Climate change’s influence on hurricanes
23rd Sep, 2022
Hurricane Fiona recently intensified into the 2022 Atlantic season's first major hurricane.
Hurricanes have three main parts:
- the calm eye in the center
- the eyewall where the winds and rains are the strongest
- the rain bands which spin out from the center and give the storm its size
- A hurricane is a large rotating storm with high speeds of wind that gust at least 74 mph that forms over warm waters in tropical areas.
- In the southern hemisphere, hurricanes rotate in a clockwise direction, and in the northern hemisphere they rotate in an anti-clockwise direction.
- This is due to what’s called the Coriolis force, produced by the Earth’s rotation.
How are hurricanes formed?
Hurricanes are given names by the World Meteorological Organisation (WMO) so that they can be distinguished.
- Hurricanes begin as tropical disturbances in warm ocean waters with surface temperatures of at least 80 degrees Fahrenheit (26.5 degrees Celsius). Those low-pressure systems are fed by energy from warm seas.
- Tropical Depression: A storm with wind speeds of 38 miles (61 km) an hour or less is classified as a tropical depression.
- Tropical storm: It becomes a tropical storm, when its sustained wind speeds top 39 miles (63 km) an hour.
The system divides storms into five categories:
- Category 1: Winds 74 to 95 mph (Minor damage)
- Category 2: Winds 96 to 110 mph (Extensive damage — Can uproot trees and break windows)
- Category 3: Winds 111 to 129 mph (Devastating — Can break windows and doors)
- Category 4: Winds 130 to 156 mph (Catastrophic damage — Can tear off roofs)
- Category 5:Winds 157 mph or higher (The absolute worst and can level houses and destroy buildings)
How climate change is impacting hurricanes?
- Rising temperature: Hurricanes feed off of heat energy, so as Earth's global temperatures continue to rise.
- Intensification: Climate change is making hurricanes wetter, windier and altogether more intense. There is also evidence that it is causing storms to travel more slowly, meaning they can dump more water in one place.
- Heavy rainfall: Climate change can also boost the amount of rainfall delivered by a storm. Because a warmer atmosphere can also hold more moisture, water vapour builds up until clouds break, sending down heavy rain.
- According to a recent study, during the 2020 Atlantic hurricane season (one of the most active on record), climate change boosted hourly rainfall rates in hurricane-force storms by 8%-11%.