A sizzling month marked by record heat waves, major wildfires, melting sea ice and a burgeoning El Niño will go down in the books as the hottest July on record — at least until next year, federal officials said Monday.
The planet and its oceans roasted last month as global average temperatures soared 2.02 degrees above average, making July 2023 not only the hottest July ever, but very likely Earth’s warmest month in at least 174 years of record keeping.
“Climatologically, July is the warmest month of the year,” the National Oceanic and Atmospheric Administration said in a monthly report released Monday. “As the warmest July on record, July 2023, at least nominally, was the warmest month on record for the globe.”
Temperature data through July make it virtually certain that 2023 will rank among the five warmest years on record, with a nearly 50% probability that it will be the single warmest year on record, the agency said.
The announcement came as little surprise to millions of Americans who suffered through extreme heat conditions firsthand.
The stubborn presence of a high-pressure heat dome over the American Southwest pushed temperatures in Phoenix to 110 degrees or hotter for a record 31 days straight. More than 40 deaths were recorded in the county with hundreds more under investigation, and scores of people were hospitalized for heat-related illnesses and pavement burns.
In Greece, Italy, Canada and Algeria, raging wildfires ignited amid broiling temperatures, spewing noxious smoke and sending residents and tourists fleeing for safety. Death Valley soared to 128 degrees, while areas in northwest China climbed as high as 126.
A multitude of factors converged to drive the sweltering conditions, said Karin Gleason, chief of the monitoring section at NOAA’s National Centers for Environmental Information.
The onset of El Niño, a climate pattern in the tropical Pacific, warmed areas around the equatorial Pacific, pushing land and ocean temperatures to new extremes. Surface temperatures simmered 0.36 degrees warmer than the previous July record, set in 2021.
Oceans also suffered from the heat, with July marking the fourth consecutive month of record-high global ocean surface temperatures.
At 1.78 degrees above normal, the month saw the highest monthly sea surface temperature anomaly of any month in NOAA’s climate record. Ocean temperatures off the coast of Florida rose to an unprecedented 101 degrees — roughly the temperature of a hot tub.
However, Gleason noted that El Niño is not solely to blame.
The pattern arrived after a rare three consecutive years of its counterpart, La Niña, which is known to have a cooling effect in some regions that may have been masking an ongoing warming trend, she said.
“Because we were in that prolonged La Niña period, there was this sense that the Earth wasn’t warming, when in reality, the rest of the ocean basins besides the eastern equatorial Pacific were warm, and were gradually warming,” Gleason said. “But now with those waters warming, it just shines a light on how warm the other ocean basins really have been.”
That larger warming trend is almost entirely attributable to human-caused climate change, said Daniel Swain, a climate scientist at UCLA.
