The same curiosity that allowed humanity to understand astronomical phenomena now offers us a striking insight into what is happening right before our eyes, here on our spaceship Earth. By observing the universe, we have learned to measure the fragility and uniqueness of our own world.
The "macro-organism" Earth is showing signs of fever, and humanity is growing concerned. Floods, storms, tsunamis, and earthquakes fuel a rising anxiety. These natural phenomena, amplified by human activities, remind us that our environment reacts to the pressures we place on it.
Studying ecology and the environment means seeking to understand the mechanisms that govern natural balances, as well as the disruptions we introduce. This section explores the issues, phenomena, and dynamics that shape our planet, in order to better grasp the ecological challenges we collectively face.
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The Principle of Least Action: Why Does Nature Always Choose the Most Economical Path? 
Evolutionary Convergence: Chance, Necessity… or Mirage? 
The Five Mass Extinctions: What do these planetary catastrophes reveal? 
Cryosphere: when the ice giants still protect us
The Nitrogen Cycle: From Air to Life 
The Jet Stream: When the Atmospheric River Overflows Its Banks 
The Carbon Cycle: The Harmonious Interaction of Oceans, Forests, and Subsoils 
Fatal Imbalance: The Unsuspected Power of the Infinitely Small 
The Water Paradox: Without it, no life 
Why 220V Alternating Current is in Our Outlets: A Matter of Physics 
The Last Glacial Shock: The Younger Dryas and Its Impact on Prehistoric Societies 
536: The Year Without a Summer and the Beginning of the Late Antique Little Ice Age 
The Minimal Cell: The Inevitable Emergence 
Evolution of Global Energy Consumption: From Steam Engines to Digital Servers 
The Demographic Transition: Growth or Decline? 
Lake Agassiz: A Deluge that Changed the Climate 
Drunken Forests: Understanding the Phenomenon of Permafrost Thaw 
There is Electricity in the Air! 
Why Doesn't CO2 Fall to the Ground? 
El Niño and La Niña: The Two Breaths of the Pacific That Shape Global Climate 
Endangered Species: Dynamics of Extinction 
The Toxic Legacy of Acid Rain 
Global Warming in Figures: What the Scientific Data Says 
What is Sustainable Development? 
The Aral Sea: A Lesson for Humanity 
Three Gorges Dam: Impacts on Ecosystems 
The Hottest Years Since Records Began 
Magnitude of future global warming 
Earth in Crisis: Collapse or Renaissance? 
Ice on the Brink: The Inevitable Decline of Arctic Sea Ice 
Earth's Water Reservoirs: From Oceans to Groundwater 
Sea Levels Are Rising, But How Fast? 
The Other Climate Threat: Earth Shrouded in Shadow and Humidity 
The Age of the Sahara: From Green Prairie to Stone Desert 
World Population from 1800 to 2100 
Oil: The Fall of a Giant in the Era of Renewable Energy 
Kamchatka King Crab: A Giant of the Oceans 
The
collapse of a society 
Slight Progress in the Global Ecological Footprint 
The South Atlantic Anomaly 
The phenomenon of soil sinking is called subsidence 
Why Is Earth So Often Cloudy? 
The Planet's New Clouds
Desertec: A Solar Dream for Europe and Africa