James Hansen is in charge of GISS. He's sort of a global warming celebrity.
"thats why we are getting more frequent and stronger hurricanes."
This could be another explanation:
A NOAA-led team of scientists has found that the apparent increase in the number of tropical storms and hurricanes since the late 19th and early 20th centuries is likely attributable to improvements in observational tools and analysis techniques that better detect short-lived storms.
The new study, reported in the online edition of the American Meteorological Society’s peer-reviewed Journal of Climate, shows that short-lived tropical storms and hurricanes, defined as lasting two days or less, have increased from less than one per year to about five per year from 1878 to 2008.
“The recent jump in the number of short-lived systems is likely a consequence of improvements in observational tools and analysis techniques,” said Chris Landsea, science and operations officer at NOAA’s National Hurricane Center in Miami, and lead author on the study. “The team is not aware of any natural variability or greenhouse warming-induced climate change that would affect the short-lived tropical storms exclusively.”
Several storms in the last two seasons, including 2007’s Andrea, Chantal, Jerry and Melissa and 2008’s Arthur and Nana, would likely not have been considered tropical storms had it not been for technology such as satellite observations from NASA’s Quick Scatterometer (QuikSCAT), the European ASCAT (Advanced SCATterometer) and NOAA’s Advanced Microwave Sounding Unit (AMSU), as well as analysis techniques such as the Florida State University’s Cyclone Phase Space.
A recent study published in the Journal of Climate concludes that the prevalence of hurricanes has not increased, nor has their intensity. The apparent increase in both is due to improved tracking and documentation of the storms. Another study, also published in the Journal of Climate, also reports an upward trend in the number and intensity of hurricanes. This study also stops short of confirming that the actual number of storms has increased and also proposes that better data collection and record keeping impacted the upswing.