Oceans are warming fast, study says
Scientists say the world’s oceans are warming far more quickly than previously thought, a finding with dire implications for climate change because almost all the excess heat absorbed by the planet ends up stored in their waters.
A new analysis, published Thursday in the journal Science, found that the oceans are heating 40 percent faster on average than a U.N. panel estimated five years ago. The researchers also concluded that ocean temperatures have broken records for several straight years.
“2018 is going to be the warmest year on record for the Earth’s oceans,” said Zeke Hausfather, an energy systems analyst at independent climate research group Berkeley Earth and an author of the study. “As 2017 was the warmest year, and 2016 was the warmest year.”
As the planet has warmed, the oceans have provided a critical buffer. They have slowed the effects of climate change by absorbing 93 percent of the heat trapped by the greenhouse gases humans pump into the atmosphere.
But the rising water temperatures are already killing off marine ecosystems, raising sea levels and making hurricanes more destructive.
As the oceans continue to heat up, those effects will become more catastrophic, scientists say. Coral reefs, whose fish provide key sources of protein to millions of people, will come under increasing stress. Rainier, more powerful storms will become more common, and coastlines around the world will flood more frequently.
Because they play such a critical role in global warming, oceans are one of the most important areas of research for climate scientists. Average ocean temperatures are also a consistent way to track the effects of greenhouse gas emissions because they are not influenced much by short-term weather patterns, Hausfather said. “Oceans are really the best thermometer we have for changes in the Earth,” he said.
But, historically, understanding ocean temperatures has also been difficult. An authoritative U.N. report, issued in 2014 by the Intergovernmental Panel on Climate Change, presented five different estimates of ocean heat, but they all showed less warming than the levels projected by computer climate models.
In the new analysis, Hausfather and his colleagues assessed three recent studies that accounted for older instrument biases. The results converged at an estimate of ocean warming that was higher than the IPCC predicted and more in line with the climate models.