Wednesday, June 1, 2016

Australia's record Autumn temperatures: 1.86C temperature anomaly

The latest Climate Council report has outlined that Australia has set new record temperatures for Autumn 2016. This is to be expected given the strong El Nino this year, but it comes on escalating yearly global average temperatures from climate change.

According to the Climate Council report, Australia experienced its warmest March, second warmest April and second warmest May on record.

The Bureau of Meteorology said that autumn 2016 is the warmest autumn on record for Australia with the mean temperature anomaly exceeding 1.86 °C - the largest anomaly for any season since spring 2014 when it was 1.67 °C. They argue that while El Niño and other climate drivers were a factor in warmer temperatures, "it is the background trend which now largely explains the more frequent high temperature records."

If you thought it was a tad warm in Sydney, Darwin, Canberra and Brisbane during April, you would be correct. Nearly every day in April was above average in these cities.

Globally March and April this year were the warmest on record, with May likely to follow this trend.

It was particularly warm in Sydney with the average maximum temperature for the first half of May at 24.3°C, almost 5°C above the monthly average.

On the 17th of May, only two weeks from the start of winter, inner-Sydney temperatures reached 28.2°C, warmer than the average maximum temperature for January.

The Bureau of Meteorology reports that a prolonged heatwave at the beginning of March saw Australia observing its hottest March day on record at 38.14 °C on 2nd March. Other Australian temperature records for the season include:
  • Australia’s warmest autumn for mean temperature (1.86 °C above average)
  • Australia’s warmest autumn for mean minimum temperature (1.87 °C above average)
  • Australia’s largest positive mean temperature anomaly for any season (surpassing +1.67 °C set in spring 2014)
  • Australia’s warmest March for mean (+1.70 °C) and minimum (+1.97 °C) temperatures
  • Australia’s second-warmest twelve-month period with an anomaly of +1.28 °C (behind +1.31 °C during November 2012– October 2013).
  • Australia’s warmest March day(s), recorded on three consecutive days (the 1st (37.51 °C), 2nd (38.14 °C) and 3rd (37.59 °C) of the month)
  • Australia’s warmest May night, recorded on 7 May of 16.96 °C, surpassing the previous warmest recorded on 14 May 1958 of 16.81 °C

There were also many state records set. It was Queenland’s warmest autumn for mean temperature (2.35 °C above average). Similarly, New South Wales’ warmest autumn for mean temperature (2.21 °C above average). Victoria saw its warmest autumn for mean temperature (1.88 °C above average). The Northern Territory experienced its warmest autumn for mean temperature (2.21 °C above average).

Night temperatures were also elevated for Autumn. The bureau of Meteorology reports in special climate statement 56 (PDF):

Nights were exceptionally warm throughout the season. Minimum temperatures were above or very much above average for nearly all of Australia (Figure 2). Autumn minima were highest on record for large areas of the Northern Territory, northern Western Australia, northern South Australia, much of Queensland, the southern half and central areas of Victoria and almost all of Tasmania. About 29% of Australia recorded the highest autumn mean minimum temperature on record. The autumn national mean minimum temperature was +1.87 °C above average. State mean minimum temperatures for autumn were highest on record in Queensland, Tasmania and the Northern Territory, and second-highest on record for New South Wales and Victoria.

Australia is now experiencing above 1 degree of global warming, and while El Nino is a factor, The Bureau of Meteorology assesses that it is the underlying global warming trend that is largely now responsible for the record temperatures being experienced. Here is how the Bureau describes it:

Australia's climate has warmed substantially in recent decades, and continues to warm. The total warming evident in autumn mean temperatures are slightly more than one degree above average. Natural climate variations such as El Niño now occur on a much warmer mean temperature state. Entering the 2015–16 El Niño, temperatures over Australia were already much warmer than the previous El Niño events.

Elevated ocean sea surface temperatures

The Australian region also experienced record sea surface temperatures in March and April.

Ocean temperatures off the east coast of Australia have remained well above average from the Coral Sea to off the coast of Tasmania. This has resulted in 93 per cent of coral reefs bleached, with some 35 per cent coral mortality. Off Tasmania's coast a marine heatwave devastated the aquaculture industry throughout early Autumn.

Scientific analysis has shown that human caused climate change made the extreme ocean temperatures that led to 93 percent of coral bleaching along the Great Barrier Reef this year at least 175 times more likely.

The huge problem is that climate change temperature projections means that extreme March ocean temperatures that caused this year’s event occur every two years during March by the mid-2030s. At that rate corals are simply unable to recover and we are likely to see extinction of coral reefs played out over the coming decades.

Politicians offering token funding to Great Barrier Reef water quality management when the Reef is facing extinction fails to acknowledge the dire nature of the problem. It is a climate emergency.

It is clear that Coal-fired power stations must be phased out, and quickly, and that renewable energy scaled up rapidly to meet the challenge of climate change. But we also need to tackle our export coal problem. And we need to treat the situation with the appropriate level of seriousness. We are already in a climate emergency and the energy of government, business and individuals needs to be focussed on transition to 100 per cent renewables zero carbon economy.

Here is the last word from the Climate Council and their Autumn report:

The number of climate records that continue to tumble is further evidence that our climate is changing rapidly and with serious impacts. The window of time that we have to limit the global temperature rise is closing. With every year of delay, the job gets tougher and the likelihood of avoiding many of the worst impacts of climate change becomes more remote. To meet the commitments that we made just a few months ago in Paris, we must urgently get on with the job and join the global transition to a clean energy world.


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