20/01/2021

Annual Heat Records Tumble As Global Warming Trend Continues

Sydney Morning Herald - Miki Perkins

Was 2020 the record hottest year on earth or did it tie with 2016?

The answer lies in tiny differences in how scientific agencies collect data, but their results all reveal the same urgent reality: the past seven years on earth have been the hottest on record, a global warming trend that is driven by climate change and set to continue.

Data shows 2020 was a year of record temperatures. Credit: Getty

New temperature analysis from NASA reveals Earth's 2020 global average surface temperature effectively tied with 2016 as the warmest year on record, despite the cooling La Nina weather pattern.

The globally-averaged temperature last year was 1.02 degrees warmer than the NASA baseline (1951-1980) and edged out the record set in 2016 by a tiny amount.

Earth's average temperature has risen more than 1.2 degrees since the late 19th century, according to NASA.

"The last seven years have been the warmest seven years on record, typifying the ongoing and dramatic warming trend," said Gavin Schmidt, the director of the Goddard Institute for Space Studies at NASA.

NOAA: 2020 the second warmest year on record
Average 2020 temperature compared to the 1981-2010 average

Note: 0 degrees Fahrenheit is equivalent to -17.78°C. Source: NOAA climate.gov, NCEI

"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."

In a slight contrast, the National Oceanic and Atmospheric Administration (NOAA) has released its own results, which show the rise in temperature for 2020 was just 0.02 degrees shy of 2016's record.

NOAA scientists use much of the same raw temperature data in their analysis as NASA, but have a different baseline period (1901-2000) and methodology. Similarly the United Kingdom Met Office ranked 2020 as the second-warmest year on record.

Climate change is driving rapid global warming and worsening the impacts of natural variability, said Climate Council expert Will Steffen.

China has pledged to become carbon neutral by 2060. Credit: Getty
"Right now, we are on track for catastrophic climate change of 3 degrees celsius of heating and maybe more," Professor Steffen said.

"At just over 1 degree of heating, we are already paying a serious price, as we have seen with the recent Black Summer bushfires, prolonged drought and the third mass bleaching of the Great Barrier Reef in five years. 

"Year after year, decade after decade, temperature records continue to tumble because we continue to burn coal, oil and gas. It must stop."

In 2020, the Australian bushfires burned 46 million acres of land, and smoke and particles in the atmosphere blocked sunlight and probably cooled the atmosphere slightly, NASA's analysis found.
Year after year, decade after decade, temperature records continue to tumble because we continue to burn coal, oil and gas.
Professor Will Steffen
However, the agency also said global shutdowns from the COVID-19 pandemic reduced air pollution in many areas, allowing more sunlight to reach the earth's surface and producing small but potentially significant warming.

Overall, carbon dioxide concentrations continued to increase, and since warming is related to cumulative emissions, the overall amount of avoided warming will be minimal, according to NASA.

Professor Steffen said he was encouraged to see state and territory governments stepping up their climate commitments: "2021 needs to be a year of climate action because failure is not an option."

Land and ocean temperatures
Source: NOAA climate.gov, NCEI
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