Is climate change the cause of the heat wave? Here’s the simple science behind Europe’s scorching weather


For hundreds of millions of people in Europe, the unbearably hot weather this week is the cause of climate change.

Temperatures in the UK are set to hit 40C for the first time in recorded history, while France, PortugalSpain, Greece and Croatia have been battling wildfires for days, if not weeks.

We know that global warming is the cause, and it’s a simple link to make during a heat wave. (Although dangerous climate skeptics are still published in national newspapers, bending over backwards to claim that it is because the Earth is getting closer to the sun).

But if you’re feeling a little fuzzy about the science, or need a few points to persuade the inactive climate in your life, we’ve got you covered.

How are climate change and heat waves related, exactly?

The planet’s average temperature has risen 1.1°C since pre-industrial levels, largely due to the huge increase in greenhouse gases that human activity has unleashed. Carbon dioxide (CO2) is the biggest contributor to global warming; its concentration in the atmosphere has increased by 48 percent between 1750 and 2020.

Like glass in a greenhouse, CO2, methane, nitrous oxide and other gases trap heat from the sun, causing less heat to return to space.

As average temperatures rise – closer and closer to the 1.5C mark which will be disastrous for many countries – the amount of weather at the “extremely hot” end of the spectrum is increasing, making episodes of extreme heat more frequent, longer and more intense.

According to a recent expert studya heat wave that would have had a 1 in 10 chance of occurring in any given year in the pre-industrial climate will now occur almost three times more frequently on average and be 1.2°C warmer. heat that would have struck once in 50 will strike five times as often.

What can scientists tell us about the cause of heat waves?

“I think we can confidently say that every heat wave that occurs today has been made more intense and more likely due to climate change,” said co-author Dr. Friederike Otto, master of climate science lectures at the UK’s Grantham Institute for Climate Change. the environment.

In other words, we no longer have to wait for “attribution studies” to prove that climate change is making heat episodes worse. However, such research is still very valuable.

A study by World Weather Attribution (WWA) has revealed that the heatwave that destroyed a Canadian village last summer – after a record 49.6C was followed by a wildfire – has been rendered 150 times more likely by climate change. It would have been “virtually impossible” without it, the climatologists concluded. Those who returned to rebuild Lytton were again evacuated last week.

Dr Mariam Zachariah, who also works at the Grantham Institute and the WWA, said “there have been so many extreme events this year, it has become difficult to watch them all”.

Focus on the events that had the most impact on people and agriculture is, however, a key element of climate communication. Despite the alarming data sets she manages, Dr Zachariah tells Euronews Green: “The message is that we have to start taking action, and I have a lot of hope for us; if we act in time, we can do enough to adapt and mitigate climate change in the future.

What causes the heat wave in Europe – and how hot will it be?

Severe weather conditions are, of course, relative to “normal” conditions. In the UK, meteorologists define a heat wave as a period of at least three consecutive days when daily maximum temperatures reach the temperature threshold – which varies by county. In London, for example, it is 28C.

In response to a fake forecast image shared online – suggesting the Met Office is only making regular summer temperatures more extreme – Met Office meteorologist Aidan McGivern has shared some insight into the visuals from the National Weather Service.

After redesigning the new temperature color scale last year to make it accessible to color blind people, he revealed he ‘never expected’ dark red to be used on maps of the UK.

“We were hoping we wouldn’t get to this, but for the first time we are predicting over 40C in the UK,” Met Office climate attribution scientist Dr Nikos Christidis said, announcing the whole thing. UK’s first red warning for exceptional heat. .

“The chances of seeing 40C days in the UK could be up to ten times more likely in the current climate than in a natural climate unaffected by human influence.”

Heat waves are usually caused by high pressure systems. In this case, it was the ‘Azores High’ – an anticyclonic system usually found off Spain in the North Atlantic – that spread northward and created the conditions we feel today. today. This atmospheric region is also expanding due to climate change, a recent study shows.

Added to this are hot, dry winds blowing in from North Africa and the Sahara, Annie Shuttleworth of the Met Office warned last week. Wales and Ireland have already recorded their hottest temperatures on record so far.


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