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Data released by National Aeronautics and Space Administration (NASA) shows that earth’s global average surface temperature in 2020 tied with 2016 as the warmest year on record.

According to a statement by NASA on Thursday, last year's global average temperature was 1.02 degrees Celsius (°C) or 1.84 degrees Fahrenheit (°F). Scientists at NASA’s Goddard Institute for Space Studies (GISS) in New York said this is a continuation of the planet’s long-term warming trend.
 
“The last seven years have been the warmest seven years on record, typifying the ongoing and dramatic warming trend,” said GISS Director, Gavin Schmidt. “Whether one year is a record or not is not really that important – the important things are long-term trends.”

Temperatures are increasing due to human activities, specifically emissions of greenhouse gases (GHGs), like carbon dioxide (CO2) and methane. Rising temperatures have caused climate change, resulting in various weather and climate disaster events around the globe. NASA said a warmer planet has caused phenomena such as loss of sea ice and ice sheet mass, sea level rise, longer and more intense heat waves, and shifts in plant and animal habitats.

Overall, the independent agency of the United States federal government said earth’s average temperature has risen more than 1.2°C (2°F) since the 1880s. The United Nations has said limiting global temperature rises to 1.5°C above pre-industrial levels by the end of this century would reduce the devastating effects of global warming.

According to NASA, data on long-term climate trends is essential for the safety and quality of human life. Understanding this would inform changes in human activities. It would enable humans in adapting to the changing environment in ways such as planting different crops, managing our water resources and preparing for extreme weather events.

“As the human impact on the climate increases, we have to expect that records will continue to be broken,” Schmidt added.  

The agency said a variety of events and factors contribute to any particular year’s average temperature. For example, two separate events changed the amount of sunlight reaching the earth’s surface last year. The Australian bush fires during the first half of 2020 burned 46 million acres of land, releasing smoke and other particles more than 18 miles high in the atmosphere, blocking sunlight and likely cooling the atmosphere slightly.

The record rise in earth’s global average temperature in 2020 happened regardless of global shutdowns put in place by governments to curb the spread of the ongoing COVID-19 pandemic. NASA said the shutdowns reduced particulate air pollution in many areas, allowing more sunlight to reach the surface and producing a small but potentially significant warming effect. These shutdowns appeared to have reduced the amount of CO2 emissions last year, but overall CO2 concentrations continued to increase. Warming, in any case, is related to cumulative emissions. Hence, the overall amount of avoided warming was minimal.

NASA also said a warm phase of the El Nino-Southern Oscillation (ENSO) – a naturally occurring cycle of heat exchange between the ocean and atmosphere – at the beginning of last year caused a marginal increase in the average overall temperature.

NASA’s analysis incorporates surface temperature measurements from more than 26,000 weather stations and thousands of ship- and buoy-based observations of sea surface temperatures. These raw measurements are analysed using an algorithm that considers the varied spacing of temperature stations around the globe and urban heating effects that could skew the conclusions if not taken into account. The agency uses a baseline period of 1951 to 1980 for the calculations of global average temperature difference.

A separate and independent analysis by the US National Oceanic and Atmospheric Administration (NOAA) shows that 2020 was the second-warmest year in their record, behind 2016. NOAA scientists use much of the same raw temperature data as NASA in their analysis, but they have a different baseline period (1901-2000) and methodology.