Earth, Our Living Planet

Earth is, to our knowledge, the only life-bearing body in the Solar System. This extraordinary characteristic dates back almost 4 billion years. How to explain that Earth is teeming with organisms and that this has lasted for so long? What makes Earth different from its sister planets Mars and Venus?

The habitability of a planet is its capacity to allow the emergence of organisms. What astronomical and geological conditions concurred to make Earth habitable 4 billion years ago, and how has it remained habitable since? What have been the respective roles of non-biological and biological characteristics in maintaining the habitability of Earth?

This unique book answers the above questions by considering the roles of organisms and ecosystems in the Earth System, which is made of the non-living and living components of the planet. Organisms have progressively occupied all the habitats of the planet, diversifying into countless life forms and developing enormous biomasses over the past 3.6 billion years. In this way, organisms and ecosystems "took over" the Earth System, and thus became major agents in its regulation and global evolution. There was co-evolution of the different components of the Earth System, leading to a number of feedback mechanisms that regulated long-term Earth conditions.

For millennia, and especially since the Industrial Revolution nearly 300 years ago, humans have gradually transformed the Earth System. Technological developments combined with the large increase in human population have led, in recent decades, to major changes in the Earth's climate, soils, biodiversity and quality of air and water. After some successes in the 20th century at preventing internationally environmental disasters, human societies are now facing major challenges arising from climate change. Some of these challenges are short-term and others concern the thousand-year evolution of the Earth's climate. Humans should become the stewards of Earth.

The Stage. Planet Earth: Our Home in the Universe

1. Unique Characteristics of Planet Earth

Act 1. Seven Connections that Set the Scene of Life on Earth
2. The Earth Has an Atmosphere: Connection with the Solar System
3. The Temperature Conditions of Earth are Moderate: Connection with the Earth-Moon System and the Earth's Rotation
4. There is Water on Earth, and it is Mostly Liquid: Connection with the Solar System
5. The Earth's Crust Contains the Building Blocks of Life: Connection with the Gravity of Stars and Earth
6. The Earth's Temperature is Suitable for Life: Connection with Plate Tectonics
7. The Earth Retains its Atmosphere: Connection with the Solar System and the Earth's Gravity and Magnetic Field
8. Life Thrives on Earth: Connections with the Special Earthly Physical and Chemical Characteristics

Act 2. Four Major Connections that Make Living Organisms and Systems Key Players on the Earth's Scene
9. Connections of Living Systems with the Environment Typically Include Feedbacks and Attractors
10. Living Systems, the Earth's Climate and Plate Tectonics are Connected
11. Living Systems, Free oxygen and Atmospheric and Oceanic Carbon are Connected
12. Living Systems, Free oxygen and Atmospheric and Continental Carbon are Connected
13. Living Systems and Atmospheric, Continental and Oceanic Carbon are Connected

Act 3. Two Major Connections by which Human Actors Disturb the Action of the Play
14. Climate Change: Connections between Human Activities, Carbon, and Greenhouse Gases
15. Ocean Acidification: Connections between Human Activities, Carbon, and Ocean's pH Final act. Connections regulate the Earth System scene
16. Non-Living and Living Components of the Earth System are Regulated by Interacting Connections