Heatwaves and the Winter Solstice


Graph by The Conversation/BOM refers to the situation in Australia)

As the Winter Solstice came and went and our wood heater consumed the last of 2020’s firewood, the US mid-west was  sweltering through an early summer heatwave.

Australia is, hopefully, at least five months away from its first hot spell. But in the US mid-west states, which have been in the grip of the worst drought in 20 years, the mercury is rising. Cue Martha and the Vandellas..

Canadian relatives had already been posting photos on social media implying a very early summer, but across the border, things are grim.

The New York Times took the opportunity to conjure up an appropriate headline  “Climate change batters the west before summer even begins”.

In Arizona and Nevada, temperatures soared to 115F (46 Celcius), which would raise eyebrows even in Birdsville. Four writers contributed to a New York Times special report last weekend as Lake Mead, which supplies water to three south-western states and Mexico, fell to its lowest level since 1930. Early wildfires are burning in Utah, Montana and Arizona, while in California communities are debating water rationing.

In Texas, power utilities are pleading with customers to go easy on air conditioning in case excess demand causes blackouts.

Moreover, the June trend appears to have surfaced in some European countries, notably France. After a freak late-winter heatwave, above-average temperatures are assailing Europe.

Those with relatives living in the Northern Hemisphere will be hoping this does not signal a return to the disastrous heatwave conditions that killed 72,000 Europeans in 2003.

Not that we are immune in Australia, where it could be easy to argue that many of us live in heatwave-like conditions for at least three months of the year. At which point I should mention it seems to matter not if it is heat wave or heatwave.

It is difficult in winter to recall how it is to live through consecutive days with temperatures in the 40s. We should take our cue from the dog, who slinks off to the bathroom and splays himself on the cool tile floor.

Scientists agree (apart from those who don’t), that climate change is accelerating the severity and duration of heatwaves. Certainly in this country extreme hot spells increased markedly between 2000 and 2020.

Australia’s weather authorities have decreed a heatwave to exist when temperatures are seven degrees higher than average in any 30-day period. A report in November last year by Ralph Trancoso and others in Science Direct summarises highlights for Australia:

  • Future heatwaves could last up to a month should global temperatures increase by 1.5% to 3% in coming years.
  • There has been major increases in the 2000’s in comparison to previous decades;.
  • heatwaves have intensified in the recent past and are projected to increase faster in future;
  • heatwaves may be 85% more frequent if global warming increases from 1.5 to 2.0 °C.

In hindsight, perhaps we should have paid more attention during Australia’s ‘angry summer’ (December 2012-January 2013). The severity of the heatwave conditions then prompted a flurry of research reports on climate change.

Climate Council chief executive Amanda McKenzie chose the ABC’s Q&A forum in 2017 to claim that Australia’s heatwaves were worsening, with hot days doubling over the last 50 years.

The Conversation put this assertion to the test, asking the Climate Council, which had recently commissioned a report, for more detail.

Climate change is making hot days and heat waves more frequent and more severe,” a spokesperson said.  “Since 1950 the annual number of record hot days across Australia has more than doubled and the mean temperature has increased by about 1°C from 1910.

“”On average, that there are almost 12 more days per year over 35°C. 

Andrew King, Climate Extremes Research Fellow at the University of Melbourne, said there was not a large body of research against which to test these claims.

“But the research we do have suggests there has been an observable increase in the frequency and intensity of heatwaves in Australia. A review paper published in 2016 assessed evidence from multiple studies and found that heatwaves are becoming more intense and more frequent for the majority of Australia.”

In Australia, the general population is well versed in the art of remaining hydrated in hot weather. Regardless, heat-related deaths happen here, even though it is not often stated as such on death certificates.

UK academic Professor William Keatinge says few deaths are directly caused by heat-stress, although extreme heat exacerbates medical conditions including diabetes, kidney and heart disease.  Heat stress causes loss of salt and water in sweat, causing haemoconcentration, which in turn causes increases in coronary and cerebral thrombosis.

Other deaths in heatwaves are probably due to overload of already failing hearts, unable to meet the need for increased cutaneous blood flow in the heat.”

Writing in the British Medical Journal, Prof Keatinge said people at risk in heatwave conditions include those unable to sweat (because of diabetic peripheral neuropathy), or those taking anticholinergic drugs, barbiturates or phenothiazines, which depress reflex regulation of body temperature. Alcohol can also be dangerous in the heat, he added.

Meanwhile back in the relatively chilly southern hemisphere, Macca is due to deliver a load of ironbark firewood on Saturday morning. Even though nights have been cold here, apart from a few bleak days, it warms up to 19 or so by midday. Perfect weather to strip down to a t-shirt and jeans and shift the firewood to the shed around the back. The truth about cold snaps is you can always add another layer, crank up the wood fire or turn on electric heaters. The only real damage is to the power bill.

We do not have the same choices when weather phenomena like a heat dome pushes ‘normal’ summer temperatures to the levels usually experienced in arid places like Marble Bar or Coober Pedy (for America, read Death Valley).

The reappearance of heatwaves this summer will see a renewed focus by climate change activists on the Australian government’s inaction on climate policy.

And it’s official: Australia’s Prime Minister Scott Morrison has been formally rebuffed by the UK government, which is hosting a climate summit in Glasgow. Britain’s foreign secretary said Australia’s PM did not meet the required terms for attendance in November. The UK urged Australia to do more to reduce its carbon emissions.

It is illuminating, then, to revisit January 2020, when we were in the midst of catastrophic bushfires and a heatwave.

Mr Morrison told the media his policies on reducing emissions would ensure a “vibrant and viable economy, as well as a vibrant and sustainable environment”.

At the time, the United Nations had rebuked Australia, saying there had been no change in its climate policy since 2017. Emission levels for 2030, it said, were projected to be well above the target. The Climate Change Performance Index ranked Australia last out of 57 countries responsible for more than 90% of greenhouse gas emissions on climate policy.

Complicating matters now is the re-emergence of controversial politician Barnaby Joyce as Deputy Prime Minister. The conservative politician can fairly be described as a climate change denier. In 2012 he opposed the Labor government’s attempts to bring in a carbon pricing regime. Joyce was quoted in the SMH as claiming it would push the cost of a Sunday roast to $100. Infamously responding to public criticism of the Coalition’s environmental policies, he accepted the climate was changing, but insisted the solution was to respect God.

Heatwave? What heatwave?

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