5 Jun 2023
Is mass bleaching inevitable in 2023-2024?
El Niño is a natural phase in the Earth's climate cycle that occurs every 2-7 years. During El Niño events, ocean temperatures are higher than usual. But while El Niño is a natural element of the Earth's climate cycle, its impacts are becoming increasingly severe under human-induced climate change. One major consequence is the rise in mass coral bleaching events, threatening the marine ecosystems that support ocean biodiversity and provide vital resources for human communities.
Coral bleaching occurs when corals expel the symbiotic algae, known as zooxanthellae, that live within their tissues. This loss deprives them of essential nutrients and leaves them stressed and vulnerable to disease. With prolonged exposure to unusually warm water—a hallmark of strong El Niño events—the intensity and frequency of these bleaching events have escalated dramatically. Scientific studies have revealed that recent El Niño episodes have been stronger and more unpredictable, further endangering coral reefs around the globe.
In May, our team observed mild, yet widespread, coral bleaching as temperatures exceeded the coral's 'comfort zone' for two consecutive weeks. This is not great news, since El Niño will push warm water eastwards to Southeast Asia.
On land, the repercussions of an intensifying El Niño are equally concerning. In Southeast Asia, the phenomenon brings hot, dry conditions that lead to severe droughts and forest fires. These dry spells compromise agricultural productivity and exacerbate air quality issues, as widespread fires generate extensive haze that affects human health and disrupts daily life. The cascading effects of these dry and hot conditions underscore the interconnectedness of our planet's climate system, where changes in ocean temperatures influence weather patterns and environmental stability across continents.
As communities worldwide brace for continued heat and prolonged drought well into 2023-2024, it becomes increasingly urgent for governments and environmental agencies to take proactive measures, from emergency response planning to long-term strategies for mitigating climate change. This multifaceted approach is crucial for protecting our coral reefs and safeguarding livelihoods and natural habitats intrinsically linked to our planet's health.