The rains in Madrid they sowed chaos in the city during the afternoon of yesterday, May 29, 2023. In just half an hour they were counted 30 liters of water per square meter, which meant the cutting of metro lines, kilometer delays on roads and flooding in many parts of Madrid, including some hospitals. All this occurs after an abnormally hot and dry start to spring, so there is no doubt that it is one of the effects of the climate change. And this is only the beginning.
There are many places in the world that are seeing other climatic phenomena as extreme as the Madrid rains. For this reason, a team of Japanese scientists got down to work to develop a future flood map.
Thus, it will be possible to know which will be the places most affected by this drastic consequence of rainfall and take action in advance. The map is not finished yet, but scientists have already given some data on what the situation will be in just 100 years. And, indeed, the rains in Madrid are only an appetizer of what seems to be to come.
Consequences of the rains in Madrid
The DANA which has been installed on the Iberian Peninsula for more than a week has now been primed with the Spanish capital.
Hail and rain in Madrid they left countless incidents yesterdayalthough, luckily, no victims.
Even so, planes bound for the Barajas airport could be seen diverted, flooded hospitals, cut metro lines, delays of up to 29 kilometers on some roads and even firefighters swimming across streets.
Despite what Filomena supposed, this city is not used to suffering this type of catastrophe. And it is that the rains in Madrid are one more example of what is to come. extreme events such as drought and floods they will become more and more habitual; for which, at least, we must be prepared.
A flood map of the whole world
The objective of these Japanese scientists is to develop a map of the whole world in which the hot spots in which floods will become very common.
To do this, they used the macroscale floodplain model, based on the channeling zone (CaMa-Flood). It is a model that represents the flow of channels and the flooding of the plains. He explained it last month in a statement the lead author of the research, Yuki Kimura: “We used runoff data to generate flood risk maps, lowering simulated river water levels to 100m resolution elevation maps.”
Subsequently, three flood risk maps. The first was based on Historical facts about extreme precipitation and flooding in each part of the world. In contrast, the other two focused on the opposite: the future predictions. These were obtained in two ways: by the runoff correction method and the search method. Both differ in the handling that is made of the data, so that different estimates are made. Once they were obtained, they were compared with the historical data, in search of a pattern of advance of the floods.
The truth test
To find out if the two predictions work, they took two real examples of floods. those of the Chi-Mun river basina Chinese river tributary of the Mekong, and those of the Amazon.
Once they compared the two predictive methods with actual historical data, they saw that both predictions, when extrapolated to what had already happened, worked for the Chi-Mun. However, the runoff correction method seemed to have some inconsistencies for the case of the Amazon.
Thus, they decided to base themselves on the search method for the elaboration of their flood map. This allowed them to establish that there are currently 1.860 million people living in areas where the magnitude of flooding will exceed a historical return period of 100 years. The return period is the average number of years with which a catastrophic event will be exceeded. That is, if it is 100 years, that will be the time it will take on average for there to be a worse flood than the previous one. They may seem like many, but it is what is considered an average or occasional probability. It is not high, but it is not an exception either.
And, for the moment, it is underestimated. In fact, according to the authors of this study, if only historical data is taken into account, it is estimated that there are 200 million people less at risk from this type of flooding.
At the moment they have only established how to make the models. But, given their success, we could soon have the final map. A map to know if the floods caused by the Madrid rains they have only been the starting signal for something much worse. The good part is that, if we fight climate change, we have time to slow down the advance of these data. We already know what we have to do, it’s time to start.