Climate change is making cyclones more intense and destructive, say scientists

By | May 15, 2023

Climate change It doesn’t make cyclones like the one hitting Bangladesh more frequent, but it does make them more intense and destructive, according to climatologists and weather experts.

These extremely powerful natural phenomena have different names depending on the area where they strike, but cyclones, hurricanes, and typhoons are violent tropical storms that can produce 10 times more energy than the atomic bomb on Hiroshima. They are divided into different categories based on the maximum sustained wind power and the scale of the damage they can cause.

Cyclones, storms and hurricanes

“A cyclone is a low pressure system that forms in the tropics in an area that is warm enough to develop,” Emmanuel Clope of the French meteorological service Meteo France told AFP. “It is characterized by rain/storm clouds that begin to rotate and generate heavy rain and wind, as well as a wind-driven storm surge,” he added. These massive weather features, several hundred kilometers in diameter, are made more dangerous by their ability to travel great distances. Tropical cyclones are classified according to the intensity of their winds, ranging from tropical depression (less than 63 km/h), tropical storm (63-117 km/h) to major hurricane (more than 115 km/h).

They are called cyclones in the Indian Ocean and South Pacific, storms in the North Atlantic and Northeast Pacific, and hurricanes in the Northwest Pacific. The meteorological services that monitor them use different scales to categorize them, depending on the ocean basin in which they occur. The best-known scale for measuring its intensity and destructive potential is the five-point Saffir-Simpson wind scale.

more powerful cyclones

“The total number of tropical cyclones per year has not changed globally, but climate change has increased the occurrence of more intense cyclones and catastrophic storms”, according to the World Weather Report (WWA), a group of climatologists and climate impact experts whose goal is to demonstrate reliable links between global warming and certain weather events. The most violent cyclones – categories three to five on the Saffir-Simpson scale that cause the most damage – have become more frequent, WWA said. Climate change caused by human activity affects tropical cyclones in three main ways: by warming the air and oceans, and by causing sea level rise. “Tropical cyclones are the most extreme precipitation events on the planet,” says WWA in its Report on Extreme Weather and Climate Change.

Since the atmosphere is warmer, it can hold more water, so when it rains, it pours down. “An increase in air temperature of three degrees Celsius can potentially cause a 20% increase in the amount of rain produced by a cyclonic event,” Klopp said.

These heavy torrential rains trigger sometimes deadly flooding and landslides, as was the case with Cyclone Freddy, which killed hundreds of people in Malawi and Mozambique earlier this year. Climate change is also warming the oceans. This warm water feeds the cyclones and gives them their strength.

“Therefore, climate change is creating the conditions under which more powerful storms can form, rapidly intensify and persist to make landfall, while carrying more water,” WWA said.

switch north

The strong winds generated by cyclones create storm surges that can cause coastal flooding. These storm surges are now higher than in previous decades due to sea level rise caused by climate change. Scientists also expect to see cyclones in places they haven’t seen them before because global warming is expanding the areas where tropical seawater conditions occur. “It’s like the tropics are spreading out,” Klopp said.

“Areas that aren’t really affected now could be much more affected in the future.” WWA agreed: “As ocean waters warm, it is reasonable to assume that tropical storms will move further from the equator.” “The northward shift of cyclones in the western North Pacific, affecting east and southeast Asia, is a direct consequence of climate change,” she said. As a result, they could attack relatively unsuspecting places that they had no reason to expect in the past.

Source: AFP

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