Warmer conditions in the oceans are raising the potential intensity for storms, where intensity refers to how bad they can get if nothing disrupts them. We have no clearer example of this than Hurricane Ida, a deadly and destructive hurricane that not only impacted the state of Louisiana but also parts of the Northeast US last week, where flooding in New York City caused the shutdown of most of the transportation system. When Ida made landfall initially in Louisiana, winds were blowing at 150 mph, tearing roofs off homes and ripping trees from their roots.
According to NOAA (National Oceanic and Atmospheric Administration), parts of the Gulf of Mexico are 3 – 5 degrees (Fahrenheit) higher than the average for the end of the 20th century. All the warm water in the ocean acts as “fuel” for hurricanes, much like gasoline is fuel to car engines. As Ida developed, it traveled over the hottest parts of the Gulf, using energy from the ocean to fuel its rapid growth in the form of clouds and high winds. With no upper atmospheric winds to disturb its growth, the hurricane began to churn faster and faster. As the storm got closer to shore, the sea surface temperature rose. Think about stepping on the accelerator of your car – flooring it. This is what the higher temperatures did to Ida. Barely 24 hours after it was identified as an unnamed tropical depression, Ida’s wind speeds reached 75 miles per hour — enough for the storm to be upgraded to a hurricane. After rapidly intensifying, Ida made landfall as a Category 4 hurricane on August 29th, the 16-year anniversary of Hurricane Katrina, the costliest storm on record in US history.
Climate change is setting the stage for bigger, faster and fiercer storms. Research shows that once-in-a-century intensification events – in which winds speeds accelerate to 70 mph in just 24 hours – could happen every 5-10 years by the year 2100 (http://texmex.mit.edu/pub/emanuel/PAPERS/Emanuel_BAMS_2017.pdf) Human-caused warming could leave to never-before-seen escalation of hurricanes. This is yet another warning from our planet. It’s not too late to mitigate the worst of these disasters, but we need to take swift and meaningful action.