The study did not conclude more hurricanes. Unfortunately, uneducated people and journalists read single sentence in a summary and write entire articles about incorrect conclusions. Climate change won't alter what is needed for a hurricane to form like low shear and a lack of dry air advection. They also don't change steering currents and formation locations. Once they do form, a much larger percentage of them will be major. We have been incredibly lucky in that most large hurricanes that have formed this year have remained away from the coasts of the US.

And yes, 193 of 196 countries signed the Paris Climate agreement. Edit: what I read was wrong. The only non-signatories are Iraq, Syria, Nicaragua and Uzbekistan.