How climate change is making extreme weather a regular occurrence
In France, a particularly intense heatwave is set to start on July 11, lasting over a week with temperatures of more than 38°C in a large portion of the country. The exceptionally warm weather will also hit the Iberian peninsula, with temperatures over 40°C in Spain and Portugal, and the UK. This comes after France, Portugal and Spain experienced heatwaves in June, and Spain recorded the hottest May weather since the beginning of the century.
Firefighters in France have already raised concerns over the increased possibility of wildfires due to dry, hot weather.
At the end of June, Japan too was hit by an unprecedented heatwave. The mercury rose to 35°C for consecutive days in the capital, Tokyo, and up to 40°C in Isesaki in the centre of the country. Such consistently high temperatures broke records for the time of year, and were swiftly followed by torrential rains across the Japanese archipelago.
Across the Pacific Ocean, the western states of the US have been hit by significant droughts that are becoming an annual event. This year, however, experts are concerned that reservoir levels will fall so low that the Hoover Dam will no longer be able to produce electricity for hundreds of thousands of American homes.
As a result of the heatwave, part of the glacier detached itself and fell, killing 11 people. The following day, a pine forest south of Rome was the starting point for a forest fire.
'Interconnected phenomena' intensified by climate change
These extreme weather events happing at almost the same time in multiple locations around the world are “absolutely not a coincidence", says Pascal Yiou, climatologist and researcher at French research centre le Laboratoire des sciences du climat et de l'environnement. “These meteorological phenomena are interconnected. A cyclone or a heatwave in the US has repercussions on the whole planet contributing to monsoons in India, for example.”
While it is not unusual for such events to occur in tandem, there is still the question of why they are occurring with such intensity. Yiou says global warming is to blame. “It is disrupting the whole dynamic of the atmosphere,” he says. “Rising temperatures at the poles disturb wind energy and, therefore, the alternation in cyclones and anticyclones.”
Global warming creates, for example, favourable conditions for conflicts of air masses between the ground and high altitudes. These conflicts can cause phenomena such as “cold drops” when a bubble of cold air collides with warmer temperatures close to the ground causing heavy rain and storms. The opposite, when a bubble of warm air collides with cool air at ground level, can cause heatwaves.
Then there is a domino effect. One heatwave can intensify a drought or cause forest fires. Heavy downpours can kick start floods or landslides.
Climatologists such as Yiou say this vicious cycle is cause for alarm. Climate experts from the UN announced a “code red for humanity” in a 2021 report that said that heatwaves, floods and other extreme weather events would increase in an “unprecedented” way, in terms of frequency, scale, areas impacted and periods of the year when they may occur.