Scientists want to know where all the heat trapped by greenhouse gases inside the Earth's atmosphere has gone. Now, researchers say most of the heat has flown to the Indian Ocean.
Experts have long suspected that the Earth's vast oceans are responsible for what they call a global warming hiatus, an unexpected pause in the rise of temperatures that began by the end of the 20th century, even as experts predicted the continual heating up of the Earth due to increasing carbon emissions.
The Pacific Ocean, with its warm waters on the western portion and the cold waters on the eastern side bringing about La Niña-like conditions since the beginning of the last century, was initially hypothesized as having absorbed most of Earth's heat content.
However, upon analyzing hydrographic data obtained from the U.S. National Oceanic and Atmospheric Administration's (NOAA) World Ocean Atlas (WOA), researchers led by oceanographer Dr. Sang-Ki Lee from the University of Miami found the upper 700 meters (2,300 feet) of the Pacific Ocean have in fact seen a temperature drop in recent years.
Instead, computer models built by Dr. Lee and his team have found that the strong easterly trade winds in the Pacific have driven the heat westwards via the Indonesian throughflow into the Indian Ocean, which the researchers believe has now held more than 70 percent of the world's heat since the start of the millennium.
The researchers say their findings are further confirmed by the increased water surge through the Makassar Strait, the largest channel in Indonesia found between the islands of Borneo and Sulawesi.
The new discovery helps provide insight into the importance of the Indonesian throughflow in providing air-conditioning to the rest of the world.
Dr. Lee says the heat collected in the upper Indian Ocean could be redistributed through other currents, such as the Agulhas current, a swift, strong boundary current on the western Indian Ocean that flows down the East Coast of Africa, and find its way to the Atlantic Ocean in the next few decades.
"If this warm blob of water in upper Indian Ocean is transported all the way to North Atlantic, that could affect the melting of Arctic sea ice," Dr. Lee told The Guardian. "That can also increase hurricane activity and influence the effects of drought in the U.S. There are simply hypotheses that need to be tested and studied in the future work."
The study is published in the latest issue of the Nature Geoscience journal.
Photo: Maureen Didde | Flickr
