The past three years were progressively the hottest years on earth. Worldwide, 2016 was the hottest ever. The Bureau of Meteorology described 2016 as a “year of extreme events” and the fourth hottest at 0.87 degrees Celsius above the 1961-1990 average.

According to NASA, the average global temperature for 2016 was 0.99 degrees Celsius hotter than the 20th-century average.

And it’s only getting hotter. January 2017 was the hottest ever in Australia. Given the current heatwave conditions across most of the continent this weekend - February is heading the same way.

Australia is heating up and drying out as the country experiences more extreme and prolonged heat events, according to the Bureau of Meteorology and CSIRO’s biennial State of the Climate report, released last October.

While it found higher instances of extreme events such as torrential rain and flooding, it also showed the average rainfall between May and July has decreased by about 19 per cent since 1970 in the southwest of the country. There has also been a decline of around 11 per cent in April to October rainfall in the country’s southeast since the mid 1990s.

The CSIRO said the latest report illustrated that the trends of climate change are very much continuing down under.

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“Climate change is happening now, it’s having a tangible impact on Australia,” the Bureau of Meteorology’s climate monitoring manager Karl Braganza told news.com.au.

The report also shows 15 of the 16 hottest years on record happened in the past 15 years.

“Australia has warmed up most notably since the mid-20s century,” says Dr Braganza.

“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.”

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.

While Western Australia had a cooler than average year in 2016,some parts of the giant state did hit 50 degrees, Australia’s observation of such heat a first in two decades.

Queensland has probably seen the least variation in its already hot climate: 2016 was one of its 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 2014’s Natural Resource Management report, 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.

*This report originally was published in 2015 and has been updated.