Mar 1, 2019 - Science

Australia shatters record for its hottest summer

Bushfire during Australia's hottest summer on record.

A bushfire in Australia in late November 2018. Photo: Rob Griffith/AFP/Getty Images

Australia's scorching and widespread heat waves throughout this summer propelled the national average temperature to a new all-time high for the season, according to its weather bureau.

Why it matters: Australia is one of the countries most impacted by climate extremes, suffering from heat waves, bushfires and coral bleaching events tied to long-term, human-driven increases in greenhouse gas concentrations. However, this summer brought unprecedented heat to every part of the country — part of a trend consistent with what scientists predict as global warming continues.

Details: Typically, seasonal records are set by small margins. However, this summer's heat obliterated the past record for the hottest summer. The national mean temperature for the summer of 2018-19 was 2.14°C, or 3.8°F, above the 1961-90 average, according to Australia's Bureau of Meteorology (BOM).

  • The mean maximum temperature for the summer and the mean minimum temperature also broke all-time records.
  • The summer was the warmest on record for the states and territories of New South Wales, Victoria, Western Australia, and the Northern Territory.
  • Heat waves this summer were "unprecedented in size and scope," BOM stated.
  • The record heat was accompanied by numerous damaging wildfires, particularly in Victoria and New South Wales.

The big picture: The BOM points out that the summer of 2018-19 comes on the heels of "a string of warm months and seasons for Australia." In a seasonal summary, the agency states, "This pattern is consistent with observed climate change."

  • "Temperature records are likely to continue to be broken in the coming years," BOM added.
  • Australia's climate has warmed just over 1°C, or 1.8°F since 1910, "leading to an increase in the frequency of extreme heat events."
  • Oceans around Australia have warmed by nearly the same amount since 1910, "contributing to longer and more frequent marine heat waves."
  • In addition, the length and severity of the fire season has increased "across large parts of Australia," the report found.

By the numbers: Numerous all-time heat records were broken across Australia this summer. Here are some of the most noteworthy:

  • 35.9°C, or 96.6°F: The overnight low temperature on Jan. 17 in Noona, New South Wales, which was the country's hottest nighttime low on record.
  • 40°C, or 104°F: The temperature reached or exceeded in Canberra for 4 consecutive days, something that had not occurred since records began there in 1939.
  • 49.3°C, or 120.74°F: High temperature in Marble Bar, Australia, which was the highest temperature for anywhere in Australia in 2018.
  • 44.1°C, or 111.3°F: Average monthly temperature in Marble Bar during December, a new national record for the month.
  • 40.19 °C, or 104.3°F: Average daily maximum temperature for Australia on Dec. 27, which was the hottest December day on record for the country.

The bottom line: Numerous climate studies have tied increasingly persistent, frequent and severe heat waves to human-caused global warming.

  • A study published in 2017, for example, found a fingerprint of climate change in heat milestones worldwide. The study found that climate change has boosted the odds of record-breaking heat across more than 80% of the surface area of the globe for which reliable observations were available, including Australia.
  • Specific extreme event attribution studies need to be carried out before more conclusive links can be made to this summer's heat in Australia, but it fits national and global trends.

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