Rising sea temperatures could soon land Europe in hot water as hurricanes get closer and closer to the mainland. This comes after Hurricane Lorenzo, the easternmost category 5 hurricane ever to be recorded, hit the Azores and continued towards Ireland and southwest England.

Hurricane Lorenzo got further east than any hurricane

Described as the weirdest storm of the 2019 Atlantic hurricane season, Hurricane Lorenzo sparked major concerns across Europe and reignited the debate on climate change. The hurricane is the easternmost category 5 hurricane ever to be recorded, which scientists say is due to rising water temperatures on earth.

Hurricanes - defined as large, rotating storms with sustained high-speed winds - form over water in tropical areas. For this to happen, the surface water temperature has to be at least 26 degrees, along with several other conditions; conditions that are usually found on the warmer western side of the Atlantic. However, Lorenzo formed south of Cape Verde, off the coast of West Africa.

The storm intensified into a category four hurricane, before weakening and then intensifying again into a category five hurricane, about 1.000 kilometres further east than any hurricane of that magnitude has ever appeared before. Luckily Lorenzo decreased in strength again before skirting the Azores and continued to weaken before its extratropical remnants hit Ireland on October 3.

Lorenzo was category 5 on the Saffir-Simpson Scale

A category five hurricane is the highest, and therefore the most destructive, according the Saffir-Simpson hurricane wind scale, which groups hurricanes according to their effects. A category five hurricane has wind speeds equal to or higher than 252km/h, sustained over one minute.

The highest winds that were produced by Lorenzo were around 260km/h. While passing over the Azores, it produced winds of 163 km/h at Corvo Island, where schools and government offices were closed, and people were forced to remain indoors. Despite being over 3.200 kilometres from the storm, four people in North Carolina two people in New York sadly died after being swept away by rip currents caused by Lorenzo.

How is climate change affecting hurricanes?

Most hurricanes form in the west Atlantic and tend to affect areas around the Gulf of Mexico and the Caribbean islands before making their way inland or out into the Atlantic. As hurricanes need warm water to power themselves, they lose strength when they move inland or over the Atlantic. This causes them to dissipate into areas of low pressure or an extratropical cyclone - defined as a low-pressure front, capable of causing any kind of weather, from cloudiness to heavy rain to blizzards.

This usually stops hurricanes from hitting Europe, but it does sometimes happen. In 2005, Hurricane Vince hit southwestern Spain. While climate sceptics may dismiss this as a one-off, the increasingly warmer waters in the eastern Atlantic mean that storms can start forming further east and travel eastward for longer.

Researchers at the Royal Meteorological Institute of the Netherlands predicted in 2013 that hurricanes could become more prevalent in Western Europe in the future, especially if sea temperatures continue to rise. 

When Lorenzo formed, the Atlantic was around one degree warmer than usual. Anders Levermann from the Potsdam Institute for Climate Impact Research, near Berlin, explains that, “if the Atlantic is less cold, the storms will last longer on the way to the east, which increases the likelihood that they will reach Europe.” This could then lead to a regular hurricane season in Europe.