Reduction in airborne dust responsible for recent warming trend in Atlantic Ocean

Washington, March 27 (ANI): A new study has determined that the recent warming trend in the Atlantic Ocean is largely due to reductions in airborne dust and volcanic emissions during the past 30 years.

Since 1980, the tropical North Atlantic has been warming by an average of a quarter-degree Celsius (a half-degree Fahrenheit) per decade.

"Though this number sounds small, it can translate to big impacts on hurricanes, which thrive on warmer water," said Amato Evan, a researcher with the University of Wisconsin-Madison's Cooperative Institute for Meteorological Satellite Studies and lead author of the new study.

For example, the ocean temperature difference between 1994, a quiet hurricane year, and 2005's record-breaking year of storms, was just one degree Fahrenheit.

More than two-thirds of this upward trend in recent decades can be attributed to changes in African dust storm and tropical volcano activity during that time, report Evan and his colleagues at the UW-Madison and the National Oceanic and Atmospheric Administration.

In the new study, they combined satellite data of dust and other particles with existing climate models to evaluate the effect on ocean temperature.

They calculated how much of the Atlantic warming observed during the last 26 years can be accounted for by concurrent changes in African dust storms and tropical volcanic activity, primarily the eruptions of El Chichon in Mexico in 1982 and Mount Pinatubo in the Philippines in 1991.

In fact, it is a surprisingly large amount.

"A lot of this upward trend in the long-term pattern can be explained just by dust storms and volcanoes," said Evans.

"About 70 percent of it is just being forced by the combination of dust and volcanoes, and about a quarter of it is just from the dust storms themselves," he added.

The result suggests that only about 30 percent of the observed Atlantic temperature increases are due to other factors, such as a warming climate.

While not discounting the importance of global warming, Evan said that this adjustment brings the estimate of global warming impact on Atlantic more into line with the smaller degree of ocean warming seen elsewhere, such as the Pacific.

"This makes sense, because we don't really expect global warming to make the ocean temperature increase that fast," he said. (ANI)