Hurricanes have become a symbol for climate change and a rallying call for action. That’s especially the case since 2005, when Hurricane Katrina barreled into Louisiana and breached New Orleans levees, leaving behind an official death toll of 1,833.
Scientists found little evidence that climate change played any role in the wind speed intensity of Katrina, as well as Hurricane Irma in 2017 or Hurricane Maria in 2017, but they did pin increases in rainfall in those storms on climate change, according to the United Nations’ Intergovernmental Panel on Climate Change report released in August 2021.
Katrina in particular became a symbol of dysfunction and failing infrastructure—and raised awareness for the need to adapt to a new climate reality.
Nearly 20 years later, scientists still debate how climate affects hurricanes but they know a lot more, as they get better at the science of what they call “event attribution,” or the linking the causality of individual weather events to climate change.
As NASA puts it, “Earth’s atmosphere and oceans have warmed significantly in recent decades. A warming ocean creates a perfect cauldron for brewing tempests” because “hurricanes are fueled by heat in the top layers of the ocean.”
In the last quarter century, NASA has tracked the largest stretch of high energy hurricanes on record. “So while there aren’t necessarily more Atlantic hurricanes than before, those that form appear to be getting stronger, with more Category 4 and 5 events,” according to NASA.
In 2020, researchers from the National Atmospheric and Oceanic Administration (NOAA) and the University of Wisconsin found an 8 percent per decade increase in the odds that any tropical cyclone globally could become a Category 3 or higher, or those with wind speeds of 111 miles per hour or more. The study encompassed 39 years of storms.
That’s not all.
Oceans warm earlier, allowing storms to form before the official season begins, as happened in 2020’s record setting hurricane season with Tropical Storms Arthur and Bertha in May.
Hurricanes are intensifying faster and dropping more rain. Because of global warming, their destructive power persists longer after reaching land, increasing risks to communities farther inland that may be unprepared for devastating winds and flooding, according to research published in 2020 in the the journal Nature.
With rising sea levels, cyclones also push tidal waters further inland, making storm surges more dangerous and deadly.
With hurricanes being among the costliest of disasters, accounting for a record seven of 22 weather or climate disasters in 2020 that resulted in at least $1 billion in damages, humanitarian agencies are concerned.
There is a “general realization that we are facing a more challenging reality,” Maarten van Aalst, director of the International Red Cross and Red Crescent Climate Centre, which connects climate science with emergency response, told Inside Climate News.
—James Bruggers and Bob Berwyn