2020 ties record for the hottest year ever, NASA analysis shows

The year 2020 — which saw the continuing coronavirus pandemic as well as massive wildfires across Australia, Siberia and the United States — also tied the record for the hottest year on record, a new NASA study shows.

Up until this past year, 2016 ranked as the warmest year on record for planet Earth. 2020 surpassed this previous record by a very small amount, under one-tenth of a degree, the agency announced Thursday (Jan. 14). However, the difference between the two years is within the margin of error, NASA officials added, making them effectively a tie.

"This year has been a very striking example of what it’s like to live under some of the most severe effects of climate change that we've been predicting," Lesley Ott, a research meteorologist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, said in a second NASA statement

Related: New climate study shows that we need to be patient 

COVID-19 effects

This news comes hot on the heels of findings that lockdown efforts early in the COVID-19 pandemic in 2020 temporarily reduced atmospheric nitrogen dioxide emissions. However, while "lockdown showed that we can change and change fast," Piers Forster, study co-author and director of the Priestley International Center for Climate at Britain's University of Leeds, told AFP in 2020, "it also showed the limits of behavior change … Without underlying structural change, we won't make it," he said, referring to climate goals. 

Additionally, "we still increased [atmospheric] carbon dioxide by two parts per million last year," Gavin Schmidt, climate scientist and director of NASA's Goddard Institute for Space Studies in New York City, told Space.com during a media teleconference Thursday as part of the 101st American Meteorological Society Annual Meeting. 

So, Schmidt said, these temporary changes in emissions "aren't going to have a direct effect on this year." But, he added, "the changes in aerosols and short-lived pollutants may ... and I think we'll see some more peer-reviewed literature on that."

More: Shutdowns from coronavirus create blue skies in California

Humans to blame

These record-setting temperatures are a result of human-produced greenhouse gas emissions, which largely come from burning fossil fuels like coal, oil and natural gas. Burning these nonrenewable resources creates carbon dioxide, which builds up in the atmosphere and traps heat. 

"The natural processes Earth has for absorbing carbon dioxide released by human activities — plants and the ocean — just aren't enough to keep up with how much carbon dioxide we’re putting into the atmosphere," Schmidt said in the NASA statement. 

This process of global warming will only continue as our species continues to produce and emit greenhouse gases like carbon dioxide and methane. In fact, carbon dioxide levels have increased by about 50% since the Industrial Revolution 250 years ago, and methane levels in the atmosphere have more than doubled in that span, according to the same NASA statement. 

Current climate models predict that, as the planet continues to get warmer over time, we will experience more heat waves, which will cause more droughts and wildfires (which we saw plenty of in 2020), more intense hurricane seasons, rising sea levels from melting ice sheets and more. 

Climate consequences 

In one of many consequences of these rising temperatures, the Arctic saw a serious heat wave in 2020. Summer temperatures soared above 100 degrees Fahrenheit (38 degrees Celsius) in Siberia, and the widespread heat in the Arctic even caused a wildfire outbreak. 

This wildfire outbreak reignited something known as "zombie fires," which were observed in the Arctic in 2019. Zombie fires can happen when fires burn in areas with permafrost, or carbon-rich soil that can stay frozen year-round. These fires can burn so intensely into a layer of permafrost that they can last even through a winter season under a blanket of snow, only to be revealed in the spring. 

Additionally, other dangerous wildfires were sparked in 2020, as climate change continues to lengthen fire seasons with local vegetation drying out in higher temperatures. Over 20% of Australia's temperate forest biome burned in 2020, according to the NASA statement, and the continent additionally saw fire-induced pyrocumulonimbus thunderstorms, powered by clouds that form above a severe wildfire. Smoke plumes from these fires reached a whopping 18 miles (30 kilometers) into the stratosphere.

As devastating natural disasters like these continue with growing temperatures, melting ice around the globe continues to add to rising sea levels and other consequences. While 2020 didn't set any records in terms of sea or land-based ice loss, Earth continues to lose about 13.1% of Arctic sea ice by area every decade, according to the NASA statement.

A small discrepancy

Though NASA's calculations peg 2020 as effectively tied with 2016 for the hottest year on record, analyses by researchers with the U.S. National Oceanic and Atmospheric Administration suggest that 2020 was actually slightly cooler than 2016. 

"The NASA data shows 2016 and 2020 very close together, though, in the NASA data, 2020 is slightly ahead," Schmidt said during Thursday's media teleconference. 

"But the differences between those years in both cases are actually well within the margins of error that we have for the uncertainty in these annual numbers," he added.

"We're all basically using the same raw data," Schmidt said. The different teams are just "stitching it together slightly differently," he added.

Email Chelsea Gohd at cgohd@space.com or follow her on Twitter @chelsea_gohd. Follow us on Twitter @Spacedotcom and on Facebook.

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Chelsea Gohd
Senior Writer

Chelsea “Foxanne” Gohd joined Space.com in 2018 and is now a Senior Writer, writing about everything from climate change to planetary science and human spaceflight in both articles and on-camera in videos. With a degree in Public Health and biological sciences, Chelsea has written and worked for institutions including the American Museum of Natural History, Scientific American, Discover Magazine Blog, Astronomy Magazine and Live Science. When not writing, editing or filming something space-y, Chelsea "Foxanne" Gohd is writing music and performing as Foxanne, even launching a song to space in 2021 with Inspiration4. You can follow her on Twitter @chelsea_gohd and @foxannemusic.