Last nine years all among Earth’s 10 hottest-ever, says US report

The past nine years rank among the 10 hottest on record, according to an annual report a US agency’s annual report.

Children cool off at the Children's Park in Buenos Aires on Thursday. Picture: AFP

The nine years spanning 2013-2021 all rank among the 10 hottest on record, according to an annual report a US agency released on Friday AEDT, the latest data underscoring the global climate crisis.

For 2021, the average temperature across global surfaces was 0.84C above the 20th-century average, making the year the sixth-hottest in the overall record, which goes back to 1880.

“Of course, all this is driven by increasing concentrations of heat trapping gases like carbon dioxide,” said Russell Vose, a senior climatologist for the National Oceanic and Atmospheric Administration.

“There’s probably a 99 per cent chance that 2022 will rank in the top 10, a 50-50 chance, maybe a little less, it’ll rank in the top five, and a 10 per cent chance it’ll rank first”, barring an unforeseen event like a major volcanic eruption or a large comet hitting Earth, he said.

Thursday saw mercury rise to 50.7C in the coastal town of Onslow in Western Australia, the country’s hottest day on record.

NOAA uses the 21-year span from 1880 to 1900 as a surrogate to assess pre-industrial conditions, and found the 2021 global land and ocean temperature was 1.04C above the average.

A separate analysis of global temperature released by NASA had 2021 tying with 2018 as the sixth-warmest on record.

Both data sets vary very slightly from the EU’s Copernicus Climate Change Service in their assessment, which had 2021 as the fifth-warmest in records tracking back to the mid-19th century.

But the overall convergence of trends increases scientists’ confidence in their conclusions.

Increases in abundance of greenhouse gases since the industrial revolution are mainly the result of human activity and are largely responsible for the observed increases.

Climate scientists say it is crucial to hold end-of-century warming to within a 1.5C rise to avert the worst impacts – from mega-storms to mass die-offs in coral reefs and the loss of coastal communities. At the present rate of heating, the planet might hit 1.5C in the 2030s. “But it’s not the case that at 1.4 everything is hunky dory and at 1.6 all hell has broken loose,” said NASA’S Gavin Schmidt.

The impacts have been increasingly felt – including record-shattering bushfires across Australia and Siberia, a once-in-1000-years heatwave in North America and extreme rainfall that caused massive flooding in Asia, Africa, the US and Europe. Last year also saw nearly 700 people die in the US due to extreme weather events, such as Hurricane Ida, and a maximum temperature in Sicily of nearly 49C, a European record if verified.

The heat records observed in 2021 came despite the year beginning in a cold phase thanks to an El Nino Southern Oscillation episode across the central and eastern tropical Pacific Ocean.

Heating might have also been partly offset by the resumption of activities that created heat-reflecting aerosols, which were lower during Covid-related lockdowns of 2020. The northern hemisphere land surface temperature was the third-highest on record. The 2021 southern hemisphere surface temperature was the ninth-highest on record. Land heat records were broken in parts of northern Africa, southern Asia, and southern South America in 2021, while record high sea surface temperatures were observed across parts of the Atlantic and Pacific oceans.

AFP