Scientists’ modelling is proving correct as high pressure sends mercury soaring, writes Caroline O’Doherty
To escape the heatwave in Portugal, residents and visitors had few options, and one involved scaling the peak of the Portuguese equivalent of Carrauntoohil.
The Foia mountain is, at 900 metres, just a little below Ireland’s highest peak. It is also one of only three areas in Portugal that avoided temperatures of more than 30C in recent days.
The other two were high, exposed peninsulas on the west and southwest coast.
Every other district in the country hit 30C or higher. In fact, 88pc of districts hit 35C or above, 40pc reached 40C and 15pc hit 42C or higher.
In one district, it climbed to 44.6C.
Little wonder the country declared an eight-day state of alert even if staying alert in those unrelenting temperatures – rarely dipping below 20C at night – is a challenge in itself.
Neighbouring Spain is having similar issues, with 44-47C forecast in places over the coming days.
France and Italy are also sweltering and the story changes little the further into central Europe you go.
Wildfires, water shortages, heat exhaustion and malfunctioning utilities are making handling the heatwave all the harder.
Air quality has also taken a dive. Copernicus, the EU’s atmospheric monitoring service, shows surface ozone concentrations above safe levels in many areas.
Forget the protective layer in the atmosphere that shields us from the sun, surface ozone is different, creating a dirty smog of exhaust fumes and other pollutants that hang in the air at perfect height to inhale.
But you do not even have to go as far as those holiday hotspots to experience extreme temperatures.
Across the water, the UK Met Office has issued a “danger-to-life” warning to run until next Tuesday in England and Wales.
“Population-wide adverse health effects are likely to be experienced, not limited to those most vulnerable to extreme heat, leading to potential serious illness or danger to life,” it said.
Next Monday, temperatures in London could climb to 40C, which would knock the all-time UK record of 38.7C off a perch it claimed as recently as 2019.
Ireland too is set for warmer-than-average weather with temperatures expected to be in the mid to high-20s over Sunday and Monday, “possibly surpassing 30C locally on Sunday”.
Compared to much of the rest of Europe, that is benign, but in a country that melts at anything over 20C, it will bring its own challenges.
What is happening across Europe, and why Ireland is escaping the worst of it, is explained by Met Éireann meteorologist Paul Downes.
The main issue is the behaviour of the “Azores High”, a large area of high pressure that sits out in the Atlantic Ocean all-year round, closer to Europe than the US.
In winter, it can block the rain that normally comes with the jet stream coming from the west and leave mainland Europe drier while pushing those rains upward, towards us.
In summer it can have a similar blocking effect, particularly if it behaves unusually, which is the case at the moment.
Scientists from the Potsdam Institute for Climate Impact Research published a study a few weeks ago that show it has become more changeable in recent decades.
Currently it has extended and shifted north, interrupting the jet stream and slowing everything down.
“High pressure is still building over Europe,” Mr Downes said.
“It’s added to by the fact that it’s heating up land which is dried-up land at this point so it heats up very quickly.
“The fact that the continent is such a large land mass will help to generate that high pressure as well.”
When the land heats up and that heat gets trapped in a stationary weather system, the temperatures intensify and create a heat plume which makes conditions all the more brutal.
To complicate matters more, the Azores High is expected to move back toward mainland Europe in the coming days, interact with a low-pressure system that is pushing off Portugal and drive that very warm air up over Ireland.
“The jet stream generally has a flow going west to east. That’s why we’re more influenced by the Atlantic conditions and have generally more of a mild maritime climate,” Mr Downes said.
“But when it does flip around and we get air flowing from the south east and east, we generally get these sort of situations with extreme temperatures, be it warm in summer or cold in winter.”
By extreme, he means extreme Irish-style, so it is unlikely temperatures will stray far into the 30s, but this weekend will bring warmer weather than we are generally comfortable with.
“We all like the heat but when you start to get into the upper 20s and low 30s with no air conditioning, it’s not the easiest to cope with.”
The forecast for Tuesday/Wednesday onwards is for thundery showers and a return to more normal summer temperatures.
But for a broader understanding of what is happening, look-backs rather than forecasts are the most revealing.
Scientists have been warning for years that climate change would bring higher and more persistently high temperatures and their modelling is proving correct.
While Spain and Portugal have often had intensely warm periods, parts of Spain had temperatures in the 40s in May this year – much sooner than usual and far too early for comfort.
The wider heatwave began in June and there has been little relief since.
According to Met Éireann: “While extremely hot weather does occur within natural climate variability, the kinds of temperature extremes we are seeing in Europe are directly influenced by climate change.
“June 2022 was Europe’s second warmest on record and the US’s warmest. The eight hottest Junes on record globally all occurred in the last eight years.”
Keith Lambkin, Met Éireann climatologist, said: “Due to climate change, we are expecting to see heatwaves become longer, more frequent and intense than in the past. This increase in heat increases the odds of temperature records being broken.”