While Australia battles record-smashing heat, interminable drought and deadly bushfires, the United States is in the grip of a polar vortex, with temperatures plunging to their lowest in history.

After Adelaide’s mercury soared to an unprecedented 46.6C last week, toppling a heat record from 1939, 12 people have died in freezing temperatures and heavy snow across America’s Midwest.

A nine-year-old died in a crash on Iowa’s icy roads, an 18-year-old college student was found dead on the University of Iowa’s campus, and a 75-year-old man was hit by a snow plough in Chicago as authorities warned of the danger of “instant frostbite”.

Schools, offices and colleges were closed across the region with temperatures on Lake Michigan plunging to an icy -29C on Wednesday local time.

Chicago was colder than Antarctica, Alaska and the North Pole on Wednesday, and set to break its -32C record from 1985 early on Thursday.

Australians, of course, have the opposite problem, with power failures causing misery in Victoria as air-conditioning use soars and households evacuating as bushfires rage across Tasmania.

Twelve bushfire warnings are in place for the state and the Huon Highway that connects Hobart to southern Tasmania is partially closed.

In the US, blizzard-like conditions across the Midwest saw 1700 flights cancelled in the Chicago area alone, the postal service suspending operations, and rail tracks set alight to keep trains moving.

Snow plough drivers in Wisconsin were struggling to deal with record snowfall. Sturgeon Bay was blanketed under 32.5cm — more than double its 1949 record — and Manitowoc saw 26.7cm snowfall, breaking a 1918 record of 18cm.

There is worse to come, with a blast of Arctic wind racing through Maryland and Baltimore City Health Commissioner Mary Beth Haller calling the temperatures “dangerously cold”.

Wind chill in northern Illinois could fall to a -48C, which the US National Weather Service called potentially “life threatening”, advising people not to drive or even leave their homes unless necessary.

Weather Prediction Center meteorologist Brian Hurley said Minnesota temperatures could hit -34C with a wind chill of -51C. “You’re talking about frostbite and hypothermia issues very quickly, like in a matter of minutes, maybe seconds,” he said.

Donald Trump caused controversy when he seized the opportunity to question how climate change could really be warming the planet if the weather was so abnormally cold. “What the hell is going on with global warming?” he joked. “Please come back fast!”

In the beautiful Midwest, windchill temperatures are reaching minus 60 degrees, the coldest ever recorded. In coming days, expected to get even colder. People can’t last outside even for minutes. What the hell is going on with Global Waming? Please come back fast, we need you! — Donald J. Trump (@realDonaldTrump) January 29, 2019

The Midwest right now is far, far colder than anything I experienced traveling near the North Pole.



That should scare the hell out of us, and be a reminder that climate change is not something that will happen "some day" - we're experiencing it EVERY day right now. — John Iadarola (@johniadarola) January 30, 2019

The backlash was instant, with Americans demanding how their President — who controversially pulled out of the Paris accord to reduce emissions in 2017 — could deny the widespread scientific consensus.

But experts explained that the chilly conditions were a result of the same problem, with the warming Arctic triggering changes in the jet stream and pushing polar air down to lower latitudes than usual, including the Midwest and Northeast of the US.

MAP REVEALS GLOBAL PROBLEM

Despite the cold in the US, global temperatures are still rising, and a map from the University of Maine Climate Change Institute shows the temperature were an average of 0.3C higher on on January 29 compared to the baseline.

Extreme weather events are becoming increasingly common, with research showing the frequency of winter polar-vortex events has increased over the past four decades.

The past four years have been the hottest on record, according to the World Meteorological Organisation, and ocean temperatures have broken records for several straight years.

Temperatures are rising fast twice as fast in the Arctic as the rest of the planet, which means there is less disparity in temperature between the North Pole and continents at lower latitudes.

That affects air pressure levels, which weakens the jet stream. This can disrupt the natural flow of the polar vortex, leading to the unusually cold weather at lower latitudes that we are now seeing in the US.

The US is looking to Australia to provide context for its big freeze, with the New York Times reporting on the extreme heat, bushfires, business closures and power shortages gripping the country. Australia’s drought “has gone on so long that a child in kindergarten will hardly have seen rain in her lifetime”, wrote the newspaper, noting that New Zealand had also broken heat records, despite typically being so temperate many people have neither heating nor air conditioning.

In the bitterly cold American Midwest, authorities have opened “warming centres” for homeless people, with buses driving the streets in the hope of preventing more deaths as the big freeze sets in. It comes just months after California was ravaged by its most destructive wildfires.

HOTTEST IN 80 YEARS

Extreme heat and drought is devastating the health and livelihoods of tens of millions of people worldwide, especially in South Asia, and destroying crops.

A PLOS Medicine study has predicted a fivefold rise in heat-related deaths for the US by 2080 and 12 times more in the Philippines.

In Australia, the Bureau of Meteorology reported that Adelaide’s West Terrace recorded its highest temperature in 80 years on January 25 at 3.36pm, breaking its 46.1C record by 0.5C and earning Adelaide the title of the hottest city on the planet.

The Adelaide Advertiser reported 28 suburbs and towns surpassed historic maximums, including Port Augusta, where the barometer reached a scorching 49.5C — the fourth-highest temperature recorded in South Australia — and Tarcoola, which broke its record for the second time in nine days, with 49.1C.

Weather watchers from the Higgins Storm Chasing group told their 780,000 Facebook followers that conditions were like a “blast furnace” and compared the heat to Black Saturday in 2009, when 173 people died in bushfires

SA Health chief medical officer Paddy Phillips said some parts of the state recorded four days above 40C in last week’s heatwave. “We saw 69 people present to hospitals across the state with heat-related conditions and 31 of those were admitted,” he said.

South Australia’s energy network was pushed to the brink and thousands of Victorians were left without power after the state’s third generator shut down, with Melbourne reaching a peak of 42C.

Residents in south and central parts of Tasmania were told to leave their homes, with temperatures in the high 30s and wind gusts of up to 90km/h fanning 50 fires burning across the state. At least 64,000 hectares of land has been burned.

“The best thing people can do in these conditions is leave early,” the Tasmania Fire Service warned. “A fire under the expected conditions can move very quickly with the potential for embers starting fires up to 20km ahead.

“Even those whose homes are well prepared to defend against fire will find their property is not defendable in these conditions.”

Authorities are fighting to keep pace with the extreme weather, with winds grounding waterbombing aircraft and ground crews forced to step in at some risk to their safety. Several fires have the potential to destroy communities, with properties lost and a fire southwest of Hobart burning since December 28.

The state fire service urged Tasmanians to use water sparingly and turn off taps and hoses if evacuating properties as the water mains could be under threat.

In Victoria, more than 2000 flying foxes were found dead with more of the creatures taken into care suffering heat stress. The Department of Environment, Land, Water and Planning confirmed on Tuesday that about 1400 of the native species were found dead near Bairnsdale on the state’s southeast coast, with another 900 dead at a Gippsland colony near Maffra.

In Northern Australia, the problem is torrential rain, with hundreds of millimetres expected on top of the hundreds already endured. A slow-moving monsoonal trough dumped more than 350mm of rain on the area around Proserpine, north of Mackay, in just 24 hours. It’s the same weather system that dropped almost 500mm on the Daintree River in 24 hours late last week.

A cool change over the past few days has brought brief relief for many Australians, but forecasters warned of “dangerous conditions” as bushfires are whipped up by blustery winds — and temperatures are set to soar once again into the weekend.

Temperatures may top 40C in NSW’s southern inland and by Sunday scorching temperatures will be returning in Melbourne, where it will be 38C.

Perth will see highs of 37C heading into a sunny weekend and Darwin will reach 31C with possible storms.

Cairns could see close to 500mm of rain over the coming week, with up to 150mm falling on Friday alone. The Bruce Highway remains cut in multiple places after torrential rain that caused the Daintree River’s record-breaking flood pushed south, dumping more heavy rain and stranding four campers.

The two women, aged 29 and 26, and two men, 31 and 28, became stranded while camping at Tabletop Station at Hervey Range. Rescue helicopters from Townsville were unable to reach the group because of the weather, with a mustering helicopter from Charters Towers called in to ferry the four to safety.

This January could be the warmest on record, and the record for the hottest Australian summer since records began could also be snatched.

“We’ve just come off the back of the hottest December on record. In this latest heat spell we had four days that were in the top 10 hottest Australian days on record and the hottest night on record,” said Sky News Weather channel meteorologist Rob Sharpe.

“We’ve had some serious heat and it has not really broken up. This next hot spell will take us through to the end of month so I wouldn’t be surprised if it was the hottest January ever. And if that happens it could be the hottest summer on record.”

However, the bubbling up of a monsoon could change things, particularly as January comes to a close. A tropical cyclone developing off the north coast is likely to bring rain into initially northern and central Western Australia. As this area is the engine of heat that often ends up in the southeast, it may bring down the highs.

“That could bring rain across a good proportion of the country and will break up that heat and bring a little bit of cooling,” Mr Sharpe said.