"We correct the ozone hole, but we have not yet resolved climate change"

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In the cafeteria of a well-known hotel in Valencia, an affable man who could go unnoticed by any street in our country, has a quiet conversation about issues of great importance. No one would say that, 25 years ago, he saved humanity from an unprecedented disaster .

"At the beginning many scientists believed that the ozone hole was a natural thing," he says simply. "But it was very clear that it was the industrial compounds, which we had predicted, that were causing it." Thus, with few words, it resolves the resolution of one of the most serious problems that life on our planet has faced. "Fortunately, it could be resolved," he says and smiles.

He is Mario Molina Pasquél y Henríquez (Mexico City, 1943), chemical engineer and Nobel Prize for this discipline in 1995, shared with Paul Crutzen and Sherwood Rowland , for his contribution to determine the origin of the ozone hole. For this reason, the Valencians have signed him as a jury to highlight the work of the researchers of our country in the prestigious King Jaime I Awards, in a tribunal made up of 19 nobles.

Now, the world is facing a more complex global problem and its serious consequences: climate change and the increasing extinctions of the biosphere. To find the key to these questions, we will need your help or the help of scientists who, like him, drive the advancement of knowledge.

We are surprised now with a work on the effects of contamination in the womb. Not even the fetus escapes the stale air we breathe? The important and surprising thing is that the contaminating particles penetrate the reproductive system of mammals. There is an impact that can be measured even at the level of the fetuses, during their development, which is no longer normal. And this is what is surprising, how delicate that process is. It is an indication that there is vulnerability, that particles have impacts at many stages of life. The most worrisome occur in children's lung development, measured with epidemiological studies. With the fetuses it is done experimenting and we have seen that they have very clear impacts on the fetuses of the rats. You cannot do experiments with human fetuses. This is a serious problem in cities. We have tried to understand at a very fundamental level the chemistry of the atmosphere and how these particles are produced. Emissions are concentrated in urban centers. We already have enough information to try to reduce the amount of these particles in polluted cities. Half are emitted directly, for example by cars, especially diesel engines. And the other half is formed in the atmosphere by chemical reactions. The problem is in the city, where the activity of society has increased the number of particles in the atmosphere. They do not last long, because rain, in general, can clean them. But in a city like Mexico City, where I live, during the summer, it rains, there is not much pollution. But when it doesn't rain, they can increase the levels of these particles. How does it affect us? Small particles do not seep through the nose like large ones. The dust does not reach the lungs, but the smallest produce a whole series of impacts. They reach the pulmonary alveoli and enter the circulatory system. That is why it is important for society to try to reduce emissions, either from particles or from particle precursors. This is the most serious problem of contamination. His work, along with that of Paul Crutzen and Sherwood Rowland, was key to ending CFC gas emissions into the atmosphere. You held the human species responsible for the ozone hole. We discovered that these industrial compounds were eventually causing the hole in the ozone layer over Antarctica. It is very spectacular because normally there is a lot of ozone and in a matter of one or two weeks, in the spring, when the sunlight begins to arrive, more than 95% of the ozone that protects from ultraviolet radiation disappeared. Hence the importance. At the beginning many scientists believed that the ozone hole was a natural thing, which could not be caused by human activities. But it was very clear that it was the industrial compounds, which we had predicted, that were causing it. Has the ozone layer problem been resolved? Fortunately, it could be solved with the Montreal protocol. The entire planet agreed not to produce these compounds. But since they last a long time, what we see this century is the result of what was issued last century. Since the 80s, little by little, ozone has been reinforced very clearly. It has not fully recovered, because some of these industrial compounds last more than a century until they decompose, but it is already being resolved. Now the focus is on climate change. Will we be able to solve this other global problem in the same way? Before we talked about air pollution in cities. But outside of cities we have global problems caused by changes in the chemical composition of the atmosphere of the entire planet. They are no longer just cities, but everything. And there we have basically two important problems: the problem of the ozone layer (which is what I worked with) and climate change, which we have not solved and is very serious. Now we know that global problems can be solved. But climate change is much more difficult, because it is connected to the use of fossil fuels. This is a very important part of the economic growth of all developing or developed countries. How can it be addressed? Fortunately, pollution and climate change are connected. The clearest connection we see in China. There the cities have grown a lot and there is a lot of local air pollution, especially by small particles. This was caused, in large part, by the use of coal to produce electricity. Coal also produces carbon dioxide, the most notable greenhouse gas and the most important cause of climate change. China has stopped growing so quickly. He no longer builds a coal plant a week, as it was happening until relatively recently. Thus they have improved air quality in Beijing and in Shanghai. The problem of air quality and climate change attacked him simultaneously. If they had not had this problem in air quality, who knows if China had taken these measures. What do you think of the great extinctions of species that occur throughout the planet? Is this the new ozone hole of our day? It is another global problem that is combined with that of climate change. Global problems are clearly caused by the activity of society, because it does not matter where emissions occur as they damage the entire atmosphere. That of extinctions is a biological problem that is local, but it is happening in so many parts of the planet that it is a serious problem. When the climate changes, the ecology changes and that is one of the main causes of the disappearance of species. In part, also because of the cultivation, which makes many forests disappear. Climate change is changing ecology in many places. We correct the hole in the ozone layer but we have not yet resolved climate change. This is what we have now to work hard.

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