Today NASA and NOAA dropped theirs annual analysis belong to global temperature: Last year tied with 2018 as the sixth hottest ever, but colder than 2020. A good sign, right? Yes, no. At least not.
“It’s easy to focus on that year-to-year change,” said Bridget Seegers, an oceanographer at NASA. “But it’s important to look at trends: the past eight years have been the eight hottest years on record.”
To calculate global temperatures, the two agencies take data from weather stations around the world, plus measurements taken from ships and buoys in the ocean. Other groups like Berkeley Earth, a nonprofit research organization, do the same with their slightly different methodology. But the analyzes were almost identical in their findings. As you can see in the chart below, comparing results from Berkeley Earth, NOAA, NASA and two other groups in Europe, the average global temperature may be lower in 2021 than it is in 2020, but it is still increasing.
One reason for cooler temperatures in 2021 could be due to La Niña, a cold stretch of water in the Pacific Ocean. It’s the product of strong trade winds that sweep across the ocean, pushing the top layer of water toward Asia, sending deeper, colder waters to the surface to fill the void. This in turn affects the atmosphere, for example change the jet stream over the United States and lead to more storms in the Atlantic Ocean. The sea itself cools things by absorbing heat from the atmosphere.
The Covid-19 pandemic may have an additional effect, but not in the way you think. As the world closes down in 2020, less emissions will enter the sky, including Aerosol usually reflects some of the sun’s energy back into space. “If you take them away, you make the air cleaner, it’s a mild climate impact,” said Gavin Schmidt, director of NASA’s Goddard Institute for Space Studies. But as economic activity picks up again in 2021, aerosol pollution also contributes again to that cooling effect. The 2021 drop in temperatures “could be due to continued activity that produces atmospheric aerosols,” Schmidt said.
NASA data on temperature rise over decades
Illustration: NASA / NOAA(Based on the pandemic reduce carbon dioxide production has no cooling effect. Human civilization generates so much planet-heating gas each year, and it stays so long in the atmosphere, that the pandemic doesn’t even register as a blip.)
