A method of vaporizing liquefied natural gas includes passing liquefied natural gas through a submerged combustion vaporizer having a water bath at a bath temperature and a burner to provide a vaporized gas output at a send-out temperature, drawing water from the bath of the submerged combustion vaporizer and supplying it to an atmospheric heating tower having an ambient air temperature, returning water from the atmospheric heating tower to the bath of the submerged combustion vaporizer, modulating the operating rate of the burner of the submerged combustion vaporizer, and modulating the operating rate of the atmospheric heating tower.