Study Finds Indian, Pacific Oceans Temporarily Hide Global Warming

A new NASA study of ocean temperature measurements shows in recent years extra heat from greenhouse gases has been trapped in the waters of the Pacific and Indian oceans. Researchers say this shifting pattern of ocean heat accounts for the slowdown in the global surface temperature trend observed during the past decade. Jet Propulsion Laboratory (JPL), CA, found a specific layer of the Indian and Pacific oceans between 300 and 1,000 ft below the surface has been accumulating more heat than previously recognized. They also found warm water movt has affected surface temps.

“Greenhouse gases continued to trap extra heat (in the 20th century), but for about 10 years starting in the early 2000s, global average surface temperature stopped climbing, and even cooled a bit,” said Willis. In the study, researchers analyzed direct ocean temperature measurements, incl observations from a global network of about 3,500 ocean temperature probes known as the Argo array >> show temperatures below the surface have been increasing.

Since 2003, unusually strong trade winds and other climatic features have been piling up warm water in the upper 1,000 feet of the western Pacific, pinning it against Asia and Australia. “The western Pacific got so warm that some of the warm water is leaking into the Indian Ocean through the Indonesian archipelago,” said Nieves, the lead author of the study. The movement of the warm Pacific water westward pulled heat away from the surface waters of the central and eastern Pacific, which resulted in unusually cool surface temperatures during the last decade. Because the air temperature over the ocean is closely related to the ocean temperature, this provides an explanation for the global cooling trend in surface temperature.

Cooler surface temperatures also are related to a long-lived climatic pattern called the Pacific Decadal Oscillation, which moves in a 20 – 30 yr cycle. It has been in a cool phase during the entire time surface temperatures showed cooling, bringing cooler-than-normal water to the eastern Pacific and warmer water to the western side. But “Given the fact the Pacific Decadal Oscillation seems to be shifting to a warm phase, ocean heating in the Pacific will definitely drive a major surge in global surface warming,” Nieves said.

Pauses of a decade or more in Earth’s average surface temperature warming have happened before in modern times, with one occurring between the mid-1940s and late 1970s.”In the long term, there is robust evidence of unabated global warming,” Nieves said. http://go.nasa.gov/1UJRfXc