The world's oceans have absorbed 90 percent of the heat trapped by humanity's greenhouse gas emissions, which is equivalent to an atomic bomb going off every second for the past 150 years, according to an analysis of a new study.
A team of international researchers reconstructed ocean warming from 1871 to the present and found that the world's oceans have warmed roughly 1,000 times more than the annual global energy consumption by humans, according to a press release.
Calculations of the data presented in the study published this week in the journal Proceedings of the National Academy of Sciences reveal that the amount of energy absorbed is equivalent to what is generated by roughly 1.5 Hiroshima-size atomic bombs per second over the past 150 years.
Because heating has accelerated with rising emissions, the equivalent heat being absorbed by the world's oceans is three to six bombs per second today, depending on the time frame used.
Laure Zanna, lead author of the study and a physics professor at Britain's University of Oxford, told weather.com her team does not like to use the metaphor of an atomic bomb to explain the amount of heat absorbed by the ocean's over the past 150 years.
"I do not think that these are relevant to explain our work," Zanna said. "However, our team has estimated that the amount of energy is roughly 1,000 times annual worldwide human primary energy consumption."
Most global estimates of ocean warming didn't begin until the 1950s because of a lack of data. The international team of researchers reconstructed warming using a mathematical approach originally developed by Oxford's Samar Khatiwala that was able to reconstruct manmade carbon uptake by the ocean from as early as 1871.
"Our reconstruction is in line with other direct estimates and provides evidence for ocean warming before the 1950s," Zanna said.
Khatiwala said in the press release that the reconstruction is "akin to ‘painting’ different bits of the ocean surface with dyes of different colors and monitoring how they spread into the interior over time."
"If we know what the sea surface temperature anomaly was in 1871 in the North Atlantic Ocean, we can figure out how much it contributes to the warming in, say, the deep Indian Ocean in 2018," he added.
The researchers note that within the last 60 years, changes in ocean circulation are responsible for up to half the observed warming and associated sea level rise in low- and mid-latitudes of the Atlantic Ocean.
While the change in ocean circulation has been conclusively identified, the researchers say they cannot yet pin it solely on human-induced causes. Solving this mystery is a goal for future studies, the researchers said.
"In addition to providing an extended baseline for ocean warming, we have found that changes in ocean transport are important in shaping patterns of warming and associated sea level change in the Atlantic Ocean," Zanna said. "In the future, we do expect further changes in ocean transport; our work can help understand how the circulation will influence regional climate change and potentially help constrain regional sea level projections."