A Hurricane's Purpose

Many see hurricanes as only destructive forces of nature that reck property, ruin crops and overall destroy 

livelihoods. The task of rebuilding is always a long and challenging one, be it a human community or wildlife. But there is always some good in the bad, as nature has a way of balancing everything.

Believe it or not hurricanes actually help corals around its vicinity by reducing the Earth’s temperature. 

According to the article “Hurricanes and their Effects on Coral Reefs” published by the Global Coral Reef 

Monitoring Network, there are three ways in which hurricanes can do this [1]. They are:

1) Hurricanes use heat as an energy source. As stated in a previous post, hurricanes need certain conditions to form, one being warm waters. They take up heat from the upper water column and surface water through latent heat of vapourization, where energy is absorbed to change its physical state while maintaining it temperature.[2]. The heat energy absorbed, fuels the hurricane, while the energy lost from the ocean, cools it.

Image Credit: Yiqi Shao

2)Turbulent waves bring up cooler water. The massive disturbance that a hurricane creates can change the sea surface temperature, which is the temperature of the ocean’s surface millimeter [3]. The wind created by the hurricane turns the water creating waves, which can turn the water, bringing cooler water to the surface. This mixing of temperatures, reduces the sea surface temperature. Of course the extent of this depends on the wind speed and depth of ocean.

Image Credit: EOSC 114

3)Clouds shade the ocean from the sun. The cloud of a hurricane can stretch for miles, covering a significant portion of the Earth. This cloud cover prevents the Sun’s UV light from reaching the ocean’s surface. This gives the water a chance to cool by releasing heat into the atmosphere. The clouds also reflect the sunlight back out into space so the atmosphere cools as well [4].  

Photo Credit: NASA Satelites 

Image Credit: NASA ClimateKids

Once the temperature of the water is decreased, it removes thermal stress from the coral, stopping coral 

bleaching [5]

Next time you wonder why something as destructive as a hurricane existe, imagine if hurricanes were not 

here to regulate ocean temperature. The seas would boil. All the coral in the tropics would begin bleaching, 

and eventually die. Many reef species would be left without shelter or food, leading to the extinction of some 

species. This would then cause a collapse in the marine food web and the starvation of millions of people 

who depend on the ocean for food. Not to mention, if oceans ever reach their limit of heat absorption, it 

would remain trapped in the atmosphere, slowly baking the Earth.

References:

[1] HURRICANES, BACKGROUND TO. “3 Hurricanes and their effects on coral reefs.” Status of 

Caribbean coral reefs after bleaching and hurricanes in 2005 31 (2008).

https://cmsdata.iucn.org/downloads/status_carib_corals.pdf#page=39

[2] https://www.britannica.com/science/latent-heat

[3] https://earthobservatory.nasa.gov/global-maps/MYD28M

[4] https://climatekids.nasa.gov/review/greenhouse-effect/clouds-cool.html [5]https://coralreefwatch.noaa.gov/satellite/bleachingoutlook/descriptions/demo_background_stress.php