How climate change is fueling hurricanes

After a calm start to the season, Hurricane Fiona slammed into Puerto Rico and then hit the Dominican Republic, leaving more than a million people without running water or electricity.
Although scientists have not yet determined whether climate change has influenced Fiona’s strength or behavior, there is strong evidence that these devastating storms are getting worse.
Here’s why.
Does climate change affect hurricanes?
Yes, climate change is making hurricanes wetter, windier, and altogether more intense. It is also proven to slow the spread of storms, which means they can dump more water in one place.
Without the oceans, the planet would be much warmer due to climate change. But over the past 40 years, the ocean has absorbed about 90% of the warming caused by emissions of heat-trapping greenhouse gases. Much of this ocean heat is contained near the surface of the water. This extra heat can fuel the intensity of a storm and fuel stronger winds.
Climate change can also increase the amount of rain delivered by a storm. Because a warmer atmosphere can also hold more moisture, water vapor builds up until the clouds break up, sending heavy rain.
During the 2020 Atlantic hurricane season – one of the most active on record – climate change increased hourly precipitation rates in hurricane-force storms by 8% to 11%, according to a study by April 2022 in the journal Nature Communications.
The world has already warmed 1.1 degrees Celsius above the pre-industrial average. Scientists from the US National Oceanic and Atmospheric Administration (NOAA) expect that at 2°C of warming, hurricane wind speeds could increase by up to 10%.
NOAA also predicts that the proportion of hurricanes that reach the most intense levels – Category 4 or 5 – could increase by about 10% this century. To date, less than a fifth of storms have reached this intensity since 1851.
If not, how does climate change affect storms?
The typical hurricane “season” is changing, as global warming creates conditions conducive to storms for several months of the year. And hurricanes are also affecting regions well outside the historical norm.
In the United States, Florida sees the most hurricanes make landfall, with more than 120 direct hits since 1851, according to NOAA. But in recent years, some storms have peaked and made landfall farther north than in the past – a poleward shift could be linked to rising global air and ocean temperatures, scientists have said. .
This trend is concerning for mid-latitude cities such as New York, Boston, Beijing and Tokyo, where “the infrastructure is not prepared” for such storms, said atmospheric scientist Allison Wing of Florida. State University.
Hurricane Sandy, although only a Category 1 storm, was the fourth costliest US hurricane on record, causing $81 billion in losses when it hit the northeast coast in 2012.
In terms of timing, hurricane activity is common in North America from June through November, peaking in September – after a summer accumulation of warm water conditions.
However, the first named storms to make landfall in the United States now do so more than three weeks earlier than in 1900, pushing the start of the season into May, according to a study published in August in Nature Communications.
The same trend appears to be happening around the world in the Bay of Bengal in Asia, where cyclones since 2013 have been forming earlier than usual – in April and May – before the summer monsoon, according to a November 2021 study. in Scientific Reports.
It is unclear, however, whether climate change affects the number of hurricanes that form each year. A team of scientists recently reported detecting an increase in the frequency of North Atlantic hurricanes over the past 150 years, according to their study published in December in Nature Communications. But the 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 winds of the storm to strengthen. Without it, hurricanes cannot intensify and will die out.
Cyclone, typhoon, hurricane, what’s the difference?
Although technically the same phenomenon, these large storms are given different names depending on where and how they formed.
Storms that form over the Atlantic Ocean or the central and eastern North Pacific are called “hurricanes” when their wind speed reaches at least 74 mph. Until then, they are known as “tropical storms”.
In East Asia, violent, swirling storms that form over the Pacific Northwest are called “typhoons”, while “cyclones” emerge over the Indian Ocean and South Pacific. —Reuters