The cause of the upcoming unprecedented coral bleaching has been identified

“Unprecedented mass coral bleaching” is expected in 2024, experts warn. Record land and sea temperatures caused by climate change are likely to cause “unprecedented mass coral bleaching and mortality” during 2024, according to a pioneering coral scientist.

The impact of climate change on coral reefs has reached “uncharted territory”, warns Australian professor Ove Hoeg-Guldberg from the University of Queensland, raising fears we could be at a “tipping point”.

The upper ocean is undergoing unprecedented changes in conditions, ecosystems and communities that can be traced back to the 1980s, when mass coral bleaching first began. In a paper published in the journal Science, US and Australian researchers say four decades of historical sea surface temperature data suggest this year’s extreme marine heat could be a harbinger of mass coral bleaching and die-offs in the Indo-Pacific region in 2024 -2025.

According to The Guardian, mass coral bleaching occurs when delicate corals are stressed by factors such as heat, causing them to lose their brown microbial algae, turning white. At low levels of stress, algae can return to the coral within a few months. But many areas of the Caribbean reefs have recently experienced historically high sea temperatures that began one or two months earlier and lasted longer than usual.

It’s important to note that 2023 is the first year of a potential pair of El Niño years where average global sea surface temperatures from February to July will be the warmest on record. Since 1997, each occurrence of these El Niño pairs has resulted in a global mass coral bleaching event.

Professor Hoeg-Guldberg, whose work has helped shape the world’s understanding of the risks to the world’s richest ocean ecosystems, says: “There is a possibility that sometime in the next 12 to 24 months we will see El Niño combine with rising sea temperatures to have a really big impact. influence. We are literally in uncharted territory that we know very little about and don’t know how to respond to, and I think we are dangerously vulnerable.”

“We don’t know the consequences of such a jump in temperature,” the scientist said, speaking from Dubai, where he is taking part in the Cop28 climate summit. “We could see storms that are even stronger than the ones we’ve seen. These are the warmest temperatures ever experienced on land and sea.”

Hoeg-Guldberg adds: “If this is something of a summer from hell, many of us fear that it could be a tipping point that we’ve passed, meaning we won’t be able to come back. We don’t know the consequences of such a sharp increase in temperature.”

Mass bleaching and mortality of corals in the Indo-Pacific region, which will lead to long-term damage to ecosystems and the millions of people in the Earth’s tropical regions that depend on them, could worsen if greenhouse gas emissions are not reduced, he said.

Tiny brown algae that live in corals are very sensitive to temperature changes. “Like us humans, there is a certain temperature at which we feel great. But then one or two temperatures above that and you’re dead. This is on a planetary scale. This is shocking.”

July 2023 saw the earth’s warmest day since 1910, as well as its warmest month in terms of upper sea temperatures.

Hoeg-Guldberg emphasizes: “What we know from 40 years of history is that there is a very strong, intimate relationship between that amount of energy in a system and the severity of storms and the impact on biological systems. It’s very well established.”

As coral reefs bleach and die, the habitat on which many reef-associated species depend disappears, leading to ecosystem collapse. According to the researchers, this could undermine up to 25% of ocean biodiversity.

He called on politicians and world leaders to “act faster and with more determination than ever before” to cut greenhouse gas emissions and “trust the science” to guide us.

“This is a science-based engineering problem,” Hoeg-Guldberg said. “We need to set parameters. We need to figure out how our planet works and do it in record time. Because we have the resources, we can do this. But we have to be smart and involve everyone. And make sure we get a system that will cool the planet for a while, or at least not increase the temperature for a while.”