Roger Pielke Jr. excerpts
from a study on tropical cyclones (hurricanes and typhoons) recently published in Nature Geoscience.
The bottom line? There has been no significant increase in cyclone activity beyond that which is attributable to natural variation.
In terms of global tropical cyclone frequency, it was concluded that there was no significant change in global tropical storm or hurricane numbers from 1970 to 2004, nor any significant change in hurricane numbers for any individual basin over that period, except for the Atlantic (discussed above). Landfall in various regions of East Asia during the past 60 years, and those in the Philippines during the past century, also do not show significant trends.
The data on the Atlantic does show an increase in activity, but is judged to be unreliable pre-1944, before the development of airborne observation and imaging of tropical storms.
The paper concludes:
. . . we cannot at this time conclusively identify anthropogenic signals in past tropical cyclone data.