A slick idea, so to speak; +
Hurricanes do cool down the ocean by facilitating evaporation. Evaporation of a liquid carries heat away from that liquid. We facilitate evaporation of a hot cup of coffee by blowing on it and so offering more air into which the coffee might evaporate and so cool. Hurricanes facilitate evaporation 3 ways.
1: Warm air. Warm air can carry more moisture than cold air. That is why you can see your breath on a cold day - as your breath cools in the outside air, its water carrying capacity drops and you see the condensed water droplets. A hurricane brings warm air to the ocean surface where it collects evaporation.
Low pressure air. Hurricanes have low pressure air. The lower the pressure in the overlying air the easier it is for water to evaporate off and stay there. A phase change from liquid to gas is easier when there are fewer gas molecules already up there crowding around. At altitude things evaporate faster and water boils cooler.
Air exchange. Just like blowing on your coffee, the air exchange caused by the hurricane offers new air, not saturated with water, to come in and remove evaporate from the ocean surface. From
As the warm air continues to rise, the surrounding air swirls in to
take its place. As the warmed, moist air rises and cools off, the
water in the air forms clouds. The whole system of clouds and wind
spins and grows, fed by the ocean's heat and water evaporating from
The net effect: the circumstances of the hurricane make a feedforward loop which allows the hurricane to take more heat energy from the ocean and build in strength. This is why hurricanes Peter out once they get over land.
But disrupting that loop - how to do it... You would need to prevent evaporation from the ocean surface over a large area.
You could achieve that with an enormous oil slick. Water cannot evaporate up through an overlying layer of oil.
The worst oil spill in history wasn't an accident — it was deliberate.
During the Gulf War, Iraqi forces attempted to prevent American
soldiers from landing by opening valves at an offshore oil terminal
and dumping oil from tankers. The oil resulted in a 4-inch thick oil
slick that spread across 4,000 square miles in the Persian Gulf.
If you could shut down evaporation from a large enough surface of ocean by means of an oil slick, you could cut the growth engine of the hurricane. "Wah!" you may protest in the comments. "Wah! The tragedy of oil slicks!" Do a cost analysis before you wah so much. It is not outrageous especially as Mother Nature and her petro-hungry microbes do most of the oil slick cleanup gratis.
As scifi premises go I think this one is fairly awesome.