Climate Change: Man-Made Heat In World's Oceans Has Spiked Dramatically Since 1997

The ocean, in a huge spike in warming, has absorbed the same amount of man-made heat since 1997 as it did in the previous nearly century and a half, according to a study released Monday. Of that heat energy from global warming, humans are responsible for more than 90 percent of what goes into the world's bodies of water instead of the ground.

"The changes we're talking about, they are really, really big numbers," said study co-author Paul Durack, an oceanographer at the Lawrence Livermore National Lab in California, told the Associated Press. "They are nonhuman numbers."

The study, published in the journal Nature Climate Change, looked at how much man-made heat has been absorbed by the seas over the past 150 years. Researchers found that around 150 zettajoules (a zettajoule is 1 sextillion joules) of energy were put into the ocean from 1865 to 1997, but then, over just the next 18 years, the oceans absorbed another 150 zettajoules of energy. That is roughly the amount of heat energy in 500,000 lightning bolts per second, according to climate change blog Science Skeptic.

For the most part, the heat has been confined to the 2,300 feet below the ocean's surface, but the deeper oceans have been rapidly absorbing more energy each year. The increase seen in the amount of heat energy in the oceans reflect the Earth's climate system overall, according to the study.

"After 2000 in particular, the rate of change is really starting to ramp up," Durack said.

But as the oceans get warmer, the less heat they can absorb, forcing more heat energy to travel into the air and onto the Earth's surface.

"These findings have potentially serious consequences for life in the oceans as well as for patterns of ocean circulation, storm tracks and storm intensity," said Jane Lubchenco, Oregon State University marine sciences professor and former chief of the National Oceanic and Atmospheric Administration.

Some experts say that the amount of heat put into the ocean is dramatically more than what the study found. Another scientist, Kevin Trenberth, climate analysis chief at the National Center for Atmospheric Research, who was uninvolved in the research, said the study "significantly underestimates" how much heat lies underwater, according to the Associated Press.