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Federal climate scientists say 2021 was sixth warmest year on record

In the Beaufort Sea off the coast of Alaska, global warming is melting sea ice and glaciers at an historic rate.
David Goldman AP
In the Beaufort Sea off the coast of Alaska, global warming is melting sea ice and glaciers at an historic rate.

An annual analysis of global temperatures released Thursday showed 2021 continued the decades-long trend of global warming.

The report comes from the federal agencies National Oceanic and Atmospheric Administration, NOAA, and the National Aeronautics and Space Administration, NASA. The study showed that atmospheric temperatures last year made it the sixth warmest year on record.

“But the more important point is that the past seven years have been warmer than anything we’ve seen over the past century,” said Russell Vose, chief of the climatic analysis branch of NOAA.

“Each of the past four decades has been warmer than the decade that preceded it. We are probably warmer than anything we’ve seen in the past 2,000 years, at least.”

Federal climate scientists say 2021 was sixth warmest year on record

Graphs released by NOAA show ups and downs in yearly temperatures within the framework of global warming.

And 2021 was slightly cooler than 2020. Vose said that may seem counterintuitive, since 2020 was a year of societal lockdowns, due to COVID-19, which closed factories and kept more people off the roads.

But he said the reduction in greenhouse gas emissions in 2020 came with a reduction of particulate air pollution, which allowed more sunlight to reach the planet's surface.

“If the factories aren’t running they’re not putting out these little particles called aerosols, which tend to reflect sunlight, and if they’re not there we’re just a tad bit warmer as a result of COVID than we would have otherwise expected,” said Vose.

Air temps.PNG
Courtesy NOAA/NASA
NOAA/NASA graph shows La Nina conditions was one reason 2021 was slightly cooler than 2020.

The federal report provided examples of real events like damaging cyclones in the Philippines and wildfires in the American west that are fed by rising temperatures. There are many examples of animal migrations, in which certain species journey north or uphill, in search of cooler temperatures.

“Like last year one of the stories I told was that the armadillos are moving into western North Carolina. We never saw them before but over the past decade or so you see armadillos,” said Vose, who lives in Asheville, NC.

Maybe the best indication of global warming is the temperature of the oceans, which absorb 90% of the globe’s excess heat. Last year set a new record for the oceans’ heat content. So did the year before that and the year before that.

“The ocean covers most of the globe, and it contains most of the energy in the climate system, by far,” said Alexander Gershunov, meteorologist at the Scripps Institution of Oceanography.

“That’s the energy available for hurricanes, various extreme weather events like marine heat waves,” he said. “This is the energy that’s available to erode the glaciers and ice sheets.”

Ocean temps.PNG
Courtesy NOAA/NASA
NOAA/NASA research graph shows heat content of the ocean set another record last year.

Gavin Schmidt is NASA’s director of the Goddard Institute for space studies, who also presented the annual report on global warming. Asked what could be done to stop the progress of global warming, he just encouraged people and societies to do all they can.

“Temperatures will keep rising as long as we increase the amount of greenhouse gases in the atmosphere,” he said. “And so mitigation efforts that are directed toward reducing greenhouse gases, or increasing their absorption, are things that can make a difference … every little bit counts.”