How hot was 2020? Record-breaking heat is just the start as NASA warns it is ‘precursor of more to come’
By most accounts, 2020 has been a rough year. Now a new analysis suggests that it was also the hottest year on record, barely exceeding the record set in 2016 by less than a tenth of a degree. But since the margin is very narrow, NASA has determined that 2020 ties with 2016 as the warmest year on record, sharing the first-place spot.
“Earth’s global average surface temperature in 2020 tied with 2016 as the warmest year on record. Continuing the planet’s long-term warming trend, the year’s globally averaged temperature was 1.84 degrees Fahrenheit (1.02 degrees Celsius) warmer than the baseline 1951-1980 mean. 2020 edged out 2016 by a very small amount, within the margin of error of the analysis, making the years effectively tied for the warmest year on record,” explains NASA.
Researchers note that tracking global temperature trends provides a critical indicator of the impact of human activities – specifically, greenhouse gas emissions – on the planet. Earth’s average temperature has risen more than 2 degrees Fahrenheit (1.2 degrees Celsius) since the late 19th century.
Human-produced greenhouse gas emissions are largely responsible for warming our planet, they say. Burning fossil fuels such as coal, oil and natural gas releases greenhouse gases – such as carbon dioxide – into the atmosphere, where they act as an insulating blanket and trap heat near Earth’s surface.
“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,” says Gavin Schmidt, a climate scientist and the director of NASA’s Goddard Institute for Space Studies (GISS) in New York City.
According to scientists, massive wildfires that scorched the US’s west coast, Australia, and Siberia, intense hurricanes, and ice loss in 2020 are direct consequences of human-induced climate change.
Climate change has led to longer fire seasons, as vegetation dries out earlier and persistent high temperatures allow fires to burn longer. Heatwaves and droughts added fuel for the fires, setting the stage for more intense fires in 2020. For example, hundreds of wildfires burned throughout the western US this past year, making it the most active fire season on record.
Fires in Colorado grew quickly as heatwaves enabled the fire to burn faster and hotter. In California, over 650 fires were actively burning in late August. The largest of these – the August Complex Fire – burned over a million acres.
Overall, the US was hit with a record number of major disasters in 2020, costing billions of dollars and resulting in 262 deaths. “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,” said Lesley Ott, a research meteorologist at NASA’s Goddard Space Flight Center in Greenbelt.
Wildfires, hurricanes, and ice loss are projected to escalate into the next decade – especially if human-induced greenhouse gas emissions continue at the current rate. “This isn’t the new normal. This is a precursor of more to come,” warns Schmidt.
NOAA calls 2020 the second hottest
An independent analysis by the National Oceanic and Atmospheric Administration (NOAA) has concluded that 2020 was the second-warmest year in their record, behind 2016, thus knocking 2019 down to third hottest. Scientists from Copernicus also have 2020 tying with 2016 as the warmest year on record, while the UK Met Office ranked last year as the second-warmest on record.
“NOAA scientists use much of the same raw temperature data in their analysis but have a different baseline period (1901-2000) and methodology. Unlike NASA, NOAA also does not infer temperatures in polar regions lacking observations, which accounts for much of the difference between NASA and NOAA records,” explains NASA.
It adds, “Like all scientific data, these temperature findings contain a small amount of uncertainty – in this case, mainly due to changes in weather station locations and temperature measurement methods over time. The GISS temperature analysis (GISTEMP) is accurate to within 0.1 degrees Fahrenheit with a 95% confidence level for the most recent period.”
The average land and ocean surface temperature across the globe in 2020 was 1.76 degrees Fahrenheit (0.98 degrees Celsius) above average — this was the second-highest among all years in the 1880-2020 record, just 0.04 degrees Fahrenheit (0.02 degrees Celsius) cooler than the 2016 record. The Northern Hemisphere saw its hottest year on record at 2.30 degrees Fahrenheit (1.28 degrees Celsius) above the 20th-century average.
“A total of 103 named storms occurred around the world in 2020, tying the record number seen in 2018. The North Atlantic played an unusually large role in the global activity in 2020, accounting for about 30% of the global accumulated cyclone energy (ACE) and named storms — which is more than twice its usual share,” write experts.
December 2020’s average temperature across global land and ocean surfaces was 1.40 degrees Fahrenheit (0.78 degrees Celsius) above the 20th-century average, making it the eighth-warmest December in the 1880-2020 record.
7 warmest years have occurred since 2014
The world’s seven warmest years have all occurred since 2014, with 10 of the warmest years occurring since 2005. The year 1998 is no longer among the 10 warmest years on record, currently ranking as the 11th-warmest year in the 141-year record. 2020 was also Earth’s 44th consecutive year, since 1977, with global land and ocean temperatures, at least nominally, above the 20th-century average.
“The last seven years have been the warmest seven years on record, typifying the ongoing and dramatic warming trend. Whether one year is a record or not is not really that important – the important things are long-term trends. With these trends, and as the human impact on the climate increases, we have to expect that records will continue to be broken,” says Schmidt.
The globally averaged land surface temperature for 2020 was 2.86 degrees Fahrenheit (1.59 degrees Celsius) above the 20th-century average — the highest among all years in the 141-year record and surpassing the previous record set in 2016 by 0.09 degrees Fahrenheit (0.05 degrees Celsius). The six highest global land temperature departures have occurred since 2015, with the 10 highest occurring since 2005.
The 2020 annual global sea-surface temperature was the third-highest on record at 1.37 degrees Fahrenheit (0.76 degrees Celsius) above the 20th-century average — only 2016 and 2019 were warmer. Record-high sea surface temperatures were observed across parts of the Atlantic, Indian and Pacific oceans.