by According to the National Oceanic and Atmospheric Administration the warming of the oceans is causing massive bleaching events in coral reefs around the globe.
NOAA announced Monday that the “4th global coral bleaching event” was underway and that bleaching had been documented over the past 14 months in every major ocean basin, including off Florida in the United States, Australia’s Great Barrier Reef and in the South. the Pacific Ocean.
“As the world’s oceans continue to warm, coral bleaching is becoming more frequent and more severe,” Derek Manzello, a coral reef ecologist who coordinates NOAA’s Coral Reef Watch Program, said in a news release. “When these events are severe or long enough, they can cause coral mortality, which hurts the people who depend on coral reefs for their livelihoods.”
Sea surface temperatures have set daily records for more than a year, prompting concern among scientists trying to figure out how the oceans got so warm, so quickly. Warming from climate change and cycles of natural variability, such as El Niño, have played a significant role.
The health of corals is intertwined with ocean temperature because the invertebrates are extremely sensitive to heat stress. When corals are stressed, they turn white as they release symbiotic algae that live in their tissues. Bleaching is a sign that coral health is at risk.
“When a coral bleaches, it doesn’t mean it’s dead. It means it’s weak and in danger of dying if conditions don’t improve,” said Ana Palacio, an assistant scientist at the Cooperative for Marine and Atmospheric Studies, a research institute based at the University of Miami in partnership with NOAA. .
Corals are vital ecosystems that support a wide variety of fish and aquatic species, helping to sustain coastal communities and attract tourists. The economic value of reefs is estimated at $2.7 trillion per year, according to a 2020 report from the Global Coral Reef Monitoring Network.
“They protect our coast. They provide protection from storms and hurricanes. They are of great value to our economy and to our safety,” said Palacio.
Coral ecosystems are among the ecosystems that scientists think are most at risk from global warming. In 2018, the United Nations Intergovernmental Panel on Climate Change estimated that 70% to 90% of the world’s coral reefs would disappear if average global temperatures crossed a threshold of 1.5 degrees Celsius above the pre-industrial average.
Last year was the hottest on record in the world. Global average temperatures were approaching that threshold for the first time, although scientists believe El Niño increased temperatures and the year 2023 was an anomaly.
In Florida, as sea surface temperatures rose, bleaching began early in the season, experts said.
“Normally, bleaching will be observed in the Northern Hemisphere around August and September. We started observing bleaching last July,” said Phanor Montoya-Maya, a marine biologist with the Coral Restoration Foundation, an organization that collects, restores and repopulates corals.
Palacio said the region has seen widespread mortality of elkhorn and staghorn corals, two species that have been the focus of restoration efforts.
“In some places, about 20% of those populations survived,” Palacio said of restored corals. “We’re focusing our hopes on why those corals survived and what they can tell us about resistance and how corals can be more resilient.”
The last global coral bleaching event occurred in 2014 and lasted until 2017. More than 56% of global reef areas experienced temperatures that could cause bleaching during that time period.
In an email Monday, Manzello said 54% of the world’s coral reef areas had experienced bleaching-level heat stress in the past year and that the event was on track to be the worst bleaching event in history.
“The percentage of reef areas experiencing heat stress at predicted levels is increasing by about 1% per week,” Manzello said. “This event will likely exceed the previous peak.”
Montoya-Maya said a bleaching alert is already in place in Florida, even earlier than last year. He said the Coral Restoration Foundation was preparing for a busy summer responding to another bleaching event.
The natural El Niño pattern has begun to dissipate and NOAA’s Climate Prediction Center estimates a 60% chance of La Niña developing this summer, which could help cool Atlantic waters and allow some corals to recover, at least temporarily.
“This is heartbreaking and will damage many reefs around the world,” Palacio said. “Hopefully this bleaching event will create some traction and people will start to care more and pay attention to what’s happening with the climate.”
This article was originally published on NBCNews.com
