The proof Australia is getting hotter

THERE’S no point in denying it: Australia is getting hotter, and it’s not going to stop. And we have the figures to prove it.

6.08AM The sun rises over Altona Pier as Melbourne prepares for a scorcher on a day of severe and extreme fire danger warnings. Picture: Mark Stewart

THERE is no point in denying it: Australia is getting hotter, and it’s not going to stop. And we have the figures to prove it.

Last year was the hottest year on earth. In Australia, it was the third hottest ever.

According to the World Meteorological Organisation (WMO), the average global temperature for 2014 was 0.57 degree warmer than the 1961-1990 average. In Australia, 2014 was ranked as the third warmest since records first began, dating back to 1910.

Combined with 2013 — ranked as the hottest year on record for Australia — we have experienced our warmest-ever 24 months, with prolonged heatwaves and hotter-than-average nights denying Australians some sought after, cool relief.

In Queensland, the town of Boulia has experienced 25 days of 40-plus temperatures - the longest heatwave ever. Western Australia had several days of near-50-degree heat this summer.

The Bureau of Metrology’s annual climate statement for 2014 backs up the WMO’s observations.

The CSIRO’s annual summary provided an equally damning report of Australia’s warming climate and goes further: predicting more extreme weather events, more extreme heat and fewer cooler extremes.

“Daytime maximum temperatures have warmed by 0.8°C [since 1910], while overnight minimum temperatures have warmed by 1.1°C,” the report stated.

In addition, since 2001, “the number of extreme heat records in Australia has outnumbered extreme cool records by almost 3 to 1 for daytime maximum temperatures and almost 5 to 1 for night-time minimum temperatures”.

Last year Australia’s average temperature was nearly 1 degree (0.91) above average.

All states — except for the Northern Territory — ranked 2014 in their top four warmest years on record, with New South Wales recording its hottest year to date — 1.41 degrees higher than the previous record set in 2009.

“Australia has warmed up most notably since the mid-20s century,” says Dr Karl Braganza, manager of climate monitoring at the Bureau of Meteorology.

“Prior to that, temperatures were reasonably flat — we didn’t have much of a trend.

“There was no clear trend prior to World War II — it’s from 1950 onwards that we’ve had a significant warming trend across Australia.”

How will it affect the states?

With hot days five times as likely to occur today as ever before, south-eastern states are, in particular, vulnerable to “a significant increase in fire weather across most of the fire-prone regions”, Dr Braganza says.

Combined with “a longer fire season and more frequent fire weather days”, Australia’s southern climate is primed for disaster, with rainfall steadily declining since 1970 in the southwest regions, across all seasons — most notably in autumn and early winter.

Dr Perkins says that heatwaves have become more intense in Victoria and South Australia, their force aided by lack of moisture in the air, a result of lower-than-average rainfall.

“Not having a lot of moisture in the air really does contribute to how a heatwave may occur. When you’ve just had rain, the heatwave won’t be very intense, if it occurs at all.

“But when you haven’t had much rain in the past six months, it’s a much higher likelihood that they have will be more intense.

“Hot, dry, weather and bushfires — there’s a good link there.”

Tasmania has also had a “warm and dry year” — with the state’s coldest months, June to September, experiencing temperatures well about their respective averages.

Although the effects of heatwaves are more profound in drier climates such as that of Victoria, South Australia and parts of New South Wales, north and northwest Australia have their own problems.

Western Australia, like NSW, recorded its hottest year on record in 2014, with statewide maximum temperatures the highest they have ever been. Current forecasts are showing that some parts of the giant state may even hit 50 degrees, Australia’s observation of such heat a first in 17 years.

Queensland has probably seen the least variation in its already hot climate: 2014 was its equal-third warmest year on record, with maximum temperatures reached 48 degrees in some parts of the state.

But Dr Perkins says while much of Queensland may not experience the same degree of heat intensity in summer as other, colder states, “Brisbane has been getting heatwaves in spring”

“They may not be having a heatwave in summer, but they’re having them a bit more in the spring, particularly after a dry winter.”

Global warming, she says, has increased the likelihood of heatwaves threefold, and “pretty much for any heatwave that’s happening, there’s some human signal behind it”.

Dr Braganza adds that warming both in Australia and around the world has been attributed mostly to increasing greenhouse gases, “which studies have shown is the likely dominant cause”.

The significance of heatwaves

In the last 60 years, Australia has warmed by one degree — a seemingly insignificant number that has huge ramifications.

Dr Braganza toldNews Corp Australia that “the warming has been accompanied by a shift in the distribution of daily weather, meaning that we are seeing a much higher frequency of extremely hot days and warm nights, and a much lower occurrence of very cold days and nights”.

Seasons are also slowly changing: whereas once, colder temperatures were common during much of spring, we are now seeing heatwaves such as the one in October last year last, which resulted in five consecutive days above 35 and averaged 40 degrees over five days in New South Wales alone.

An exceptionally warm May also saw temperatures soar across Australia, peaking in the mid-to-high 20s at a time when pre-winter cool should have been setting in.

Dr Sarah Perkins from the Climate Change Research Centre, an expert in heatwaves, says that “we’re definitely seeing more heatwaves” across Australia.

“Different areas are seeing different changes — some places may see an increase in the intensity of heatwaves, others in the duration.

“But the most pronounced change we are seeing is the number of heatwave days — so the number of days that belong in a heatwave each season — has been increasing since the 1950s.”

Broadly speaking, experts find it difficult to settle on a uniform definition of a heatwave, as “everyone has a different idea of what a heatwave is”.

While Dr Pekins broadly defines a heatwave as “three days in a row of temperatures in the top 10 per cent”, Dr Braganza says: “generally, you are looking for temperatures that are extreme for their location and extending across three or more consecutive days”. Taking into consideration the effect heat has on people’s health is also an important factor.

A terrifying future?

In the recently released Natural Resource Management report, updated for the first time since 2007, CSIRO and the Bureau have projected how the climate for Australian cities is likely to differ by 2030 and, subject to human action — or inaction — by 2090.

Using primarily two methods of measuring carbon emissions — high and moderate — the worst case scenario of each major city warming by at least 2.5 degrees by the end of the century is looking increasingly likely.

“At the moment, there’s a lot of climate inertia, and a certain amount of climate warming has already been locked in,” says CSIRO climate unit group leader Kevin Hennessy.

“So it now depends on human behaviour in the next couple of decades … because that could be the difference between a high emissions future and a low emissions future.”

By 2030, average temperatures will increase across all seasons for Melbourne (0.6); Adelaide (0.7); Brisbane (0.9); Canberra (0.8); Darwin (0.9); Hobart (0.6); Perth (0.8); and Sydney (0.9). That’s locked in, Mr Hennessy says.

Depending on what we choose to do about climate change from the middle of the century and beyond — “either accept that some of some amount of climate change in unavoidable and adapt and build resilience, or slow warming by reducing global greenhouse gas emissions,” says Mr Hennessy — some cities may become 4 degrees — or more — hotter, the heat bringing with it a plethora of problems, such as reduced water supply, draughts, the extinction of some flora and fauna and an increase in heat-related diseases and deaths.

Even by conservative measures, most cities will warm by at least 1.5 degrees by the end of the century, with some cities such as Canberra, Brisbane, Darwin and Sydney shooting up to nearly 4 degrees above the annual average.

In the worst case scenario, cities will flare up to 5 degrees above the 1986-2005 average, the soaring temperatures bringing destruction to Australia.

Originally published as The proof Australia is getting hotter