More fertile cities for the climate

Make 100 cities climate-neutral by 2030: This is one of the five major missions that Europe has set itself as part of the Horizon Europe research program. Christoph Menezo, a specialist in photovoltaic solar energy, explains how research solves this problem.

Although they make up only 4% of the total area of ​​the European Union, agglomerations account for 75% of its population and 70% of carbon dioxide (CO) emissions.2). Horizon Europe relies in particular on smart cities to lower this last figure. But what is it?
Christoph Menezo. I am well aware of this issue because I am responsible for one of the areas of Synergie, an international Franco-Singapore renewable energy research network that is interested in smart cities. These “smart” cities, one of the best examples of which is Singapore, benefit from many technological innovations in construction, mobility, resource management and recycling. But such a complex system must have data for analysis obtained through a network of sensors that continuously measure various industrial, energy, environmental or social parameters. Their operation applies to such disciplines as materials science and carbon-free energy, economics, law, psychology, philosophy, history, geography and more.

In Tianjin, a Sino-Singaporean green city that opened in 2008, energy-saving LED street lights are powered by wind and solar energy.

Because if we have ambitious goals, such as the goals of Horizon Europe, we must be able to follow the trajectories that we take in accordance with our goals. Information is needed to diagnose, model different scenarios and influence its trajectory. This requires obtaining and storing as much relevant data as possible on the scale of agglomerations, neighborhoods or buildings, and then analyzing them to make forecasts for energy, mobility, pollution, water, and so on. We need common and open European databases to achieve a good level of resilience in the face of climate and geopolitical disruptions. Thanks to streams that are processed almost in real time, we can almost manage our cities as systems based on advanced technologies.

Do you see other approaches besides these smart cities ?
Ch.M. Digital technologies, such as artificial intelligence, offer good potential for technologically advanced cities such as Singapore, but there is still a need to show interest in collective intelligence.

WITHIf cities account for 80% of world GDP through services, trade or finance, they produce almost no resources and live outside.

The living world offers us impressive examples of organization on this issue, which we study with biologists. Take termites, where blind workers manage to build huge towers of biological materials that control gas concentration, temperature and humidity, particularly for growing mushrooms. Remember that while cities account for 80% of world GDP through services, trade or finance, they produce almost no resources and live outside.

Therefore, we are also working on strategies for the development of urban areas inspired by biotechnology, promoting access to resources and local capacity development. But measures taken in the short term materialize in the medium or long term, which can be considered a weakness in the face of the acceleration and amplitude of climate change.

You are the head of the Solar Energy Federation (CNRS) (FédEsol). What is the problem of the city?
Ch.M. I work hard to integrate different solar technologies in buildings and cities to provide a local response where energy needs are concentrated. In urban areas, the main problem with solar energy is related to the variability caused by the shadow of houses, with areas with variable lighting during the day. The quality of solar resources is also affected by atmospheric clouds and sensor pollution due to pollution, or even higher temperature levels than in rural areas, due to the impact of heat islands. Many problems need to be overcome.

Visualization of heat islands in Paris and its suburbs, obtained by digital simulation during a beautiful summer evening.

Are other routes to climate-neutral cities being considered?
Ch.M. Faced with human population growth, 60% of the buildings needed to meet our needs by 2050 have not yet been built, leaving us with many opportunities for positive change in our cities. This opportunity. however, this will not be very useful for achieving the goals in the next ten years, as the urban planning process needs to be intervened much earlier: construction programs that are underway or will begin by then have already been identified. Now we have to work on urban planning, which is currently based on a very impressive aesthetic concept, where the buildings of the district have a very correct and orderly planning and height. However, as in the living world, diversity plays a key role. This limits the impact of heat islands, providing better ventilation of areas and improving access to solar resources.

It should be noted that, although cities play a huge role in climate change, they are particularly sensitive and prone to it. Their growing need for air-conditioned cooling can quickly lead to a vicious circle where anthropogenic emissions will increase and local climate effects will increase. In addition, the combined effects of solar radiation, temperature and pollution create comfort and health problems for humans and biodiversity, which increase vulnerability to climate change. Problems are dangerous.

To learn more
The site is dedicated 5 Missions of the European Union

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