Climate change: Indian Ocean racing towards unprecedented heatwave crisis

The Indian Ocean, a vital body of water bordered by 40 countries and home to a third of the global population, is rapidly moving towards a state of near-permanent marine heatwaves.

The condition could lead to catastrophic consequences for the region’s marine ecosystems and coastal communities.

A comprehensive new study led by Roxy Mathew Koll of the Indian Institute of Tropical Meteorology paints a dire picture of the accelerating climate changes unfolding in the Indian Ocean. The research, published by Elsevier, forecasts substantial ocean warming, rising sea levels, and an increase in the frequency and intensity of extreme weather events.

While the Indian Ocean has historically warmed at a rate of 1.2 degree Celsius per century, climate models now predict this pace could accelerate to between 1.7 degree Celsius and 3.8 degree Celsius per century by 2100 under high emissions scenarios.

This rapid warming is not limited to the surface – the heat content of the Indian Ocean down to 2,000 meters is currently increasing at a rate of 4.5 zettajoules per decade, a figure projected to skyrocket to 16-22 zettajoules per decade in the coming years.

“The future increase in heat content is comparable to adding the energy equivalent of one Hiroshima atomic bomb detonation every second, all day, every day, for a decade,” warned Koll.

This alarming trend is driving the Indian Ocean towards a near-permanent state of marine heatwaves, with the number of heatwave days per year expected to surge from the current 20 to a staggering 220-250 by 2050.

“The Indian Ocean, a climate change hotspot, faces rapid and strong increases in marine heatwave frequency and intensity unless global CO2 emissions are substantially cut,” said co-author Thomas Frolicher.

These prolonged heatwaves will have devastating consequences for the region’s marine ecosystems, causing widespread coral bleaching, seagrass destruction, and the collapse of kelp forests. The impacts will reverberate through coastal communities, many of whom rely on fisheries for their livelihoods.

The study also warns of other worrying changes, including a shift in the seasonal temperature cycle that could fuel more extreme rainfall events and cyclones. Ocean acidification is also set to intensify, threatening calcifying marine organisms.

“It is crucial to recognize that the impacts of these changes are not distant concerns for our grandchildren and future generations alone,” Koll emphasised. “As the current generation, we are already witnessing the repercussions firsthand.”

Urgent action is needed to mitigate the Indian Ocean’s slide towards a near-permanent heatwave state, the researchers urge. This will require a multipronged approach encompassing global emissions cuts, resilient infrastructure, sustainable marine practices, enhanced forecasting, and international cooperation, the researchers added.