New research indicate that the unexpected flattening of global temperatures in recent years is linked to cooling temperatures in the tropical Pacific.
Cooling sea-surface temperatures in the tropical Pacific Ocean — a phase that is part of a natural warm and cold cycle — may explain why global average temperatures have stabilized in recent years, even as greenhouse gas emissions have been warming the planet, according to new research.
The findings suggest that the flattening in the rise of global temperatures recorded over the past 15 years are not signs of a "hiatus" in global warming, but are tied to cooling temperatures in the tropical or equatorial Pacific Ocean. When the tropical Pacific naturally switches back into a warm phase, the long-term trends in global warming, including more steeply rising global temperatures, will likely increase, said study co-author Shang-Ping Xie, a climate scientist at the University of California, San Diego.
"The engine driving atmospheric circulation on global scales resides in the tropical Pacific," Xie told LiveScience. "When the natural cycle shifts the next time to a warmer state, we're going to see more extreme warming on the global scale." [The Reality of Climate Change: 10 Myths Busted]
In early May, a carbon dioxide monitor in Hawaii recorded the proportion of carbon dioxide in the atmosphere as being more than 400 parts per million (ppm) for the first time in human history, breaking a 3-million-year-old record. (Parts per million means that, in this example, for every million molecules of air, 400 of them are carbon dioxide.) But, over the past 15 years, global average temperatures have stabilized rather than sharply increased, as previous predictions suggested they should have, mystifying climate scientists and adding fuel to the fire for climate change skeptics.
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