In late June and early July, a heatwave swept through Europe bringing with it  temperatures of over 40 degrees Celsius (104 degrees Fahrenheit) in many countries.  

The sweltering heat forced schools to close, prompted bans on outdoor work across most of Italy, and created hot, dry conditions that fueled wildfires in several countries. Copernicus, the EU’s Earth observation service, said June was the hottest on record for western Europe. 

Meanwhile, on the other side of the world, Argentina, Chile and Uruguay were grappling with a rare polar cold wave.  

Cooler conditions are not unusual in the southern hemisphecre winter which runs from June to September. But on the last day of June, both Chile and Argentina ranked as the coldest places on earth outside the polar regions.  Southern and central Argentina had temperatures between 10-15 degrees Celcius (50-59 degrees Fahrenheit) below the seasonal average.  

Buenos Aires recorded the lowest temperatures since 1991 and snow blanketed unusual locations including the Atacama Desert, known as the driest place on earth outside of the poles, for the first time in a decade. 

According to meteorological services in the region, many weather stations set new records with some falling below –15 degrees Celcius. Governments were forced to restrict gas supplies after electricity demand caused cuts and move homeless people to emergency shelters.  

What’s behind the extremes?  

The cold snap in southern South America was due to what is known as a powerful polar-origin anticyclone.  

"What happened this week in Chile and the Southern Cone in general is a cold wave caused by an escape of a polar air mass from Antarctica," climatologist Raul Cordero from the University of Santiago told the AFP. 

Another meteorologist told the news agency that the rarity of the event in this region made it hard to rule out the possibility of the cold snap being related to climate change.  

Some researchers have proposed that Arctic warming could disrupt patterns of atmospheric circulation, leading to cold polar air flooding out of the regions. However, many climate scientists argue that extreme cold spells in temperate regions are decreasing in a warming world, and have dropped in intensity and frequency in recent decades.  

The blistering temperatures in Europe, however, were fueled by the emergence of a “heat dome", a meteorological phenomenon where high-pressure keeps dry, hot air over one region for a long period of time. 

John Marsham, Joint-Chair of the Met Office, the UK’s meteorological service, at the University of Leeds, UK said the role of climate change in the recent high temperatures in Europe is absolutely certain. 

“One of the strongest fingerprints of climate change is the increase in extremes and that's particularly true for heat waves and high temperature extremes," said Marsham.  

Climate change is believed to have tripled the number of heat-related deaths in the recent European heatwave, according to a rapid study led by scientists at Imperial College London and the London School of Tropical Medicine.  

The study estimates the burning of fossil fuels increased the temperatures in the heatwave by up to 4C across 12 European cities, increasing the number of expected heat-deaths by 1,500.  

"Heatwaves don’t leave a trail of destruction like wildfires or storms," said Ben Clarke, research at the Centre for Environmental Policy at Imperial College London. "Their impacts are mostly invisible but quietly devastating — a change of just 2 or 3°C can mean the difference between life and death for thousands of people."  

The EU’s Copernicus stated that during the heatwave, large parts of southern Europe experienced an unusually high number of "tropical nights"  — where temperatures remain above 20° C (68 degrees Fahrenheit). This can pose a health risk by preventing the body recovering from daytime heat. 

In the future Europe will for sure experience more heatwaves and more intense heatwaves, said Lara Wallberg, climate scientist at the Max Planck Institute for Meteorology in Hamburg, Germany. "Heat extremes that are now rare events might be very, very common at the end of the century. So I guess our impression of what an extreme is might also shift."  

What about other types of extreme weather?  

And it is not just heatwaves, climate change is super charging extreme weather events such as floods, drought and storms making them more frequent and intense.  

Just a small change in global mean temperatures can lead to a big increase in extremes, said Marsham, adding he expects climate change to have played a role in the severe Texas flooding last weekend, which has claimed over 100 lives with many more still missing.  

A 2024 study saidthe intensity of extreme precipitation is expected to increase 10% by 2036 in Texas. While modeling precipitation patterns is a complex process, it has one clear underlying physics principle: hot air holds more moisture.   

According to the IPCC, at 2 degrees Celsius (3.6 degrees Fahrenheit) of warming above pre-industrial levels, what would have been a once-every-10-year rainfall event will occur 1.7 times per decade and be 14% wetter. 

"I think it's really important that people understand that this is not the new normal. It's going to carry on getting worse until we phase out fossil fuels and reach net zero," said Marsham. "We have to prepare for unprecedented events." 

Despite the rising threat of extreme weather, society is not acting with enough alarm, Michael Oppenheimer, climate scientist at Princeton University, told The Associated Press. "There's plenty of evidence that we sit there and do absolutely nothing while these risks are coming right at us like a moving railroad train and we're standing in the tracks. And then all of a sudden, bam." 

Edited by: Tamsin Walker