The world’s oceans are heating up at levels equivalent to dropping five Hiroshima bombs every second, new research has found.
The startling study revealed 2019 was another unprecedented year for global warming, with sea temperatures reaching the highest ever recorded.
A team of international scientists looked at ocean temperatures from the sea’s surface to up to 2,000 metres deep, going back more than half a century.
They described the upward trend in warming as “relentless”, noting the temperature increase over the past 25 years equated to 3.6 billion Hiroshima atom bombs.
“There are no reasonable alternatives aside from the human emissions of heat-trapping gases to explain this heating,” associate professor Lijing Cheng, the paper’s lead author, told CNN.
“The Hiroshima atom-bomb exploded with an energy of about 63,000,000,000,000 Joules.
“I did a calculation ... the amount of heat we have put in the world’s oceans in the past 25 years equals to 3.6 billion Hiroshima atom-bomb explosions.”
The new study, titled 'Record-Setting Ocean Warmth Continued in 2019', was published in the journal Advances in Atmospheric Sciences on Monday.
Researchers found that while oceans had warmed steadily between 1955 and 1986, temperatures had accelerated far more rapidly in recent decades.
Scientist concluded that since 1970, more than 90 per cent of the world’s excess heat had been absorbed by the Earth’s oceans.
Sea temperatures serve as an excellent indicator of global climate change because of their ability to soak up energy imbalances.
“Because the oceans are the main repository of the Earth’s energy imbalance, measuring ocean heat content is one of the best way to quantify the rate of global warming,” the report said.
“These data reveal that the world’s oceans in 2019 were the warmest in recorded human history.
“The past five years are the top five warmest years in the ocean historically with modern instruments, and the past 10 years are also the top 10 years on record.”
The study also highlighted the potentially devastating impact such increases in sea temperature levels could have on the wider environment.
Researchers said warmer waters meant reduced ocean oxygen levels, significantly affecting “sea life, particularly corals and other temperature and chemistry-sensitive organisms”.
Additionally, they noted rising ocean temperatures led to greater water evaporation, with extra moisture in a warmer atmosphere causing more extreme weather.
“The ocean heating is irrefutable, and a key measure of the Earth’s energy imbalance,” the paper’s authors said.
“More than 90 per cent of the heat accumulates in the ocean because of its large heat capacity, and the remaining heating manifests as atmospheric warming, a drying and warming landmass, and melting of land and sea ice.
“Increasing heat increases evaporation, and the extra moisture in the warmer atmosphere nourishes heavy rains and promotes flooding, leading to more extreme weather, in particular hurricanes and typhoons.”
