Milton .. Why have American hurricanes become more destructive?

Hurricane Milton struck the state of Florida in the United States as a Category 3 hurricane on Wednesday, October 9, with winds reaching speeds of 160 kilometers per hour, putting immense pressure on the coast still devastated by Hurricane Helen.

The situation remains a major emergency as several areas recorded heavy rainfall, prompting the National Weather Service to warn of flash floods, and power was cut off to more than two million homes and businesses in Florida.

The death toll from Hurricane Milton has not yet been announced, but on the other hand, Hurricane Helen was incredibly devastating, reaching Category 4 with winds of 210 kilometers per hour, causing massive floods, killing at least 45 people, and cutting off electricity to more than 4.5 million people in 6 states, with damages worth billions of dollars.

The risks are increasing.

Of course, that is hurricane season in that part of the world, but years ago, hurricane research centers recorded a new record, as it was the first time that two hurricanes with speeds exceeding 240 kilometers per hour came together. They were hurricanes Irma and Jose, which struck the Atlantic coast in October 2017.

Irma had set a new record by maintaining winds close to 300 kilometers per hour for over 65 consecutive hours, breaking a previous catastrophic record set by Hurricane Allen in Mexico, which lasted only 18 hours at peak intensity.

The number of Category 4 and 5 hurricanes—those with wind speeds exceeding 200 to 250 km/h—has increased from an average of 10 hurricanes per year in the 1970s to 18 hurricanes per year in the 1990s.
But why don’t hurricanes develop to become more powerful and destructive? Scientists believe that climate change plays a significant role in this matter.
Of course, it is not possible to determine whether a specific hurricane was affected by climate change, but overall, this seems to be what is happening.

This occurs in all regions affected by hurricanes worldwide, particularly in the northwestern Atlantic Ocean (the United States), the Caribbean Sea, and Central America, as well as the northwestern Pacific Ocean, including countries like Japan, China, and the Philippines, along with several other scattered areas bordering the world’s oceans.

3 factors

There are three main factors linking climate change to the intensity of hurricanes. The first is related to the rise in sea surface temperatures in the world’s oceans and seas. What connects it to hurricanes is simply that any hurricane draws its energy from that heat, using it to fuel its massive engine.

Therefore, it has become certain to us that as global average temperatures rise (the greenhouse effect), we become more susceptible to hurricanes, because ocean waters become hotter. This might explain the increasingly destructive impact of Hurricane Irma, which specifically originated in an area of the ocean where the surface temperature is one degree Celsius above average.

The second factor that intervenes in this relationship is related to rising sea levels. A study published in the journal “PNAS” indicates a close correlation between rising sea levels and the intensity and destructiveness of hurricanes in various locations.

This happens because rising sea levels allow hurricanes to push more water onto the shore during storms, leading to more severe flooding. With rising sea levels, the ocean absorbs more heat, and thus ocean temperatures rise.
This raises the rates of major hurricanes that occur at a rate of “once in a century” to “once every 10 years.” Additionally, with the encroachment of the sea and ocean on coastal cities, the danger of those shores being hit by catastrophic hurricanes increases significantly.

The third factor that contributes to increasing the potential for catastrophic flooding due to hurricanes is the rise in air temperature, as higher air temperatures can hold greater amounts of humidity. According to the “Clausius-Clapeyron equation,” the average humidity level increases by 3% with every 0.5-degree Celsius rise in temperature. This means an increase of more than 7% approximately for the current global situation, where the temperature has risen by more than one degree.

This increase in humidity levels means a similar rise in the amount of rainfall during the hurricane, which causes unprecedented floods.

Additional problems

In this context, scientists have observed a number of concerning phenomena. For example, hurricanes are now more prone to rapid intensification, meaning they can strengthen at a rate exceeding 56 km/h in less than 24 hours. This rapid intensification of hurricanes makes them more dangerous because it gives communities less time to prepare for severe conditions.

This phenomenon has become more common because warmer waters and favorable weather conditions provide an increase in energy, causing storms to develop into powerful hurricanes very quickly.

Recent studies indicate that hurricanes are moving more slowly than they used to, meaning they spend more time in one place, leading to more rainfall and prolonged flooding.

In addition, global warming affects wind patterns around the world, allowing for the formation of more hurricanes, increasing their strength, and prolonging their duration.

With the rise in global temperatures, the hurricane season starts earlier than usual and lasts longer, giving storms more time to form and strengthen.

In the end, although research teams may differ in the strength of this factor or that in influencing hurricanes, they all agree that hurricanes are stronger primarily because the oceans have become warmer due to climate change, along with the atmosphere. This poses an increasing threat to coastal communities and requires better planning and adaptation strategies to mitigate potential impacts.