NOAA: NUMEROUS HURRICANES NOT RELATED TO 'GLOBAL WARMING'

The nation is now wrapping up the 11th year of a new era of heightened Atlantic hurricane activity. This era has been unfolding in the Atlantic since 1995, and is expected to continue for the next decade or perhaps longer. NOAA attributes this increased activity to natural occurring cycles in tropical climate patterns near the equator. These cycles, called �the tropical multi-decadal signal,� typically last several decades (20 to 30 years or even longer). As a result, the North Atlantic experiences alternating decades long (20 to 30 year periods or even longer) of above normal or below normal hurricane seasons. NOAA research shows that the tropical multi-decadal signal is causing the increased Atlantic hurricane activity since 1995, and is not related to greenhouse warming.

The tropical multi-decadal signal presents itself in weather events around the world, including Atlantic hurricane variability. The tropical climate patterns producing the increased activity since 1995 are similar to those during the previous active hurricane era of the late 1920s to the late 1960s (1926-1970). These patterns are opposite to the below-normal hurricane era which ran from 1970 to 1994.

Since 1995, the tropical multi-decadal signal has produced lower wind shear (changing winds with height) and warmer waters across the tropical Atlantic, along with conducive winds coming off the west coast of Africa. This key combination of conditions produces active hurricane seasons.