  It has been proposed that the number of tropical cyclones as a function of
the energy they release is a decreasing power-law function, up to a
characteristic energy cutoff determined by the spatial size of the ocean basin
in which the storm occurs. This means that no characteristic scale exists for
the energy of tropical cyclones, except for the finite-size effects induced by
the boundaries of the basins. This has important implications for the physics
of tropical cyclones. We discuss up to what point tropical cyclones are related
to critical phenomena (in the same way as earthquakes, rainfall, etc.),
providing a consistent picture of the energy balance in the system. Moreover,
this perspective allows one to visualize more clearly the effects of global
warming on tropical-cyclone occurrence.
