The Greek professor seeking answers in clouds

Copernicus Medal 2022 recipient Athanasios Nenes talks to Kathimerini about his work and climate change

The Greek professor seeking answers in clouds

Athanasios Nenes does not have his head in the clouds, but he does study them. He is attempting, together with his fellow scientists and research partners, to determine the complex process of cloud formation, the interactions between aerial particles, and their consequences on climate change. A pioneer among cloud “chasers,” of these “ghosts of weather and climate,” as he himself puts it, Nenes is the first Greek scientist to be awarded the Copernicus Medal in 2022. The award ceremony took placelast Thursday as a part of the European Geosciences Union (EGU) General Assembly in Vienna.

Nenes is a professor of atmospheric processes and head of the Laboratory of Atmospheric Processes and their Impacts (LAPI) at the Ecole Polytechnique Federale de Lausanne (EPFL). He collaborates with the Institute of Chemical Engineering Sciences at the Foundation for Research and Technology Hellas (FORTH) in Patra, where he is also the co-director of the Center for the Study of Air Quality and Climate Change.

The Copernicus Medal is a significant distinction in the geosciences and is awarded to scientists who are at the midpoint of their career. The criteria are significant scientific achievements and their wider impact on the scientific community. According to the official announcement, the 2022 award was bestowed upon Nenes for transformative contributions and fundamental advances at the interface of aerosol science with cloud formation, air quality, biogeochemical cycles and climate through a combination of theory, instrument development, measurements and modeling.

“We are trying to contribute to our understanding of the role of clouds in climate change. How they are shaped and how they impact it. We are helping to create reliable climate models for the future, that can be calculated relatively rapidly and can be useful in forming a political response to these changes,” Nenes tells Kathimerini. “It is clear that the planet is getting warmer. There is an ongoing process of climate change because of greenhouse gas emissions. The open question is whether it is a rapid change, like some models are showing, and which would be very negative, or if it is more controlled, which allows for some reaction time. The role played by clouds is very important, especially in climate change hotspots like the Arctic or the Mediterranean,” he adds.

‘Climate modeling shows that rainfall will become more extreme in western Greece and less so in the east, where there will now be increased instances of drought’

The interactions between clouds, particles and climate are very interesting. “In the 70s and 80s, when particle emissions were very high, there was a recorded reduction in the level of light that reached the ground, as clouds reflected part of it back. Even today we can see, as an example, that particle concentrations are linked to the displacement of monsoons in East Asia. They are very small changes, but they have been happening consistently for many years and have become systemic,” explains Nenes.

Why is the Mediterranean a climate hotspot? “Because it is warming up rapidly, at more than double the rate of oceans globally. In general, the impact on our region will be significant. Climate modeling shows that rainfall will become more extreme in western Greece and less so in the east, where there will now be increased instances of drought. This fuels the danger of more frequent wildfires. If we are not careful, this could even change the region’s flora, as frequent fires will result in a landscape with smaller plants, like those found in sub-Saharan Africa. Additionally, the smoke from those fires will be a serious issue, felt more widely than just the immediate areas. We must act and it requires a holistic intervention plan. We must not just pin it all on climate change and throw in the towel.”

We ask Nenes about the African dust that frequently blankets parts of Greece. “There are changes in the movement of aerial masses that lead to more frequent appearances of African dust. We should note however that, despite causing problems (particularly for respiratory systems), the dust is enriching our seas and land with nutrients and traces. We also observe that the presence of dust particles creates favorable conditions for storms, and snow in the winter months. There needs to be better monitoring of the phenomenon and timely warnings in case of extreme incidents.”

An observer of large-scale interactions, like that between the formation of clouds and their relation to climate, Nenes studies microscopic flying particles, moving between the very small to the very large and from old time-series databases to algorithmic models of the future.

Climate change is not the only thing that has been obscured by the thick fog of war, as the Covid-19 pandemic has also been forgotten after this “return to normality,” so what is the connection between Covid-19 and air pollution?

“It is now widely accepted that the primary means of transmission for Covid-19 is through air inhalation. This makes air quality, particularly indoors, critically important. My opinion is that we have to demand clean air in the same way we care about and demand clean water. We can use filters that remove viruses, other pathogens, pollution and dust. We need to care for our homes, but also add good ventilation systems with efficient filters in public buildings, workplaces, schools and universities, wherever there are many people. This is expensive but the benefits outweigh the cost,” he stresses.

“We must not reduce the level of humidity in indoor areas, because a dry respiratory system facilitates the activation of viruses in our body. An appropriate and healthy level for our homes ranges between 40% and 60% humidity,” he adds.

Ahead of receiving the Copernicus Medal, in a “celebration with friends,” Athanasios Nenes is thinking of his next projects and Greece. After all, the atmosphere is constantly shifting and changing.

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