The study further indicated that during 2023 and 2024, nearly 10 percent of the entire ocean areas hit record-high temperatures, consequently having devastating imprints on coral reefs, fisheries, and coastal communities, with an indirect after-effect on inland communities.
By Salam Rajesh
Intensifying marine heatwaves are driving ocean temperatures to record-breaking levels, surpassing anything observed in modern history. These extreme warming events are fueled by climate change, and are disrupting marine ecosystems, threatening fisheries, and intensifying severe weather patterns.
This hard-hitting observation comes from Dr Karen Filbee-Dexter of the University of Western Australia and the Institute of Marine Research, Norway, while calling for urgent actions to reduce global emissions and prevent further extreme temperatures in the oceans.
Elaborating on this concerning development, a new study published in Nature Climate Change found that there were up to 3.5 times the number of marine heatwave days in the summers of 2023 and 2024 as compared to any other year on record.
The study highlighted that during the past two years, climate change processes exacerbated by a persisting El Niño effect caused multiple record-breaking marine heatwaves, implicating damages around the world to the tune of billions of dollars.
The study further indicated that during 2023 and 2024, nearly 10 percent of the entire ocean areas hit record-high temperatures, consequently having devastating imprints on coral reefs, fisheries, and coastal communities, with an indirect after-effect on inland communities.
Scientists studying the process warned that as long as the rate of human-induced climate change keeps rising, marine heatwaves will continue to worsen. To stall this, more proactive action is needed to avert the damages that extreme ocean temperatures are already causing globally, they re-emphasized.
Across Asia, rising ocean temperatures intensified storms, including Typhoon Doksuri, Severe Cyclonic Storm Remal, and Tropical Cyclone Mocha, which together affected millions and caused hundreds of deaths, the study noted.
Marine heatwaves contributed to record-breaking heatwaves and severe flooding in Japan, while warming waters created marine ‘dead zones’ leading to mass fish deaths and harming aquaculture in the Gulf of Thailand and the Malacca Straits, according to the study’s finding. There was widespread coral bleaching across Asia, leading to diving restrictions in Thailand to aid reef recovery, it noted.
Elaborating further on the consequential impact of rising ocean temperatures, the study authors pointed finger to the marine heatwave that fueled Cyclone Gabrielle in New Zealand during 2023, killing 11 people and causing a massive 8 billion US Dollar worth of loss and damage in the oceanic country.
The list of damages incurred across the globe is unending. For instance, marine heatwaves caused Peruvian anchovies to move away from their usual waters, leading to the closure of commercial fisheries during 2023 and 2024, incurring an estimated loss to the tune of 1.4 billion US Dollars.
Nearly 6,000 people died in Libya during 2023 when heavy rains infused by Storm Daniel caused the collapse of the Derna Dam, which observers said was the deadliest single flood event on record in Africa. Storm Daniel was made more intense and rainy due to sea temperatures made higher by climate change, the study authors noted.
Reflecting on these outcomes, Ilana Victorya Seid, Chair of the Association of Small Island States, stressed that marine heat waves, fueled by the relentless burning of fossil fuels, are ravaging reefs, depleting fisheries, and unraveling the delicate balance that has sustained people for generations.
“For us, this is not just an environmental issue, it is a matter of survival, of identity, of home. The world’s biggest polluters must recognize that their fate is tied to ours. We urge them to take responsibility because when the ocean can no longer sustain us, it will no longer sustain them either”, Seid puts it blatantly in summing up the impact scenario of rising ocean temperatures and the escalating marine heat wave experience.
While El Niño exacerbated marine heatwaves during 2023 and 2024, previous research showed that human-induced climate change had already caused a 50 percent increase in marine heatwaves between 2011 and 2021.
Speaking plainly as a matter of fact, Seid says that, “If we keep burning fossil fuels and cutting down forests, marine heatwaves could be 20-50 times more frequent and ten times more intense by the end of the century. Replacing oil, coal and gas with renewable energy is therefore vital to safeguard ocean life and coastal communities”.
The ocean plays vital roles in regulating the climate, supporting marine life, and providing food and jobs for billions of people. However, the researchers say that as marine heatwaves worsen with climate change, these functions are at risk.
During the past two years, marine heatwaves had forced the closure of fisheries and aquaculture, increased whale and dolphin strandings, and had caused the fourth global coral bleaching event. The impacts did not stop at the oceans, marine heatwaves had driven extreme weather such as deadly atmospheric heatwaves and flooding on land, the study authors stressed.
All is not lost though, so much as the study pointed out that good forecasting and prompt action reduced the impacts of some cases of marine heatwaves, such as, in Australia, a quarter of the population of endangered Red Handfish was taken into aquariums before the marine heatwave hit, and released again when the waters cooled.
Citing another example, the authors pointed out that in the United States, corals and conches were moved into deeper, cooler waters, while in Peru, the government paid benefits to the fishers who could not go to sea when they were forced to close the anchovy fishery. Better forecasting and rapid response plans would have reduced disastrous impacts in other regions, the study noted.
Rising ocean surface temperature is also linked to successive development of depressions in the Indian Ocean, subsequently giving rise to cyclonic storm formation one after the other in quick succession, causing heavy loss and damage along the coastal regions and further inland across the Indian mainland. Several parts of North East India were neither spared from the harsh reality of extreme weather events, causing massive loss and damage. And, as the study suggests, things are likely to get worse by the year.