, we can expect much worse to come.
The study says, by the year 2100, three out of four people on Earth could be subject to at least 20 days per year of heat and humidity associated with deadly heat waves, if greenhouse emissions continue to rise at their current rates. For heatwaves, our options are now between bad or terrible.
Many people around the world are already paying the greatest price of heatwaves. So, it would be just a big jerk to the global climate. The latest report from the Climate Council has found coral bleaching events are increasingly common and will continue to be unless the effects of climate change can be slowed or reversed. Pollution data used in our study show that water quality in 2016 may have been better than in earlier bleaching years.
Among the changes that can be expected are rising sea levels and decreases in rainfall that last for centuries. Some 38% of coral reefs will be bleached this year, says NOAA.
Image Credits: PETER MUMBY
