NASA Deems 2020 the Hottest Year in Recorded History

COVID-19 lockdowns temporarily reducing emissions in certain cities around the world wasn’t enough to reduce the global temperature in 2020. In fact, new NASA data found that 2020 was the hottest year on record, just barely edging out the previous record holder. 

Similar data from three other major agencies found that 2020 either tied for Earth’s hottest year on record, or came in as the second-hottest year on record. 

NASA’s Goddard Institute for Space Studies found that 2020’s average temperature very slightly edged out 2016’s, reporting 2020’s average temperature as 1.84 degrees Fahrenheit (1.02 degrees Celsius) warmer than the average. So even though NASA’s data technically determined 2020 to be the hottest year on record, the agency is classifying this slight difference in average temperature to be a tie.

Measuring the global average temperature for an entire year is no small task, so it makes sense that different agencies’ results may vary slightly. 

For instance, Copernicus’ Climate Change Service technically determined 2020 and 2016 a tie, though Copernicus technically found 2020 to be less than 0.01 degree Celsius cooler than 2016.

According to the National Oceanic and Atmospheric Administration (NOAA), Earth’s average land and ocean surface temperature in 2020 was 1.76 degrees Fahrenheit (0.98 degrees Celsius) above average, and the past year was just 0.04 degrees Fahrenheit (0.02 of a degree Celsius) cooler than 2016, which the NOAA classifies as the hottest year in recorded history. 

The NOAA also found 2020 to be the hottest year on record for the Northern Hemisphere, coming in at 2.30 degrees Fahrenheit (1.28 degrees Celsius) above average. Additionally, the NOAA found the global sea-surface temperature in 2020 to be 1.37 degrees Fahrenheit (0.76 degrees Celsius) above the average, making 2020 the third hottest year for oceans on record.

Unsurprisingly, the seven hottest years for planet Earth have all occurred between 2014 and 2020, the NOAA added, which really shows how the issue of global heating is persisting.

Data from the U.K. Met Office (compiled along with the University of East Anglia and the U.K. National Centre for Atmospheric Science) also found that 2020 was the second-warmest year on record.

The short answer: because of increasing greenhouse gases in the atmosphere, which are primarily due to human activity, such as drilling for fossil fuels, animal agriculture, and deforestation.

That said, there were a variety of specific events in 2020 that contributed to the year’s concerningly high temperatures. The Met Office cites humanity’s use of fossil fuels, as well as La Niña and El Niño conditions.

NASA cites two events that impacted how much sunlight reached the Earth’s surface: the Australian bushfires, which released smoke that actually blocked sunlight and may have slightly cooled the planet; and reduced atmospheric pollution as a result of coronavirus lockdowns, which let more sunlight hit the Earth’s surface, which led to an increase in temperatures.  

The Paris Climate Accord, aka the Paris Agreement, is a landmark treaty signed by nearly every country in the world, promising to work toward the agreement’s central goal: to keep this century’s global temperature rise below 1.5 degrees Celsius (2.7 degrees Fahrenheit) above pre-industrial levels. 

With the global temperature continuing to increase in 2020, this important goal is even more far off than before. As the Met Office notes, the Paris Agreement’s goals measure long-term averages, not single years — but still, we have a lot of work to do to meet these goals, and the new data about 2020’s average temperature highlights that.