Global warming pushed temperatures to near-record levels in 2020, in effect tying 2016 as the hottest year on record, according to data released Thursday by U.S. science agencies.
Last year’s average global surface temperature was 2.2 degrees Fahrenheit above the late 19th century average, according to NASA. It was the fifth consecutive year of more than 2 degrees above that base line.
Indeed, the seven hottest years in 140 years of record-keeping were the last seven. In descending record order, they are 2020 and 2016, 2019, 2017, 2015, 2018 and 2014.
Chart showing the global surface temperatures. 2016 and 2020 are the hottest years.
The fact that the planet’s average temperature reached such heights — absent the short-term warming effect of El Niño — reveals the unmistakable signal of human-caused greenhouse gas emissions, researchers said. It also shows the ever-increasing dominance of these emissions as global warming continues to accelerate.
“It’s a testament to the power of the long-term trends,” said Gavin Schmidt, a climate scientist at the NASA Goddard Institute for Space Studies, who worked on the analysis.
The alternating cycle of El Niño and La Niña in the Pacific Ocean, which repeats roughly every five years, has long been the biggest natural driver of year-to-year fluctuations in the Earth’s temperature. A strong El Niño can boost global temperatures by about 0.4 degree.
The previously undisputed hottest year, 2016, started off with a powerful El Niño that helped boost temperatures that entire year.
Zeke Hausfather, a climate scientist with the nonprofit research organization Berkeley Earth, which conducted an independent global temperature analysis that came to similar conclusions, said it is “startling” to see 2016-level warmth in the absence of El Niño.
“It shows that five years of human CO2 emissions can have nearly as large an impact on global temperatures as a super El Niño event, and reinforces the fact that our emissions are what is driving the rapid warming of the planet over the past few decades,” Hausfather said.