The world's oceans have warmed rapidly over the last two decades, according to a new study published in the journal Nature Climate Change.
Researchers found that the oceans absorbed around the same amount of heat in the last two decades as they did over the course of 130 years before 1997. Some of that warming has been happening deep in the ocean, they found, which would explain where the heat was going during an apparent pause in rising surface temperatures scientists have observed in recent years. The ABC reports that this study supports scientific models that say global warming is still ongoing despite those cooler ocean surface temperatures:
A third of that recent build up, they found, occurred at depths of 700 metres or greater, beyond the reach of sunlight. This may explain a pause or "hiatus" in warming observed at the sea surface since the end of the 20th century, the study said.
"Over the past few decades the ocean has continued to warm substantially, and with time the warming signals are reaching deeper into the ocean," researcher Peter Gleckler, a scientist at the Lawrence Livermore National Laboratory in California, said in a statement.
The reasons for the temperature rises happening at deeper levels is not yet known. The study used data on ocean temperatures reaching back to the 1870s combined with modern temperature monitors and climate models. Scientists say that the world's oceans absorb more than 90% of the heat brought about by climate change.