As someone who has spent over a decade working on climate change, I’ve often felt like I have been waiting for the penny to drop: for society to recognise the catastrophe that we are heading towards. Would the brutal heat afflicting much of southern Europe finally be the moment when we would look up and realise things are going seriously wrong with the weather?
Extreme temperature alerts have been put in place across Spain, Italy, Cyprus and Greece as a dome of high pressure settled over the region. Surely now is the moment to put the spotlight on our continued burning of fossil fuels which risks plunging the climate deep into the danger zone?
Not so fast. The Telegraph this week offered advice on what to pack for a European holiday during a 45°C heatwave, while Good Morning Britain broadcast a surreal segment about whether the summer holiday period should be moved because getting heatstroke in a beachside resort isn’t most people’s idea of fun. Not even a mention of the impact flying to these destinations has on the climate.
The Italian Meteorological Society has named this latest heatwave “Cerberus”, probably in recognition of Dante’s 14th century classic Inferno in which the terrifying multiheaded creature Cerberus guarded the gates of hell.
There are two factors that turn hot weather into a lethal heatwave. The first is temperature. Thermometers in Sicily could exceed the all-time European record of 48.8°C next week.
The second factor is how long temperatures stay high. People can tolerate periods of very high temperatures if they are able to avoid heat stress during peak heat and can cool down overnight. Cerberus threatens to persist for up to two weeks, during which there will be very hot days and nights.
Recent research published in Nature Journal on the impacts of heatwaves in Europe last year concluded that over 61,000 people died from heat-related illness. To thousands of people, Cerberus will not just be uncomfortable or an inconvenience, it could be deadly.
Cerberus is just one of multiple recent heatwaves across the world. We are also witnessing record breaking ice loss in Antarctica. This year is firmly on course to be the warmest year in the instrumental record, probably the hottest year for many thousands of years. Has the climate tipped into a new hotter state?
There are some reasons to think that 2023 may prove to be an exceptional year. The first is the Tonga volcanic eruption in January 2022. Volcanoes often have an overall cooling effect on the climate because they emit so much dust and gas into the atmosphere. This reflects away some of the energy from the sun.
Tonga was different in that it produced less dust but much more water vapour. Tonga is an undersea volcano in the south-west Pacific. When it erupted it vaporised a vast amount of water and hurled it up into the stratosphere. It was soon suspected that this could have a global warming impact as water vapour is an important greenhouse gas and can persist for a couple of years when it gets so high up into the atmosphere.
The other factor in play is the El Niño that is emerging. El Niño is cyclical climate phenomena that produces a band of warm ocean water in the central and east-central equatorial Pacific. One way to understand El Niño is that it is a process that draws up some of the vast amount of heat in the oceans and moves it into the atmosphere. This is a natural process with a global warming effect that lasts around four years.
Conditions can then switch to a period of cooler conditions termed La Niña. Until that happens, expect more temperature records to be broken, along with more drought in some areas, floods in others. Volcanoes, El Niño, and changes in the brightness of the sun are all sources of natural variability. But they cannot explain the record-breaking weather we are witnessing.
Imagine lying in a bath full of water. If you keep the tap open and allow water to continue to drip into the bath then the total amount of water will go up. The rate at which that goes up may be impossible to see – like trying to watch a clock’s hour hand move.
It will be much easier to see the water level change as you move and slosh the water around. If you keep the tap open then eventually there comes a point when another shift of your body means the water spills over the side of the bath. It’s been the steady flow of carbon dioxide gas into the atmosphere over the past couple of centuries that has raised levels of this greenhouse gas in the atmosphere.
While we’ve been able to monitor directly the increase in atmospheric carbon dioxide since the 1950s, wider society only really notices the impacts its having when the weather starts to “slosh” about. The sloshing may be natural, but it’s the overall level that has increased, and so turned what would have been a period of hot weather into a lethal Cerberus.
Dante’s use of Cerberus was inspired by Greek mythology in which the mythical beast guarded the gates of hell. Not from those unwary or unwise enough to try to enter, but to stop the undead from leaving. We still have time to avoid the jaws of irreversible and potentially catastrophic climate change snapping shut. Our route to safety is stopping burning coal, oil, and gas. Until that happens, we will continue our descent into the inferno.
James Dyke is an associate professor in earth system science at Exeter University
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