There wouldn’t be weather without heat; heat is energy, and weather is an expression of that energy, of an atmosphere trying to balance itself. But too much heat in the system raises the limits of what is possible in weather and pushes it toward the extremes.
So it’s maybe no surprise then that this year’s record heat was a “through line” in many of 2023’s most brutal weather events, Kristina Dahl, climate scientist with the Union of Concerned Scientists, told CNN.
“Climate change influences our weather on Earth every day,” Dahl said. “In my mind, the burden of proof now is to show that climate change hasn’t influenced an event, because it’s just so clearly influencing everything around us.”
The extreme weather events of this year are not unique – they’re a sign of what’s to come.
“These types of events will continue to become more frequent and more severe if we continue to warm the planet,” Dahl said.
These are just a few of 2023’s most notable examples of what a warming planet’s extreme weather can look like.
Off-the-charts rapid intensification
Record heat wasn’t just in the air, it made it to the oceans too, which absorb most of Earth’s excess heat.
“Sea surface temperatures were just so much warmer than they have been in any previous year on record,” Dahl said.
Warm water acts like food for storms, and the exceptionally warm ocean water in 2023 not only created more storms in the Atlantic by neutralizing the storm-dampening effects of a strengthening El Niño, but also fueled explosive strengthening of the storms that formed across the globe.
This explosive strengthening, known as rapid intensification, is becoming more likely as the atmosphere warms.
Lee was the strongest Atlantic hurricane this season and maxed out as a rare Category 5 hurricane in the open ocean in September after its winds strengthened by a staggering 85 mph in 24 hours. The outburst made Lee the Atlantic’s third-fastest rapidly intensifying storm on record.
The storm briefly reached Category 4 status before slamming Florida’s Big Bend region as a Category 3 hurricane – the strongest storm to hit there in more than 125 years.
The East Pacific’s Hurricane Otis was the most extreme example of rapid strengthening in either basin this year. Otis’s winds increased by an astounding 115 mph in the 24 hours before its devastating Category 5 landfall in Acapulco, Mexico, in October.
Otis was the strongest Pacific storm to ever strike Mexico and came just two weeks after Category 4 Hurricane Lidia – also a rapid intensifier – made landfall just south of Puerto Vallarta as another one of Pacific Mexico’s strongest storms.
Rapid intensification also helped Hurricane Hilary maintain enough strength to track across California as a tropical storm – the state’s first since 1997. Hilary unloaded a deluge that broke tropical rainfall records in a few states and caused extreme flooding that lingered for months in one of the driest places on Earth.
A historic tragedy in a year of unusual wildfire behavior
Unusual wildfire behavior marked the year, both in where fires started and where they didn’t.
Wildfires typically burn 7 to 8 million acres of land each year in the US, but only charred 2.6 million acres in 2023, National Interagency Fire Center statistics show.
This was due in part to a soaking start to the year in the typically fiery West, which kept wildfires to a minimum after years of destruction. One season a trend does not make, and as the world warms, wildfires are becoming more frequent and severe – particularly in the West, the latest National Climate Assessment notes.
Still, the season proved deadly and destructive as intense heat combined with a lack of rain to dry out soil and leave typically wet parts of the US and much of Canada vulnerable to fire.
Tragedy struck Hawaii’s island of Maui in August in the form of the blazing Lahaina inferno.
Wind-driven flames surged so quickly through drought-parched invasive grasses, engulfing everything in their path, that some people fleeing for their lives had no choice but to jump into the Pacific Ocean. Many could not escape, and the Lahaina Fire became the deadliest on US soil in more than 100 years.
Louisiana is one of the wettest states in the US, but after a summer of endless heat, no tropical systems and little rain, the ground turned to tinder. The tremendous dryness peaked in November when 75% of the state was under exceptional drought – the most expansive such area in state history.