The gargantuan bushfires across Australia continue to rage. They’ve burned at least 17.9 million acres, destroyed more than 3,000 homes, and killed at least 28 people since September. The choking smoke from these blazes is causing a health crisis and has literally circled the world. At the Australian Open in Melbourne this week, Slovenia’s Dalila Jakupovic forfeited her match after keeling over as smoke from the wildfires permeated the tennis stadium and made it difficult for her to breathe.
Awful scenes in Melbourne.
— ESPN Australia & NZ (@ESPNAusNZ) January 14, 2020
Australia’s bushfires and the conditions behind them are alarming and unprecedented, but not unexpected. Australia is warming faster than the global average due to climate change, and parts of the country are getting drier.
The blazes got going in 2019, which the Australian Bureau of Meteorology has now confirmed was the country’s hottest and driest year on record. This rising heat and aridity helped create the conditions for the massive blazes torching the country.
However, climate change is pummeling Australia on top of its notoriously volatile weather that can bring jarring shifts year to year, or even in the same year. That’s a big reason Australia is so vulnerable to extremes and why the continent is experiencing some of the world’s worst climate-related disasters.
“It’s always been a variable continent in terms of weather,” said Mark Howden, director of the Climate Change Institute at the Australian National University. “What we saw last year and are seeing this year to date I think both reflect that historical variability but with added components chucked in because of climate change, and that’s generated temperatures well beyond what we have seen before.”
As the climate changes, the swings in temperature and precipitation are poised to become more vast and frequent. While many of the factors that are driving the vacillating patterns of temperature and rainfall are unique to Australia, other parts of the world may soon face their own volatile weather. So it’s important to understand how it occurs and how it’s changing in the land down under.
Why Australia’s weather is so erratic
Several factors contribute to Australia’s notoriously shifty climate. Australia’s landmass is large enough to include climate regions from the tropics in the north to deserts in the middle to temperate regions in the south.
The continent is also situated between the Antarctic, Indian, and Pacific oceans. Along Australia’s coasts, these oceans act like buffers and help moderate the climate in cities like Sydney. But Australia is a continent, which means it experiences continentality, a phenomenon where inland areas far from water experience a wider temperature range than the coasts.
That’s not to say that oceans don’t influence the middle of Australia. The surrounding bodies of water undergo periodic changes in water and atmospheric circulation patterns: El Niño, the Indian Ocean Dipole, the Southern Annular Mode, and so on.
Depending on the phase of their cycles, these patterns can bring torrential rains, searing heat, high winds, or cool breezes. When several patterns align, they can easily push weather toward extremes, particularly in the middle of the continent. That’s a big reason Australia has the most variable rainfall of any continent, explained Howden.
“When we get a wet year in Australia, it’s actually detectable in terms of the sea level rise across the globe because there can be so much water sitting on the continent that you can actually lower the sea level a little bit,” Howden said.
Another factor in Australia’s weird weather is that it doesn’t have a large inland system of lakes and rivers. Some large lakes can form during periods of torrential rain, but those lakes aren’t very deep, which means they don’t store much heat and can evaporate quickly. That reduces their capacity to cushion surrounding regions against temperature extremes.
Australia also doesn’t have a large, snow-capped mountain range like other continental landmasses. Melting mountain snow can act as a reservoir for water throughout the year and keep rivers and lakes topped up. For Australia, this makes inland areas more dependent on rainfall and more vulnerable to drying out in droughts than areas that do have white peaks to supply water.
Together, these elements leave many parts of Australia ping-ponging between deluges and droughts as well as heat and cooler air.
Australia’s extreme heat and drought in 2019 was building for years. Researchers saw it coming.
In 2008, economist Ross Garnaut was commissioned by Australia’s Commonwealth, state, and territory governments to look at the potential climate change impacts to Australia’s economy, and his report was startlingly prescient.
“Recent projections of fire weather (Lucas et al. 2007) suggest that fire seasons will start earlier, end slightly later, and generally be more intense,” according to the Garnaut Climate Change Review. “This effect increases over time, but should be directly observable by 2020.”
More recently, the Australian government’s Bushfire & Natural Hazards Cooperative Research Center warned last August that the 2019-2020 fire season “has the potential to be an active season across Australia, following on from a very warm and dry start to the year.”
Compare the above forecast map to this January 14 NASA map of fires detected in Australia over the past seven days:
One of the main signals of the extreme heat and drought of 2019 emerged when the Indian Ocean Dipole, the temperature gradient between the eastern and western parts of the Indian Ocean, reached record strength. This pushed moisture away from Australia in the spring. There was also a bout of sudden stratospheric warming over Antarctica, also reaching record levels. This heated air over Antarctica was channeled toward Australia’s surface with the help of the Southern Annular Mode, a westerly band of wind circling Antarctica.
The hot, dry conditions in 2019 also came after Australia’s third winter in a row with very low precipitation. That means there was precious little water on the ground to soak up heat, allowing the landmass to get hotter and hotter.
It turned out that the middle of the continent absorbed so much heat that it overwhelmed the moderating influence of the oceans on the coasts. “What we saw recently was essentially the hot and dry interior impinging on the coasts because winds from the pressure systems were bringing that sort of hot, dry … central Australian air or Western Queensland air onto those coastal areas, and that’s part of the reason why we had such extreme fires,” Howden said.
Yet even in the country’s driest year ever, parts of Australia broke flood records “by a large margin” during storms in February, according to Australia’s Bureau of Meteorology.
The torrential rain hit farming regions in Queensland the hardest, killing an estimated 500,000 livestock animals. It shows that even a year of record-breaking drought can have pockets of extremes in the other direction.
How the weather down under is changing
Australia is also warming faster than the global average. Even with the backdrop of large annual variations in weather, distinct trends are emerging. Eight of Australia’s 10 warmest years have occurred since 2005, and the continent as a whole has warmed by more than 1 degree Celsius since 1910.
However, the changes not all in the same direction. “Rainfall has increased across parts of northern Australia since the 1970s,” according to the Bureau of Meteorology’s 2018 State of the Climate report. “There has been a decline of around 11 percent in April–October rainfall in the southeast of Australia since the late 1990s.”
As temperatures continue to rise, Australia is poised to experience more frequent and intense heat waves, as well as worsening fire weather, and the conditions the country experienced in 2019 are a sign of what’s in store.
“Temperatures in December in Australia that have occurred recently, they are extreme for now but they would be normal under a world getting on for three degrees of warming, so we are seeing a sign of what would be normal conditions under a future warming world of 3 degrees [Celsius],” Richard Betts, a researcher at the United Kingdom’s Met Office Hadley Center, told the BBC.
But these changes will not be slow and steady. Instead, Australia is likely to face even more volatility in its weather. For example, the State of the Climate report anticipates “[d]ecreases in rainfall across southern Australia with more time in drought, but an increase in intense heavy rainfall throughout Australia.”
That means that while overall precipitation may decline, when rainfall does occur, it will happen more as massive downpours, leaving the country bouncing between flooding and drought. It’s a phenomenon some scientists have called weather whiplash, and it shows how increases in annual average temperatures and rainfall can mask more dangerous changes underway.
The Bureau of Meteorology is particularly concerned with this increasing variability fueling compound extreme events. “As climate change continues, the combination of increases in heavy rainfall and rising sea levels means that coastal and estuarine environments may have an increase in flood risk from multiple causes,” according to the State of the Climate report.
Climate change is also shifting where and when ocean and atmospheric circulation patterns gather strength. That is changing the timing of the seasons in Australia, the location of major rainfall events, and wildlife habitats. The East Australian Current, for instance, shunts warm water south along Australia’s east coast. It’s a crucial mechanism for cycling nutrients and maintaining the ideal temperatures for the region’s unique sea life.
“Historically, it’s sort of departed and headed off to New Zealand out into the east roundabout Sydney latitudes,” Howden said. “But these days because of climate change, it’s often going down [south] to Tasmanian latitudes.” The change in current will force some marine ecosystems to relocate, but others may disappear as a result.
And while Australia is facing some of the most extreme weather in the world, other countries should pay attention because they may not be far behind.
“Particularly in southern Australia, it sort of maps relatively similarly over other areas in the mid-latitudes, what we’d think of as the Mediterranean zone. So it’s the Mediterranean proper, like Spain and Italy and Greece, but [also] California, the tip of South Africa, [and] over in Chile and Argentina,” Howden said. “So all of those latitudes around the same as Australia, they’re getting dry, are getting hotter, having more problems in terms of water, in terms of agriculture.”
The changes in climate and variability will make it difficult to plan for disasters and will increase the costs associated with events like Australia’s devastating fires. But they also have knock-on effects, such as declines in agricultural production, tourism, and health. While these shifts are poised to get worse, it’s also important to remember that they’re already taking a toll.
“We’re already starting to see these changes cut into things which we see as really important in Australia,” Howden said.