How climate change is fueling hurricanes
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[August 30, 2023]
By Gloria Dickie
(Reuters) - Hurricane Idalia's arrival on Florida's Gulf Coast due on
Wednesday signaled activity in the Atlantic's hurricane alley might not
be as quiet this year as meteorologists had once predicted.
Scientists initially forecast in May that the U.S. would see a
near-normal Atlantic hurricane season, but raised that forecast in
mid-August, projecting a more dangerous storm season.
That is because worldwide surface ocean temperatures have been
exceedingly warm this year, with temperatures in and around the Florida
Keys mirroring a hot tub this summer.
This, scientists said, may counteract the moderating influence of the El
Nino currently in effect, which typically reduces Atlantic hurricane
activity.
While scientists have not yet determined whether climate change is
influencing Idalia's strength or behavior, there is strong evidence that
these devastating storms are getting worse.
Here is why.
IS CLIMATE CHANGE AFFECTING HURRICANES?
Yes, 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.
![](http://archives.lincolndailynews.com/2023/Aug/30/images/ads/current/sunag_sda_FAIR_2023.png)
If it were not for the oceans, the planet would be much hotter due to
climate change. But in the last 40 years, the ocean has absorbed about
90% of the warming caused by heat-trapping greenhouse gas emissions.
Much of this ocean heat is contained near the water's surface. This
additional heat can fuel a storm's intensity and power stronger winds.
And this year is particularly bad.
Climate change can also boost the amount of rainfall delivered by a
storm. Because a warmer atmosphere can also hold more moisture, water
vapor builds up until clouds break, sending down heavy rain.
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%, according to an April 2022 study in the journal Nature
Communications.
![](http://archives.lincolndailynews.com/2023/Aug/30/images/ads/current/applegate_sda_FAIR_2023.png)
The world has already warmed 1.1 degrees Celsius above the preindustrial
average. Scientists at the U.S. National Oceanic and Atmospheric
Administration (NOAA) expect that, at 2C of warming, hurricane wind
speeds could increase by up to 10%.
NOAA also projects the proportion of hurricanes that reach the most
intense levels — Category 4 or 5 — could rise by about 10% this century.
To date, less than a fifth of storms have reached this intensity since
1851.
HOW ELSE IS CLIMATE CHANGE AFFECTING STORMS?
The typical "season" for hurricanes is shifting, as climate warming
creates conditions conducive to storms in more months of the year. And
hurricanes are also making landfall in regions far outside the historic
norm.
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![](../images/083023PIX/news_e7.jpg)
School teacher Roy Ross, 49, walks in a
flooded road after the passage of Storm Idalia in Playa Majana,
Cuba, August 29, 2023. REUTERS/Alexandre Meneghini
![](http://archives.lincolndailynews.com/2023/Aug/30/images/ads/current/atlantabank_quarter_FAIR_2023.png)
In the U.S., Florida sees the most hurricanes make landfall, with
more than 120 direct hits since 1851, according to NOAA. In recent
years, however, some storms are reaching peak intensity and making
landfall farther north than in the past – a poleward shift may be
related to rising global air and ocean temperatures, scientists
said.
This trend is worrying for mid-latitude cities such as New York,
Boston, Beijing, and Tokyo, where "infrastructure is not prepared"
for such storms, said atmospheric scientist Allison Wing at Florida
State University.
Hurricane Sandy, though only a Category 1 storm, was the fourth
costliest U.S. hurricane on record, causing $81 billion in losses
when it hit the Northeastern Seaboard in 2012.
As for timing, hurricane activity is common for North America from
June through November, peaking in September – after a summertime
buildup of warm water conditions.
However, the first named storms to make U.S. landfall now do so more
than three weeks earlier than they did in 1900, nudging the start of
the season into May, according to a study published in August in
Nature Communications.
The same trend appears to be playing out across the world in Asia's
Bay of Bengal, where since 2013 cyclones have been forming earlier
than usual - in April and May - ahead of the summer monsoon,
according to a November 2021 study in Scientific Reports.
It is unclear, however, if climate change is affecting the number of
hurricanes that form each year. One team of scientists recently
reported detecting a rise in frequency for North Atlantic hurricanes
over the last 150 years, according to their study published in
December in Nature Communications. But research is still ongoing.
HOW DO HURRICANES FORM?
Hurricanes need two main ingredients — warm ocean water and moist,
humid air. When warm seawater evaporates, its heat energy is
transferred to the atmosphere. This fuels the storm's winds to
strengthen. Without it, hurricanes cannot intensify and will fizzle
out.
CYCLONE, TYPHOON, HURRICANE - WHAT'S THE DIFFERENCE?
While technically the same phenomenon, these big storms get
different names depending on where and how they were formed.
Storms that form over the Atlantic Ocean or central and eastern
North Pacific are called "hurricanes" when their wind speeds reach
at least 74 mph (119 kph). Up to that point, they are known as
"tropical storms."
In East Asia, violent, swirling storms that form over the Northwest
Pacific are called "typhoons", while "cyclones" emerge over the
Indian Ocean and South Pacific.
(Reporting by Gloria Dickie in London; Editing by Marguerita Choy)
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