“Climate change is about watching a series of videos of climate disasters recorded on cell phones, closer and closer to home, until one day you are the one recording.” This meme which has been circulating on the Internet for a long time has found new life after the DANA which left dozens of dead on the Spanish Mediterranean coast.
Although it will take attribution studies to establish the degree of direct relationship between climate change and this episode, what we already know is that record ocean temperatures and increased moisture retention in the atmosphere are the perfect ingredients for this to happen. increase in frequency and intensity. And that the alteration of atmospheric flows produced by global warming has a determining role.
The recent torrential rains in the Sahara Desert or the unprecedented speed with which Hurricane Milton reached Category 5 before hitting Florida are just two recent examples of extreme climate anomalies produced by this atmospheric situation. In the case of DANA which struck the Spanish Mediterranean, the elements involved are similar.
“There is more humidity in the atmosphere because the Mediterranean is warmer than normal,” explains Francisco J. Tapiador, professor of Earth physics at the University of Castilla-La Mancha (UCLM). “This produces ‘strange’ circulation patterns, given that the Mediterranean climate is inherently variable.”
We are seeing very strange and very twisted wave patterns. Sometimes they are strangled and generate this type of depression at high levels like DANA.
Francisco J. Tapiador
— Professor of Earth Physics at the University of Castile-La Mancha (UCLM).
If we open the frame, we see that the so-called jet streams are destabilized and lead to more episodes of extreme heat and cold, and that phenomena such as the intertropical convergence zone are moving much further north than usual, which explains why the Sahara has recently been filled with small lagoons.
“We’re seeing very strange, very twisted wave patterns,” says Tapiador. “Sometimes they strangle themselves and generate this type of depression at high levels like DANA.” And part of these effects are a consequence of the melting of the polar cap and record temperatures at the poles. “What happens in the Arctic affects us because it changes the trajectory of the jet stream, and it affects the DANAS,” explains the expert.
She’s not “crazy”, but she is “twisted”
“It’s not so much that the atmosphere is mad“says the seasoned meteorologist Angel Riveraexpert in atmospheric dynamics. “What’s happening to the atmosphere is that it has a more undulating circulation than it did a few years ago and that’s probably related to the problem of more warming of the tropical atmosphere.” These deeper, sharper ripples cause warm tropical-subtropical air to rise toward higher latitudes through large ridges, which generate these huge heat waves we’ve been seeing lately, Rivera says.
On the other hand, when there are oscillations of cold air towards the south, the contrast between this cold mass and the warm mass becomes much narrower and this makes the winds which circulate around this disturbance that is the DANA more intense. . “It gives its front area a lot more intensity, a lot more lifting power and causes stronger storms,” he says.
The circulation of high levels and the supply of heat and humidity from lower layers are the perfect cocktail to cause this type of situation.
Angel Rivera
— Meteorologist expert in atmospheric dynamics
In other words, it is atmospheric warming – produced by human activity – which gives rise to more undulating circulations, with much more pronounced troughs and crests, so that these disrupted “rivers” in the sky leave more cold and heat waves and more extreme phenomena. . “If we add to this the fact that in the lower layers the air is quite warm and humid,” explains Rivera, “this means that the engine, which is the circulation of high winds at altitude, and the supply of fuel coming from the gasoline of the lower layers, are the perfect cocktail to cause this type of situation.
A long way to go
“The jet stream or jet stream, Due to the changes we are observing due to climate change, the ripples are more pronounced,” recognizes María José Sanz, director of the Basque Center for Research on Climate Change (BC3), in statements to the SMC. DANAS are areas of low pressure that are isolated from that jet stream, remember, and added to that are atmospheric rivers, certain currents in the atmosphere that carry water vapor.
The tragic consequences of this event demonstrate that we have a long way to go to prepare for these types of events, and worse, in the future.
Liz Stephens
— Professor at the University of Reading.
“In general, several decades passed between events of this type, now we can see that they occur more frequently and that their destructive capacity is greater,” assures Ernesto Rodríguez Camino, senior meteorologist of the state, in declarations to the SMC. “Climatologists have been warning for years that climate change will lead to more rainfall,” concludes Liz Stephens, professor at the University of Reading. “And the tragic consequences of this event demonstrate that we have a long way to go to prepare for these types of events, and worse, in the future. »
Finally, linking this meteorological event to climate change is not crazy, knowing that other previous attribution studies have shown a direct relationship between global warming and episodes such as the “derecho”, which caused a dozen deaths in southern and central Europe in 2017. August 2022 or the increase in giant and potentially fatal hailstorms.
For Juan Jesus González Alemánlead author of this work and expert in atmospheric dynamics at AEMET, extreme events like those he documented are those that climatologists warned us would occur if we continued gas emissions and the increase of the temperature. We will have to wait for the evidence of this new catastrophe, but for now the predictions are coming true point by point.
