Data show U.S. riding out worst storms on record - USATODAY.com

Some meteorologists say the increased storm activity is caused by a naturally occurring cycle of activity that hatches more storms in the Atlantic.

"These are likely due to a natural climate fluctuation in the Atlantic," said Chris Landsea, a scientist with the National Hurricane Center in Miami.

Kerry Emanuel, a scientist at the Massachusetts Institute of Technology who has studied climate effect on hurricanes, says global warming and human-caused climate change is contributing. But Landsea has said evidence that global warming is affecting hurricanes "is pretty darn tiny."