The past year, 2023, is officially the hottest on record. The global average temperature of 58.96 degrees Fahrenheit not only eclipsed the previous record holder—2016—by a third of a degree but was also a staggering 2.67 degrees warmer than the late 1800s pre-industrial baseline.
“It’s humbling, and a bit worrying, to admit that no year has confounded climate scientists’ predictive capabilities more than 2023 has,” wrote Gavin Schmidt, director of NASA’s Goddard Institute for Space Studies, in an article in the journal Nature. In May 2023, carbon dioxide concentrations in the atmosphere peaked at 424 parts per million at NOAA’s Mauna Loa Observatory, Hawaii. carbon dioxide concentrations are the highest they have been in at least 800,000 years.
The return of El Niño also played a significant role in the heat spike. The phenomenon weakened trade winds and warmed the sea surface temperatures in the central and eastern Pacific, a shift that often coincides with global temperature peaks. “For the most part, it’s us and El Niño,” said Josh Willis, a climate scientist at NASA’s Jet Propulsion Laboratory. “At the end of the day, humans are heating the planet, and El Niño is dancing on our heads.”
Global sea surface temperatures, too, reached new heights, contributing to the overall heat. The North Atlantic and other marine areas experienced several heatwaves, with the ocean absorbing approximately 90 percent of the heat trapped by greenhouse gases. The warming seas play a critical role in raising global temperatures.
Interestingly, while aerosols such as smoke, dust, and pollutants can reflect sunlight and cool the atmosphere, a decrease in these particles, due to improved air quality regulations, is believed to have had the opposite effect, contributing to the warming.
Michael Mann, Presidential Distinguished Professor in the Department of Earth and Environmental Science at the University of Pennsylvania, said the premise that 2023’s warmth cannot be explained—or that it is inconsistent with model simulations—is “simply wrong.”The situation is extremely similar to what we saw during the 2014–2016 period as we transitioned from several years of La Niña conditions to a major El Niño event, and then back to La Niña,” Mann said in an email.
Relevant articles:
– ‘Humbling, and a bit worrying’: Researcher claims that models fail to fully explain record global heat
– Five Factors to Explain the Record Heat in 2023, nasa.gov, Fri, 12 Jan 2024 08:00:00 GMT
– A sudden spike in global warmth is so extreme, it’s mysterious, The Washington Post, Fri, 13 Oct 2023 07:00:00 GMT
– Putting This Summer’s Record Global Heat Into Context, Columbia University, Thu, 07 Sep 2023 07:00:00 GMT