... which causes cooling. Every model I have looked at shows that concentrated convection causes cooling. The subsidence around hurricanes cools and is much larger than the hurricane itself. Another factor is that tropical convection (not just hurricanes) peaks at night and therefore so do the cold cloud tops which warm the planet. There are probably other factors, but basically this increase in storminess is a sure sign of negative feedback from warming oceans.
Atmospheric or oceanic surface cooling?