This year’s record-breaking Atlantic hurricane season officially ended Nov. 30, but the procession of violent storms it unleashed foreshadows a dark future fueled by climate change.
A combination of warmer oceans, weather patterns triggered by La Nina and an unusually busy African monsoon season led to the 30 tropical storms and hurricanes that formed in 2020—more than double the long-term average. A record 12 hit the U.S., and 10 abruptly exploded in strength and became more deadly as they approached land, which Yale Climate Connections meteorologist Jeff Masters says could be a grim omen for what lies ahead.
“We have entered a new climate,” Masters said. “Heat is energy and when everything else comes together and you get that heat there, then things are going to go bonkers.”
Total number of Atlantic storms per year, 1950–2020 ?
The year produced so many storms that forecasters exhausted the names on the official list and had to resort to the Greek alphabet to designate new ones. That’s only happened once before, in 2005, and 2020 went much further into the roster.
One of the drivers this year has been La Nina, the Pacific Ocean pattern that can affect weather around the world. It grew stronger than expected, shutting down wind shear across the Atlantic that can stop storms from growing, said Phil Klotzbach, lead author of the Colorado State University seasonal hurricane forecast.
Hurricanes draw their strength and power from warm ocean temperatures, and 2020 had the highest average sea surface temperatures on record.
With storms able to hold more moisture in a warmer climate and sea-levels rising, people along the coasts in the U.S., Mexico, the Caribbean and Central America are facing increased risks from Atlantic storms, said Katherine Klosowski, vice president and manager of natural hazards at insurer FM Global.
Related: Hurricanes Are Becoming Turbocharged—and Harder to Predict