This color-enhanced composite satellite image shows Hurricane Ivan, one of four major hurricanes that pummeled the Florida coast in 2004. [Photo]

　　Climate change could make future hurricanes stronger, but whether the effect is measurable is still a matter of debate. It is also unknown whether it will change the total number of storms.

　　Trends in human-influenced environmental changes are now evident in hurricane regions. These changes are expected to affect hurricane intensity and rainfall, but the effect on hurricane numbers remains unclear. The key scientific question is how hurricanes are changing.