Southern summer | The Southern Hemisphere is suffocating

As a cold snap sweeps across central and eastern North America, heat records are piling up in the Southern Hemisphere, from Australia to Argentina, Uruguay and Paraguay. The climate crisis is no stranger to this.

Jean-Thomas Léveillé
The Press

The mercury refuses to drop in Perth, Australia, where the temperature exceeded 40°C for the sixth day in a row on Sunday.

The austral summer is particularly hot this year, throughout the west of the country-continent, where records are falling one after the other.

The number of days when the temperature exceeded 40 ° C was already eleven, Sunday, unheard of in a year, while the month which is usually the hottest in the summer, February, is not not started yet.

In Onslow, just over 1000 km to the north, the temperature soared to 50.7°C on January 13, breaking a temperature record for the state of Western Australia and equaling the absolute record for the Whole Australia, recorded in 1960 in Oodnadatta, South Australia.

This record is all the more astonishing since Onslow is a coastal town, tempered by the ocean breeze, unlike Oodnadatta, located in the arid heart of the country, underlined in an interview with The Press Omar Baddour, head of the climate monitoring and policy section at the World Meteorological Organization (WMO).

South America

Extreme heat has also hit various South American countries since the beginning of the austral summer.

Temperatures approached their historic maximums on Thursday in several places in Brazil and Argentina, where heat waves have persisted, in some cases for more than two weeks.

“That’s quite exceptional, the duration of this heat wave, especially in the northern part of Argentina”, declared to The Press Alejandro Di Luca, professor in the Department of Earth and Atmospheric Sciences at the University of Quebec in Montreal (UQAM), specialist in climate extremes.

Earlier this month, Uruguay equaled a 70-year-old record on January 14 when the temperature soared to 44°C in Florida, a city about 100 kilometers north of the capital, Montevideo.

Paraguay, for its part, set a new heat record on 1^er January, or 45.6 ° C, recorded in Sombrero Hovy, in the north of the country.

These extreme temperatures are caused by heat domes, like the one responsible for the Canadian record of 49.6 ° C, last summer, in Lytton, British Columbia, explains Alejandro Di Luca.

Normal heat, abnormal frequency

The extreme heat recorded in the southern hemisphere has nothing “supernatural”, observes Omar Baddour, of the OMM. It is their multiplication and their intensity that are out of the ordinary.

“We are starting to record records not in one place, but practically on all continents, where we have values ​​of almost 50°C, he says. It’s not quite natural. »

Heat waves now occur in a warmer context, due to global warming, adds Alejandro Di Luca.

“These heat waves, which would have occurred anyway, are superimposed on a general warming, he explains. Add 1 or 2°C, and they become record-breaking heat waves. »

The austral summer could well continue as it began, maintains Alejandro Di Luca: “We are still only in the middle of summer. Chances are there will be more heat waves. »

Above all, this extraordinary summer risks repeating itself, warns the professor.

“Climate change will continue until we achieve global carbon neutrality, which is not for tomorrow,” he said. These trends will continue and are likely to exacerbate. »

More extreme heat in the Northern Hemisphere

The heat records recorded by the Southern Hemisphere still pale in comparison to those of the Northern Hemisphere. The world record for heat on Earth was recorded on July 10, 1913 at Furnace Creek, in Death Valley, California; the mercury had risen to 56.7°C. The southern hemisphere is more temperate because it’s dominated by oceans, unlike the northern hemisphere, says WMO’s Omar Baddour. There is also no correlation between the cold that is currently raging in the North and the heat that afflicts the South, explains the scientist. “There is no penetration of weather systems between north and south,” unlike the “east-west ripple phenomenon” that is sometimes observed.