Last year stands alongside ’16 among Earth’s hottest on record
The year 2020 was either tied for the hottest on record or second hottest — an unwelcome distinction either way.
Two reports released Thursday by NASA and the National Oceanic and Atmospheric Administration, while measuring heat a bit differently, both show the planet was more than 1.7 degrees Fahrenheit warmer last year than the 20th century average, highlighting an unrelenting shift toward a hotter and less hospitable future.
The heat hit California head on. Last year Death Valley logged what might be the
world’s highest temperature in modern times: 130 degrees on Aug. 16. The wildfires brought even more pain. Infernos across the West were among 22 natural disasters in the United States in 2020 that NOAA identified as costing more than $1 billion each, an unprecedented number of such events, fueled at least partially by the warming.
Only 2016 rivals 2020 for record heat. The past six years, though, have been unquestionably the warmest since 1880, when the federal government began keeping tabs on average global surface temperatures.
“We’re telling you the same story about longterm change, even though we’re telling it in a different way,” said Russell Vose, chief of climate monitoring at NOAA’s National Centers for Environmental Information, who joined NASA officials in announcing the two climate reports. “There’s been a steady increase in temperature since the ’60s.”
The planet’s temperature across land and sea is now estimated to be about 2 degrees higher than it was in the 1800s. Under the Paris climate accord, world leaders have vowed to limit the warming to 3.6 degrees, or 2 degrees Celsius, since the 19th century. Scientists have warned that anything above that threshold could cause irreversible changes to the planet, resulting in more drought, flooding, extreme weather and other climate distress.
The economic slowdown last year brought on by the coronavirus pandemic put a lid on some of the industrial and vehicle emissions that are driving the heat. An analysis by the research company Rhodium Group this week cited a 10.3% dip in greenhouse gas emissions in the United States. Worldwide, many experts estimate a decline of 7% in 2020.
But the lull in pollution is likely to be shortlived, and scientists say much bigger reductions are needed to change the climate’s worrisome trajectory.
“The only way to get warming down to zero is to get emissions down to zero,” said Zeke Hausfather, a climate scientist at Berkeley Earth, an independent environmental research organization. “Even though we had a big drop in emissions last year, our emissions are still enormous.”
Berkeley Earth released its own analysis of 2020 global temperature data Thursday in tandem with the federal government. The group found last year to be the second warmest since 1850, though the level of uncertainty in the measurements left it in a virtual tie with the recordsetting 2016.
Similar to the federal reports, Berkeley Earth’s analysis showed California having its third warmest year on record, after 2014 and 2015 respectively. The United States as a whole had its fifth warmest year.
The report by NOAA pegged 2020 as the second hottest year worldwide. The NASA report found 2020 in a statistical tie with 2016. The difference is caused by the way agencies weigh temperature data collected across thousands of gauges at surface weather stations and on boats or buoys.
Other climate agencies around the globe, including the United Kingdom’s Met Office and the European Union’s Copernicus, have also determined that 2020’s average surface temperature ranked alongside 2016 ’s or was just slightly behind.
The agencies agree that Europe and Asia had their hottest years, and South America and the Caribbean had their secondhottest years. Fortyone countries experienced a record average temperature, according to the analysis by Berkeley Earth.
But nowhere was the heat so severe as at the Arctic, which is estimated to be warming three times as fast as the rest of the planet. The region saw a record 100.4degree day in northeastern Siberia in June, and half the sea ice across the continent is believed to have melted since the 1980s.
“It seems pretty clear that Arctic amplification is a very serious and dramatic consequence,” said Gavin Schmidt, director of NASA’s Goddard Institute for Space Studies.
While scientists expected last year’s average temperature to be well above the norm, many were surprised that it was as high as it was. Weather conditions in 2020 were marked by a La Niña weather pattern, a cyclical cooling of Pacific Ocean temperatures that often lowers temperatures worldwide. By contrast, 2016 experienced an El Niño, the opposite end of the ocean cycle, which helps increase temperatures.
“The fact that we have a modest La Niña year that is just as warm as a strong El Niño year really says something about temperature rise,” Hausfather said.
In light of the new temperature data, many of the world’s governments are calling for accelerated action to address climate change. Nations are scheduled to meet in Glasgow in November to discuss their progress cutting greenhouse gas emissions and hitting the targets of the Paris climate accord, which was signed in 2015.
Though President Trump has pulled the United States out of the international climate treaty, Presidentelect Joe Biden has pledged to put the country back in. Meeting the goals of the accord, however, will require big changes, including expediting the shift toward renewable energy and away from gasolinefueled cars.