Has There Been Any Discernible Human Influence on Atlantic Hurricane Climate?

Detection and attribution of a human influence on climate, or some aspect of climate such as hurricane frequency, involves detection of an unusual change (outside the range of internal climate variability) in the data, and then attribution of the change to a specific anthropogenic influence, such as increasing greenhouse gas concentrations or anthropogenic aerosols. Attribution as used here means that the observed change is demonstrated to be consistent with the expected anthropogenic influence based on physical understanding (typically as incorporated in models and theory), and that the change is not consistent with alternative explanations, such as internal variability or volcanic forcing.