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 biomassesover 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.

フィリップ・ベルトランらが綴る本作は、単なる科学書を超えた、地球という巨大な生命系の「自叙伝」です。四〇億年もの間、生命が単なる居候ではなく、惑星の環境を能動的に作り変えてきた「共進化」のダイナミズムは圧巻の一言。金星や火星との対比から浮かび上がる地球の奇跡的な均衡は、読者に宇宙的な視座からの畏怖を抱かせます。 特筆すべきは、人間を地球の「管理者」と定義する終盤の熱量です。緻密な科学的知見の底には、この惑星を慈しむ深い情熱が流れており、環境破壊への警鐘が未来への希望へと昇華されています。読後、足元の大地が鼓動する一つの生命体として感じられるはず。知的好奇心を激しく揺さぶり、地球への愛を再燃させる至極の一冊です。