NASA announced Thursday that, globally, 2020 was the hottest year on record.
Technically, 2020 edged out 2016 by a very small amount, within the margin of error of the analysis, making the years effectively tied for the hottest year on record.
Overall, Earth’s average temperature has risen more than 2 degrees Fahrenheit since the 1880s. NASA says in its report, “Temperatures are increasing due to human activities, specifically emissions of greenhouse gases, like carbon dioxide and methane.”
The record warmth fueled deadly heatwaves, droughts, intense wildfires and other environmental disasters around the world in 2020. This global warming phenomenon is causing things like loss of sea ice, sea-level rise, longer and more intense heatwaves, and shifts in plant and animal habitats.
“The last seven years have been the warmest seven years on record, typifying the ongoing and dramatic warming trend,” said Goddard Institute for Space Studies Director Gavin Schmidt in a news release. “With these trends, and as the human impact on the climate increases, we have to expect that records will continue to be broken.”
The largest source of year-to-year variability in global temperatures typically comes from the El Niño-Southern Oscillation (ENSO), a naturally-occurring cycle of heat exchange between the ocean and atmosphere.
While the year has ended in a La Niño (a negative or cool phase of ENSO), it started in a slight El Niño (positive or warm phase), which marginally increased the average overall temperature.
The cooling influence from the negative phase is expected to have a larger influence in 2021 than 2020.
It’s a bit surprising that 2020 matched 2016, because 2016’s record warmth was fueled by El Niño, which tends to supercharge global temperatures.
NASA measures Earth's temperatures from land, air, and space with a fleet of satellites, as well as airborne and ground-based observation campaigns. NASA’s analysis incorporates surface temperature measurements from more than 26,000 weather stations and thousands of ship and buoy observations of sea surface temperatures.
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