New paper finds global cyclones have reached a historical low

A paper published today in the journal Geophysical Research Letters finds, "In the pentad since 2006, Northern Hemisphere and global tropical cyclone ACE (cyclone energy) has decreased dramatically to the lowest levels since the late 1970s. Additionally, the global frequency of tropical cyclones has reached a historical low." 

GEOPHYSICAL RESEARCH LETTERS, VOL. 38, L14803, 6 PP., 2011

Recent historically low global tropical cyclone activity

Key Points

• In the past 5-years, global tropical cyclone activity has decreased markedly
• Tropical cyclone ACE is modulated by ENSO and PDO on a global scale
• Heightened North Atlantic hurricane activity is not unexpected

Ryan N. Maue

Center for Ocean and Atmosphere Studies, Department of Earth, Ocean and Atmospheric Science, Florida State University, Tallahassee, Florida, USA

Tropical cyclone accumulated cyclone energy (ACE) has exhibited strikingly large global interannual variability during the past 40-years. In the pentad since 2006, Northern Hemisphere and global tropical cyclone ACE has decreased dramatically to the lowest levels since the late 1970s. Additionally, the global frequency of tropical cyclones has reached a historical low. Here evidence is presented demonstrating that considerable variability in tropical cyclone ACE is associated with the evolution of the character of observed large-scale climate mechanisms including the El Niño Southern Oscillation and Pacific Decadal Oscillation. In contrast to record quiet North Pacific tropical cyclone activity in 2010, the North Atlantic basin remained very active by contributing almost one-third of the overall calendar year global ACE.