We’ve never seen this many named storms in a single year before. Subtropical Storm Theta just set another record for 2020.

• Subtropical storm Theta, which formed on Monday, is the 29th named storm of 2020.
• That’s more named storms than in any other year in recorded history. 
• As climate change causes air and ocean temperatures to rise, hurricanes are getting stronger. 
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As far as storms go, Subtropical Storm Theta isn’t particularly grand or threatening.

The storm formed in the Atlantic Ocean on Monday night, hundreds of miles off the coast of West Africa. Its maximum sustained wind speeds are about 70 mph — enough to do some damage on land, but shy of hurricane status. It’s too early to tell whether it will make landfall anywhere, and the National Hurricane Center hasn’t issued any warnings or watches. 

But Theta will go down in the history books anyway, because its formation means that 2020 has broken the record for most named storms of any year in recorded history. 

Previously, Hurricane Eta — which formed over Halloween weekend — put 2020 at a tie with 2005’s record. That year, there were 27 named storms, plus one storm that was strong enough to get a name but didn’t because scientists identified it after the season ended. (Storms are named once their wind speeds reach at least 39 mph.)

A year of unwanted climate records

The other storm currently moving through the Atlantic, Tropical Storm Eta, weakened after making landfall as a Category 4 hurricane on November 3 in Nicaragua. Eta was this year’s 12th hurricane, making 2020 the year with the second-highest number of hurricanes ever. Only 2015, with 15 hurricanes, had more, though 1969 and 2010 also had 12.

Eta also made 2020 the first year on record that three major hurricanes formed in the Atlantic between October and November. That's usually a time of year when storms tend to weaken as oceans cool and winds pick back up. Only four other hurricanes on record have reached Category 4 status in November, the most recent being Hurricane Paloma in 2008.

The 2020 hurricane season has surpassed researchers' most dramatic forecasts. In August, the National Oceanic and Atmospheric Administration predicted that the season would have up to 25 named storms and 11 hurricanes. With a month still to go, 2020 has seen four more named storms and one more hurricane than the forecasters expected.

Most of the year's named storms also came earlier than their counterparts in previous years. Hurricane Isaias, for example, formed on July 30 — the earliest storm with an "I" name on record. (Storm names go in alphabetical order.) Storms with "I" names don't usually form until October 4. Of the 29 named storms so far in 2020, only three – Arthur, Bertha, and Dolly – weren't the earliest with their letter to form in history.

Climate change leads storms to intensify more quickly

The next decade is expected to see even more active hurricane seasons, largely due to climate change. 

Research shows that climate change makes storms slower, stronger, and more devastating, since hurricanes feed on warm water. A single-degree Fahrenheit rise in ocean temperature can increase a storm's wind speed by 15 to 20 miles per hour, according to Yale Climate Connections.

Each new decade over the last 40 years has brought an 8% increase in the chance that any given tropical cyclone will become a major hurricane (Category 3 or above), according to a study published in May.

Similarly, a study from 2013 found that for each degree the planet warmed over the previous 40 years, the proportion of Category 4 and 5 storms  increased by 25% to 30%.

Warmer water can also lead storms to develop into powerful hurricanes more quickly via a process called rapid intensification. Eta was the ninth storm to rapidly intensify this year, and one of the fastest-intensifying storms on record. Such speedy intensification for a storm is unusual, especially in November. 

"It's more likely that a storm will rapidly intensify now than it did in the 1980s," James Kossin, an atmospheric scientist at NOAA, told the Associated Press in October. "A lot of that has to do with human-caused climate change."

A quickly intensifying storm not only poses a more severe threat to coastal areas, it also makes the event harder to predict and prepare for.

When a storm rapidly intensifies, it "does not appear to be a significant threat until it's too late, greatly stressing any preparation and evacuation plans," University of Miami atmospheric scientist Brian McNoldy told USA Today in August. "Neither human forecasters nor computer models do a great job with rapid intensification; it is one of the key challenges in all of meteorology."