Human activities intensify hurricanes breeding

Human activities are responsible for the rise in ocean temperatures in hurricane affected areas of the Atlantic and Pacific oceans, atmospheric scientists from U.S. said on Monday.

The study unleashed online in the Proceedings of the National Academy of Sciences on September, 11 reveals a substantial human effect on the climate. Human-induced increases in greenhouse gas concentrations may raise ocean temperatures in hurricanes born in the tropical waters of the Atlantic and Pacific oceans.

In their study, the atmospheric scientists from the Lawrence Livermore National Laboratory (LLNL), National Center for Atmospheric Research, and other institutions have indicated that the rising of sea surface temperatures of the tropical Atlantic and Pacific oceans over the last century is linked to human activities.

The climate experts, headed by Ben Santer at LLNL in California, studied 22 different climate models to investigate the possible causes of a rise in sea surface temperatures of up to 0.67C in the Atlantic and Pacific tropics from 1906 to 2005. Each computer model of climate system was run several times to check out how much sea surface temperatures would have warmed with and without rising levels of greenhouse gases and other pollutants.

After observing the models, the researchers found that while the increasing temperatures in the Atlantic and Pacific hurricane areas are not the sole determinant of hurricane intensity, still they are likely to be one of the most meaningful factors. "This clearly shows that the observed increases in ocean temperatures in these Atlantic and Pacific hurricane breeding grounds simply can't be explained without positing a large human affect," Ben Santer said. "Climate noise alone just won't cut it."

The experts noted that emissions from burning fossil fuels and other industrial activities were to blame for driving temperatures upwards in tropical waters where hurricanes form. They assert warmer ocean waters will prompt hurricanes and make them more vigorous.

Hurricanes are complicated phenomena that are influenced by a variety of physical factors, like sea surface temperatures, wind shear, water vapor and atmospheric stability, the study said.

If sea temperatures and global climate warming continue to rise, scientists fear that category four and five hurricanes, such as Katrina, which mangled New Orleans last summer, will become more common place.

"It is important to note that we expect global temperatures and sea surface temperatures to increase even more rapidly over the next century," said Tom Wigley, a co-author of the study.

Concerned with the worst-case scenario of undiminished future carbon emissions, which predict ocean temperatures will rise as much as nine degrees by the end of the century and could be disastrous, Santer said, "The results give me cause for concern," and "We can't stick our heads in the sand here."