A new analysis of weather patterns in the Pacific Ocean concluded that the warmer temperatures in the American Northwest are caused by changes in ocean winds, and not the result of human activities.
Scientists have long known that sea surface temperatures are lower when strong winds whip up ocean waves, and higher when the seas are calm, according to the New York Times. Aside from these natural causes, early studies also linked higher levels of carbon dioxide brought by human activities as one of the unnatural causes.
But, a new analysis that focused on barometric pressure, temperature and wind patterns recorded as early as 1900 until 2012, argued that human activities and carbon dioxide levels are minor contributors to the trend.
"The concept of winds controlling or affecting ocean temperature in that very way is not controversial, but the strength of that relationship was quite amazing," said James Johnstone, a climatologist from the University of Washington's Joint Institute for the Study of the Atmosphere and Ocean. "It explains practically every wiggle in the ocean temperature variations. It's a phenomenal correlation."
Although the study showed that wind patterns are the main causes of temperature variation, that may not be the case in other parts of the world. The reviewed data was taken from Alaska, Hawaii and California, and the locations may have influenced the results. Further analysis is needed to fully establish the role of shifting wind patterns responsible for changing temperatures.
Researchers reviewed weather records gathered by ships and advanced weather-monitoring devices to create climate change computer models. The simulations proved that there is no direct link between wind changes and the increasing levels of carbon dioxide; water became warmer when carbon dioxide levels were reduced.
But, climate scientist Kevin Trenberth from the National Center for Atmospheric Research in Boulder, Colorado, is not convinced by the results. He argued that the data back then was poor and unreliable.
"There is no doubt that regionally, the changes in temperature are dominated by changes in the atmospheric circulation that likely have little or nothing to do with climate change, but this does not call into question the concept of global warming," Trenberth told the Los Angeles Times.
Further details of this study were published in the Sept. 25 issue of Proceedings of the National Academy of Sciences.
