2021 Sixth Hottest Year on Record, Scientists Studying if Temperature Rise Is Speeding Up

Three United States scientific agencies reported 2021 was the sixth hottest year in recorded history, with some scientists worrying early signs are pointing to an acceleration in rising temperatures.

The National Oceanic and Atmospheric Administration (NOAA), Berkeley Earth and NASA all came to a similar conclusion in statements released Thursday. NASA determined 2021 was tied with 2018 as the sixth hottest year, while the other two organizations said 2021 was hotter than 2018.

According to its statement, scientists at NASA's Goddard Institute for Space Studies found that global temperatures in 2021 were higher than the agency's baseline temperature by 1.5 degrees Fahrenheit. NASA uses the period between 1951 and 1980 as its baseline.

NASA Administrator Bill Nelson said in the statement that eight out of the top 10 hottest years on record were in the last decade, calling it "an indisputable fact that underscores the need for bold action to safeguard the future of our country—and all of humanity."

"Science leaves no room for doubt: Climate change is the existential threat of our time," Nelson said. "NASA's scientific research about how Earth is changing and getting warmer will guide communities throughout the world, helping humanity confront climate and mitigate its devastating effects."

Berkeley Earth and the NOAA's data corroborates NASA's statement.

Zeke Hausfather, a climate scientist with Berkeley Earth, told the Associated Press to "give it a few more years" and humanity will see the next hottest year on record.

"It's the long-term trend, and it's an indomitable march upward," he said.

Gavin Schmidt, head of NASA's temperature team, expressed a similar sentiment to the AP in an interview, calling this long-term trend "very clear."

"If you just look at the last the last 10 years, how many of them are way above the trend line from the previous 10 years? Almost all of them," Schmidt was quoted by the AP.

According to the NOAA, 2021 was the 45th consecutive year of temperatures around the world going above the 20th century average. It also added that ocean heat content, or the amount of heat stored in the upper levels of the ocean, was at a record high, with the previous record being set in 2020.

Berkeley Earth's statement said annual temperature averages reached record highs in 25 countries including China, South Korea and Nigeria.

​​"No one lives at the global average temperature," Dr. Robert Rohde, Berkeley Earth lead scientist, said. "Most land areas will experience more warming than the global average, and countries must plan their responses to this."

In a statement, Dr. Kristina Dahl, a senior climate scientist with the Union of Concerned Scientists, said the scariest part about the findings is that they are "no longer surprising or shocking."

"Failure to act together with the global community will all but ensure more devastating impacts and even irreversible climate tipping points," Dahl said. "In 2022, we need bold leaders who prioritize the well-being of people and the planet, not incrementalism or regression from those beholden to the fossil fuel industry."

California, wildfire, climate change
Several U.S. agencies have found that 2021 was the sixth hottest year on record. Above, flames from the Alisal Fire chew through chaparral brush on October 13, 2021, near Goleta, California. Photo by David McNew/Getty Images