Climate Science on the Eiffel Tower
It is fitting that the international agreement coordinating action on climate change was negotiated in Paris, because the history of climate science is written on the very symbol of Paris. Inscribed on the Eiffel Tower are the names of seventy-two French scientists and engineers who contributed to the 19th century revolution in science and technology that shaped today’s world. Here are twelve who made discoveries critical to understanding the global climate and to efforts combating climate change.
Antoine LAVOISIER and Charles BORDA made some of the first measurements linking changes in barometric pressure to weather phenomenon. This was a milestone in understanding the mechanics of weather and climate. Their work, which would have resulted in accurate weather predictions, was cut short by the French Revolution in which Lavoisier lost his head to the guillotine.
Antoine-Cesar BECQUEREL discovered the photo-electric effect. This is the basis for photo-voltaic panels used as a source of renewable energy to replace the use of fossil fuels.
Jean-Baptiste Joseph FOURIER was the first, in 1824, to describe the main components of the heat balance for the Earth. The heat balance drives weather and climate, and climate models used to investigate climate change are based on heat balance calculations. In this work, Fourier also described the phenomenon that we now know as the greenhouse effect. At the time Fourier did not really understand what causes the greenhouse effect. That came to light through the work of John Tyndall, 25 years later.
Benoit CLAPEYRON developed the science of thermodynamics, the key to using fossil fuels as a source of mechanical energy and also to understanding the mechanics of atmospheric phenomenon involved in climate and weather. It was Clapeyron who, working during the 1830s and 40s, translated Nicholas Carnot’s theory of an ideal heat engine into terms that practicing engineers could apply. Earlier, James Watt had introduced the use of the indicator diagram, a plot of steam pressure versus volume inside the cylinder over one cycle of the piston, as a tool for understanding and refining the operation of steam engines. Clapeyron used the same approach to describe Carnot’s theoretical results.
Louis-Jacques THÉNARD made the first measurements of the concentration of carbon dioxide in the atmosphere in 1812. Thenard obtained a value of about 400 ppm, which is close to what the global average concentration is today, elevated by a century of fossil fuel use. The carbon dioxide concentration at ground level varies quite a bit, and Thenard’s measurement likely was affected by the proximity to sources of carbon dioxide, such as a fire used for heating his laboratory or even his own breath.
Gustave CORIOLIS and Louis-Marie-Henri NAVIER translated the dynamics of fluid flow at a global scale into the mathematics that are the basis for weather and climate models. Navier developed the universal equations of fluid flow known as the Navier-Stokes equation. And, Coriolis identified an additional factor that must be included in models of fluid flow due to accelerations related to the Earth’s rotation, the phenomenon known as the Coriolis force.
Jacques-Joseph EBELMEN described the geological carbonate cycle that regulates the level of carbon dioxide in the atmosphere over the long-term, and he was the first to suggest that the composition of the atmosphere had been altered by the development of life on Earth.
Urbain-Jean-Joseph LE VERRIER developed the science of weather prediction as director of the Paris Observatory during the 1850s. Le Verrier coordinated measurements by a network of stations to map the movement of weather systems across Europe.
Joseph-Louis GAY-LUSSAC, in 1804, and Jean-Augustine BARRAL, in 1850, each made record-breaking balloon ascents in which they studied the vertical structure of the atmosphere. In the first of two ascents by Barral and his colleague Jacques Bixio, a rip opened in the balloon at the height of 5000 meters, and the balloon and its passengers began a rapid descent. By a stroke of luck the gondola with Barral and Bixio still inside crashed into the small trees of an orchard. This was enough to cushion their impact, and both scientists survived.
